RASTER IMAGE GENERATOR

Abstract: A raster image graphics subsystem (10) for an acoustic console, or other console requiring sensor and/or graphics imagery, employs extensive parallelism and modularity to enhance performance and flexibility. Parallel specialized image cogenerators (14) respond to commands from graphics and acoustic processors to draw representations of image in bit map memories (16) via an image bus (26). A display controller (20) accesses these representations via a video bus (12) which provides for various mappings of bit map memories to the display controller. Multiple images can be displayed on a single monitor (22) using viewporting techniques managed by a viewport controller (24). New functions and increased throughput can be added to the subsystem by adding additional cogenerators.

Description: RASTER IMAGE GENERATOR BACKGROUND OF THE INVENTION The present invention relates to sensor and graphics display systems, and, more particularly, to a subsystem for drawing images for raster graphics output. High performance acoustic sensor and graphics systems are demanded by several applications. These applications include air defense, and other detection systems used in national defense and combat display consoles. Sophisticated computer-aided design is a target utilization in the commercial realm. Available state-of-the-art graphics systems have been designed to support a specific application with existing technology, but are relatively inflexible, requiring redesign for slight changes in requirements. Examples of such graphic systems include the Hughes Aircraft Company HMD8000, HDP4000, and Common Digital Television Generator (CDITEG, developed by GMHEC for the U.S. Navy), and numerous commercial systems including the Motorola 8250 and Raπrtek 9465. The characteristic of these systems is that "they may not combine sufficient flexibility with state-of-the-art performance to take -advantage of rapidly advancing technology and new applications. State-of-the-art display systems have used fundamentally different architectures for sensor and graphic image generation. This means that a sensor display system generally had low performance graphics capabilities and vice versa. __ It also meant there were very few common electronic module card designs between these systems. In the typical current system, sensor image generation is not directly supported sensor image generation due to performance and architectural- limitations, and new types of image generators cannot be added nor can the memory chip technology be upgraded without significant redesign.- Changing to different raster video formats (e.g., 1280 x 1024, 60 Hz non¬ interlaced) also requires circuit modification and software reprogramming to change raster formats. Such a configuration typically also does not support smart. bit map memories (BMM), that is, BMM which can clear and test windows and provide local read-modify-write (RMW) operations. Another limitation of many of the available systems has been speed limitations due to the processing load on a central processor. What is needed is a graphic display architecture usable for a wide variety of high-performance display systems. This raster image graphics subsystem should be flexible enough to support sensor and graphic requirements, and powerful enough to provide very high drawing speeds, e.g., 50 nsec per pixel. This subsystem should also be able to take advantage of future memory chip technology, and to off-load as much of the graphic management tasks as possible from the host processor. In addition, this architecture should provide enhanced display management features. SUMMARY OF THE INVENTION A raster image generator is provided containing multiple image generators, or "cogenerators", a wide data and address image bus connecting the cogenerators to frame buffers, and a generalized video bus mapping the frame buffers to one or more display control modules. This raster image generator provides high performance and flexibility through parallelism and high speed, wide general purpose bus structures. The raster image generator (RIG) is a high performance digital raster graphic and sensor image generator. The RIG is architected to provide the following features: modular image generation to efficiently implement a wide range of military applications requiring various combinations of sensor (radar, sonar, IR, television) and graphic data; very high speed image generation capability to meet expected military sensor and graphics applications; capability to generate raster video for monitor resolutions ranging from 640x480 to 2000x2000 at up to 60Hz frame rates inter-laced or non-interlaced; provisions for programmable organizing and allocating A the bit map memory, planes to suit various applications, including switching in redundant BMM planes to increase reliability; and support for hardware implemented viewport/ indows with near instantaneous, less than 16 ms response to user commands. The RIG system consists of a collection of parallel image generators, bit map memories, and display and viewport control s which are connected by general purpose bus structures. The image generators and display/viewport control functions are controlled from a host processor across a "host processor interface". The image generators drive a multi-master 64-bit wide general purpose "image bus" to the bit map memory planes. Each of up to 64 bit map memory planes may be up to 4K x 4K pixels in x and y. The memory planes are enabled under programmed control onto the "video bus" which may contain MUXes to allow reallocation of the memory planes assignments. The video bus drives a display control function which converts the bit map o.utputs into color or monochrome video and timing information to drive one or more CRT displays. The RIG system provides for parallelism of image generation. Multiple pixel generators residing on a common image bus may interleave access to the bit map memories. The design of each generator is optimized for efficiency with one type of imagery. The arrangement yields several benefits. Multiple parallel generators provides much higher pixel drawing performance. The special design of the bus arbiter allows interleaved access without * an wasted bus cycles for switching. Generators may be added, removed or duplicated without any hardware changes in the rest of the system. Standard interfaces to the controlling processor and the bit map memories simplify the design of the generators and the controlling software. The RIG architecture is general purpose enough to support as yet undefined imagery types, as well as current imagery types. Current generator types supported include: 2D graphics generators for generation of lines, symbols and conies from graphic commands; 2D polygon fills generators for generation of a texture filled arbitrary region from a list of line segments or endpoints; radar scan converters for generating a representation of radar video and targets and ages (fades) out the video over time, in which case the input is a video signal and controls indicating the beam position and when the radar pulse was sent (trigger); acoustic raster generators for generating various shapes of acoustic rasters from packets of intensity codes, in which case the regions generated must be moved horizontally or vertically over time to show trends; video grabbers for accepting video inputs with associated sync signals and continuously loading video in a region of the bit map memory or storing one image and stopping; and 3D surface generators, for generating smooth shaded, filled regions from a list of 3D endpoints for line segments, in which case the shading is performed such that the resulting image sppears realistic, as though a light were shining on a solid object. The present RIG architecture provides for dynamic data formats. The image bus provides multiple types of read/write transfers including commands and several data formats (lxl pixel in x,y; 4x4, 4x2, 16x1). In addition to the different x,y formats, the transfers may either be "same color" or "different color". In a "same color" transfer all the pixels in a word are loaded with the same color. In a "different color" transfer, a color code is specified for each pixel. Providing for dynamic data formats yields a number of benefits. . Image bus utilization is reduced. The multiple data formats provide much higher efficiency of transfer between generators and bit map memory. Line,, circle and symbol generators can average 3.3 pixels. per transfer using 4x4 and only 1.7 pixels per transfer if limited to using a 16x1 organization, while a polygon filler can average almost 16 pixels per transfer using 16x1 and would slow down to 4 pixels using 4x4. - - In addition, the control of data transfer type at a low level in the system (distributed control) allows different cogenerators to be added without any other changes. For example, a line generator could be replaced with one which produces anti-aliased lines without any software or hardware changes. Also, the bus protocol allows the format to be defined for each bus transfer and mixed in any combination without limitation. Furthermore, general purpose command read/write transfers allow the system to accept intelligent BMM cards which can perform local functions such as ALU operations, self test or window clear. When driving smart BMMs, the software can use the command transfers to send any type of controls or read back data or results. The architecture allows each memory plane to be addressed by one or more logical addresses (up to 16) as well as its physical address (0 to 63) . The user may combine arbitrary groups of planes into "transparencies". Each plane is programmed with the transparency addresses it is to respond to as well as the color bit positions (1 to 12) within the transparency. Each transfer on the bus contains plane address information as well as the pixel information. Typically planes are grouped by data type. For example, one transparency might be allocated for background maps which are loaded by a video grabber, a second transparency could contain radar date and a third could contain symbology such as targets or labels or planning data. The three transparencies could be overlaid to form a composite showing all the information or any combinations of the three could be shown. The provision for logical and physical bit map memory plane addressing provides several benefits. It improves system performance and flexibility by providing * the mapping of the color bits to the appropriate BMM plane in hardware. Normally, the processor would have to determine which planes the image was being drawn into and shift the color bits into the position corresponding to the planes physical address. This reduces the software cost by simplifying BMM management significantly. Fault tolerance is also provided by allowing extra planes to be included in the system which may be swapped under software control with any other plane once a failure is detected. In addition, on-line testing is provided by rotating memory planes. The system can include a spare plane which is rotated through each planes logical position. This has the effect of making each plane a spare at one point in time and it may be tested without ^ any impact on the rest of the system. Furthermore, powerful display management features are provided by allowing logical groups of memory planes to - be turned on and off under software control. Groups of memory planes may be overlaid on the screen like transparencies (e.g., weather could be transparently cover land). The RIG architecture provides hardware windowing and viewporting. The viewport controller receives raster scan timing information from the display control module. It compares the CRT beam position with programmed parameters defining the viewport screen positions and sizes. It then generates the appropriate bit map memory addresses to read data from predefined "windows" in bit map memory into the viewports on the screen. The hardware windowing and viewporting allows arbitrary "window" regions within the bit map memory to be displayed in any arbitrary viewport region on the display surface. Also, this feature provides addition display management features by allowing each BMM plane to be individually enabled within each viewport. This may be used to allow one combination of transparent overlays in one viewport, and a totally different combination of overlays in another. In addition, hardware windowing and viewporting provides an order of .magnitude faster performance compared with traditional software techniques for movement and size changes and window closing. These functions become instantaneous since there is no need for regeneration of the BMM data lying under the viewport. The transformation mapping BMM regions to display regions is performed on the output side of the BMM. Furthermore, each viewport may have different color palette by feeding the viewport identification number to the color lookup table. This selects a different region of the lookup table for each viewport allowing it to use a different set of colors. This has the effect of multiplying the number of available colors in the display system. This effect cannot be duplicated with software techniques. The RIG provides for sensor and graphic display by permitting installation of different cogenerators. The interf ace to the processor and the BMM are unchanged? the BMM and video Output hardware remain the same. The raster image generator system also provides several- functional improvements over previous systems. These include the ability to send commands to^ and receive status from BMM planes, and the ability to change memory word organization for each write cycle to maximize the number of pixels transferred each memory write. Lines, symbols, conies and most sensor images achieve the highest drawings rates when using a square BMM word organization while polygon fill requires a horizontally aligned format- The raster image generator architecture allows each cogenerator to select which format to use and can interleave accesses from each type without wasting bus transactions. Another new feature is the method of addressing BMM planes for drawing. Each BMM plane has a physical address and may be assigned a logical address. At power up, the processor assigns each plane to a logical transparency address and to a color bit position within that transparency. Thereafter, each drawing command sent to a cogenerator is addressed to a transparency. The BMM planes monitor addresses sent on the image bus and only responds to operations addressed to them. The planes may be grouped in an arbitrary order and may be reassigned to a new transparency to completely reconfigure the display system should that be required. Switching a new good plane in for a failed BMM plane is another use for this feature. The raster image generator architecture is very open ended, with a high performance, standardized, general purpose control and data interface bus structure interconnecting the modular functional elements. These interfaces allow the system to be configured in many different ways for different functional and performance requirements. For example, each cogenerator is optimized for a particular type of image generation or manipulation, (symbols, polygons, block move, con converter, etc). The architecture allows the system implementor to select the type and number of cogenerators needed for his specific requirements. If additional. functions or higher performance is needed later, additional cogenerators are added. High performance standard bus interfaces also allow portions of the system to be upgraded or enhanced without affecting the rest of the design. This is an important advantage since commercial memory and VLSI technology is advancing so rapidly. The raster image generator system allows implementors to use the latest high density (low cost per bit) memory devices without redesigning this rest of the system. Another advantage of this architecture is that it increases the speed of transferring data from image generators to the bit map refresh memory by providing a data formatting unit and interleaved bus access timing to implement high speed image generation capability. It has the capability for flexible grouping and assignment of logical addresses (independent of physical address) of the BMM planes to support reconfiguration, on-line performance monitoring/fault isolation, and automatic replacement of failed bit maps (for high reliability). Additionally, the novel raster image architecture has the capability for accommodating a wide range of raster formats, interlaced or non-interlaced for horizontal line rates ranging from, in the disclosed embodiments, 525 to 2000 lines. Further, it supports multiple rapidly updatable hardware windows, which can be stored in spare areas of the bit map memory and displayed as viewports at desired locations on the display surface. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a raster image generator subsystem in accordance with the present invention. FIG. 2 is a block diagram of a display control for the subsystem of FIG. 1. FIG. 3 is a block diagram of a symbol generator for the subsystem of FIG. 1. FIG. 4 is ' a block diagram of a conic/vector generator for the subsystem of FIG. 1. FIG. 5 is a block. diagram of an acoustic display generator for the subsystem of FIG. 1. • FIG. 6 is a viewport display and its correlations to a bit map memory. FIG. 7 is a block diagram showing signal lines constituting an image bus of the raster image generator subsystem of FIG. 1. FIGS. 8a-8g are examples of formats for various transactions along the image bus of FIG. 7. FIG. 9a is a diagram of an image command word format used on the image bus of FIG. 7. FIG. 9b is a diagram of an address cycle word format used on the image bus of FIG. 7. FIG. 9c is a diagram of a data cycle word format for color data of one pixel read from memory used on the image bus of FIG. 7. FIG. 10a is a diagram of a data cycle word format for partial color data for 16 pixels during write or read used on the image bus of FIG. 7. FIG. 10b is a ■ diagram of a word format for a command cycle used on the image bus of FIG. 7. FIG. 11a is a timing diagram of a ADDRESS or WRITE DATA cycle used on the image bus of FIG. 7. FXG. lib is a timing diagram of a READ DATA cycle used on the image bus of FIG. 7. FIG. lie is a diagram of certain other word formats used on the image bus of FIG. 7. FIG. 12 is a perspective view of an acoustic console in accordance with the present invention. FIG. 13. is a' block diagram of a raster image graphics subsystem of the acoustic console of FIG. 12. FIG. 14 is a block diagram of an acoustic channel of the raster image graphics subsystem of FIG. 13. FIG. 15 is a block diagram of an acoustic display generator of the acoustic channel of FIG. 14. FIG. 16 is block diagram of the raster image graphics subsystem of the acoustic console of FIG. 13 showing the major interfaces. FIG. 17 is a detailed block diagram of a host processor interface of FIG. 16. FIG. 18a is a timing diagram of the asynchronous write cycle for the host processor interface of FIG. 17. FIG. 18b is a timing diagram of the synchronous write cycle for the host processor interface of FIG. 17. FIG. 19 is a timing diagram of the read cycle for the host processor interface of FIG. 17. FIG. 20 is a diagram of an address format for an image bus of FIG. 16. FIG. 21 is a diagram of an address cycle for the image bus of FIG. 16. FIG. 22 is a diagram of a single-pixel-mode data cycle for the image bus of FIG. 16. FIG. 23 is a diagram of a different-pixel-mode data cycle for the image bus of FIG. 16. FIG. 24 is a diagram of a command cycle for the image bus of FIG. 16. FIG. 25 is a block diagram of an arbiter and wait path for the image bus of FIG. 16. FIG. 26 is a timing diagram of switching arbitration for the arbiter and wait path of FIG. 26. FIG. 27 is a timing diagram of a write timing cycle for the image bus of FIG. 16. FIG. 28 is a diagram of an address word format for the image bus of FIG. 16. FIG. 29 is a block diagram of a video bus of FIG. 16. FIG. 30 is a timing diagram of a "back porch" horizontal timing for the video bus of FIG. 16. FIG. 31 is a timing diagram of a "front porch" horizontal timing for the video bus of FIG. 16. FIG. 32 is a timing diagram for vertical state information of the video bus of FIG. 16. FIG. 33 is a timing diagram for the synchronization timing of a bit map memory of the raster image graphics subsystem of FIG. 13. FIG. 34 is a timing diagram for a buffer and controller of a formatter for the acoustic display generator of FIG. 15. FIG. 35 is a timing diagram for direct memory access transfer timing with the formatter of FIG. 15. FIG. 36 is a block diagram of the interface between the acoustic display generator and a memory interface unit of FIG. 16. FIG. 37 is a diagram of the format of a data word on the acoustic display generator to memory interface unit interface of FIG. 36. FIG. 38 is a timing diagram of a transfer cycle between the formatter and the memory interface unit of FIG. 15. FIG. 39 is a block diagram of an interface between an image generator and memory interface unit of the raster image graphics subsystem of FIG. 13. FIG. 40 is a timing diagram for a read operation on the interface of FIG. 39. FIG. 41 is a timing diagram for a single color write operation of the interface of FIG. 39. FIG. 42 is a block diagram of an acoustic controller of the acoustic display generator of FIG. 15. FIG. 43 is a block diagram of a controller CGA of the acoustic controller of FIG. 42. FIG. 44 is a diagram of a transfer cycle for the MIU shown in FIG. 16. FIG. 45 is a diagram of a CLRDTA output from the formatter shown in FIG. 16. FIG. 46 is a block diagram of a pixel mover of FIG. 16. FIG. 47 is a block diagram of a pixel mover CGA of the pixel mover of FIG. 46. FIG. 48 is a diagram of formats for command types for the memory interface unit of FIG. 14. FIG. 49 is a diagram of a soft reset command for a bit map memory shown in FIG. 14. FIG. 50 is a diagram of a transparency command for the bit map memory shown in FIG. 14. FIG. 51 is a diagram of a viewport mask command for the bit map memory shown in FIG. 14. FIG. 52 is a diagram of a mode command for the bit map memory shown in FIG. 14. FIG. 53a is a schematic of a viewporting scheme in the bit map memory shown in FIG. 14. FIG. 53b is a front view of the viewporting scheme of FIG. 53a as displayed on a monitor of FIG. 12« FIG. 54a is a sequential view of a waterfalling ' method in accordance with the present invention. FIG. 54b is a front view of the result of the method in FIG.- 54a as displayed on a monitor of FIG. 12. FIG. 55 is a diagram of command formats for a viewport controller of the video bus of FIG. 29. FIG. 56 is a block diagram of a display controller of the raster image graphics subsystem of FIG. 13. FIG. 57 is a diagram of formats for commands for the synchronization CGA of the display controller of FIG. 56. FIG. 58 is a block diagram of a performance monitor and fault localization card of the raster image graphics subsystem of FIG. 13. FIG. 59 is a block diagram of a set scan support card associated with the performance monitor and fault localization card of FIG. 58. FIGS. 60a-e are block diagrams of various performance monitoring methods used with the card of FIG. 58. FIG. 61 is a block- diagram of a set scan data control used with the set scan support card of FIG. 59. FIG. 62 is a block diagram of a hardware driver system for the console of FIG. 12. FIG. 63 is a block diagram of firmware for the acoustic controller of FIG. 42. DESCRIPTION OF THE PREFERRED EMBODIMENTS Two embodiments of the architecture are described. The first is a graphic image generator subsystem which is controlled by an external processor. The second embodiment is an acoustic display system intended for the integrated display of both acoustic sensor and graphic imagery. I* An image processing system Mf with a raster image A generator subsystem 12, shown in FIG. 1, includes provisions for multiple image cogenerators 14, multiple bit map memories ' 1 16, ' a video bus multiplexer 18, and a display controller 2Q which governs the display on an RGB monitor 22. Hardware viewport control is provided by a viewport controller 24. The cogenerators 14 communicate with the BMMs 16 via an image bus 26, while the BMMs communicate with the display controller 20 via a video bus 28, which includes the video bus multiplexer 18. A host processor interface bus 30 provides for communication between the raster image graphics subsystem 12 and a host processor 32. Examples of commands and data sent along the host processor interface bus 30 include drawing commands tό the cogenerators 14, selection signals to the video MUX, viewport priority, size and location commands to the viewport processor, as well as commands to the display controller 20. The image cogenerators 14, a cogenerator bus and memory interface unit 34 are sub-functions within each generator. The display controller 20, detailed in FIG. 2, includes a parallel-to-serial converter 36, a color look-up table 38, and a digital-to-analog converter (DAC) 40 which provides the input to drive a red-green- blue (RGB) monitor. Synchronization among these components and the cogenerators is coordinated by a synchronization module 42 which generates conventional IEEE standard RS * 343 video synchronization signals in response to timing signals from a display clock 44. The host processor interface (HPI) bus 30 provides a path for a graphics or input/output processor to send drawing commands and data and control messages to the raster image cogenerators 14. It is a general purpose bi-directional 16-bit data path. More recent embodiments use a 32 bit wide host processor interface. The host processor interface has been configured to work efficiently with different types of display drivers by providing direct memory access (DMA) handshake lines and WAIT and ACK signals. For example, the host processor interface can drive a display system on a first-in-first-out (FIFO) basis. Alternatively, a fast processor can be used to drive the generator directly using programmed input/output. • The interface has been configured to be easily connected to the standard busses such as the Intel Multibus. This interface supports DMA or programmed read or write rates of up to 200 ns per 16-bit word, with an average drawing command requiring about 3-5 words. Each raster image generator device occupies at least two addresses in the processor 1/0 space. Command conventions and word formats were selected to allow generalized software procedures. The image cogenerators 14, including those illustrated, as well as others, are a family of devices ranging in complexity from a simple gate array device to several 5x5 cards, each constructed to generate one type of figure or image. Several basic types are listed below. By way of example, three cogenerators are respectively illustrated in FIGS. 3, 4 and 5. As will be described in more detail subsequently, a symbol cogenerator 46 of FIG. 3 includes a symbol generator gate array 48 r with a font bank 50, which responds to signals from the symbol generator gate array 48 by outputting to a transform module 54. The font bank 50 provides eight 256 symbol fonts, with unlimited strokes per symbol. The contents of the font bank may be downloaded by the processor or may be stored in ROM. The output of the transform module 53 is a return to the symbol generator. This arrangement makes font selection and modification' convenient. The transform module accepts stroke information as an input and produces scaled and rotated stroke data as output. The symbol generator gate array 48 is controlled by the RD/WR line 54 and a bi-directional 16 bit data path 52 to the controlling processor. The symbol generator gate array 48, in turn, outputs pixel addresses to the memory interface unit 34 via a local address bus 58 using simple WAIT handshake. The address space corresponds to a 4Kx4K BMM address. xe memory interface unit 34 formats the output of the symbol cogenerator 46 for input to one or more of the bit map memories 16 via the direct memory access image bus 26. This transmission requires handshaking as indicated on a REQ/GNT line 60. Performance monitoring and fault localization are provided by the SETSCAN lines 62 and the SIGNATURE lines 64. These functions are described in greater detail below. The symbol generator 46, illustrated in FIG. 3, generates scaled and rotated symbols, alphanumerics and vectors. It also maintains an internal typewrite cursor with automatic carriage return for alphanumeric strings. Eight font sets of 256 symbols or characters each may be downloaded to RAM or stored in PROM. The cogenerator contains hardware windowing logic which may be used to scissor symbols on a pixel by pixel basis to an arbitrary x,y region or to pick a symbol which falls within a region. The symbol generator generates pixels • at a 10 MHz rate which translates into an average symbol drawing time of .005 msec including bus transfers. Additional features of the illustrated symbol generator 46 are a typewriter cursor with programmable line and symbol space, 64 rotate angles with 60 angles being programmable, 16 scale factors with 12 being programmable, window clipping or picking, and 100 nsec/pixel calculation rate. A conic/vector cogenerator 66, illustrated in FIG. 4, includes a conic/vector generator 68, which has access to a sin/cos read only memory 70 in determining addresses for the memory interface unit 34. Commands and data are sent to both the conic/vector cogenerator gate array 68 and the memory interface card 34 on the 16 bit data bus 52 and under control of the read/wr line 54. A local interface bus 58 governs communication between the conic/vector generator gate array 68 and the memory interface unit 34, as well as interfacing to optional anti-aliasing logic 72. The general purpose configuration of the interface bus and the memory interface unit allow the anti-aliasing to be enabled or disabled without any hardware changes. Anti-aliasing requires that each pixel have a different color value which requires the memory interface unit to perform a different kind of memory cycle. This switching is performed automatically by the hardware if anti-aliasing is selected. As in the other generators, the memory interface unit 34 directs its output to one or more BMM via the DMA image bus 26, the communication being regulated by control signals over the REQ/GNT line 60. The conic/vector cogenerator 66 generates tangent and dx, dy vectors and vector chains, rectangles, circles, ellipses and partial arcs. Textures of dot, dash and user specified patterns are available. Contains a hardware windowing circuit which may b used to scissor figures on a pixel by pixel basis to an arbitrary x,y region or to pick a figure which passes through a region. It generates vectors at 100 nsec/pixel and conies at speeds ranging from .5 msec to 4 msec per octant depending on size. One of the other image generators, which can be used, for example, in marine applications, is an acoustic generator 74, as illustrated in FIG. 5. Sensory data is DMA input to a first-in-first-out (FIFO) memory 76 and then directed to a pixel formatter 78. The pixel formatter 78 responds to control signals to provide for different pixel formats. A conic/vector cogenerator 66 is included to accommodate circular formats. A pixel mover 80 with associated RAM 82 provides for high-speed movement of arbitrary rectangles within the displayed image. In the acoustic generator 74, a microprogrammed controller 84 reads 32-bit acoustic data words from bulk memory, and controls the pixel formatter 78, the pixel mover, and the conic/vector generator 68 gate arrays to. produce different raster formats and waterfailing. The pixel formatter 78 is used for raster .update; the pixel mover 80 is used for waterfailing; and the conic/vector cogenerator 66 is used ' for point position indicator formats. Several other types of image cogenerators 14 have been defined. These include a radar scan converter, ' seed area fill generator, NTSC video grabber and image processor. Each cogenerator has identical host processor 16 and image bus 26. The general purpose bus architecture provides both the performance and functionality required for real-time sensor imagery. A radar scan converter cogenerator can be added to convert azimuth/range format digitized radar video inputs into x,y raster format and perform aging on the data in either x,y raster or azimuth order. An image processor cogenerator can be added to perform simple image processing by performing read/modify/write memory cycles and passing the image data through a dedicated arithmetic logic unit (ALU). A seed fill cogenerator can be added to seed fills predefined regions with solid color or patterns. The estimated performance of this cogenerator is a fill rate of around 15 million pixels per second. A polygon fill cogenerator can be added to provide filling of convex polygons of up to 256 sides. Fill rates approach 160 million pixels per second for large polygons. Each cogenerator receives commands and data fro • the controlling processor and generates pixel addresses, color data, and/or pixel enables to produce a raster image. The symbol and conic/vector cogenerators produce pixels at a rate of 10 million pixels per second for lines, symbols and alphanumerics. Since cogenerators run in parallel and may be duplicated, very high writing rates may be achieved. A high degree of modularity is also achieved since di ferent types of cogenerators may be added by plugging in a card. An image bus provides a versatile, low level interface standard at the image cogenerator output, which allows cogenerators to drive image data to the memory interface unit 34 ^ and to read data back from the BMM. It consists of 24 pixel/word address lines, 16 pixel enable bits, 12 color bits, 12 color mask bits, and several control signals. The cogenerator bus allows up to 16 pixels all the same color falling within a single BMM word to be transferred in 100 nsec. Bit map memory write operations require address, color value, and a pixel mask, for word operations, to be provided. Since different cogenerators provide these in different sequences, or in the case of color the value may come directly from a processor rather than a cogenerator, separate load outputs corresponding to each parameter are provided. Each load term is activated when the corresponding data is available. The memory interface unit begins a memory operation when the load address LDADD term goes _ active. It is the responsibility of each cogenerator to ensure that all required parameters have been loaded into the memory interface unit before issuing LDADD. A simple WAIT control provides synchronization. The memory interface unit 34 is a single chip bus controller for the image bus 26, detailed in FIG. 6. The memory interface unit provides a path for the host processor 32 to send commands to and read status from smart BMMs 16. The command path is generalized for growth to complex smart BMM designs containing ALUs, zoom or windowing logic. It allows multiple data sources ( cogenerator/memory interface units) using request/grant arbitration and up to 64 BMM. The primary function ©£ the memory interface unit is to provide an efficient, simple means of interfacing cogenerators to the image bus. In this case, the host processor initializes the memory interface unit, by sending commands through a cogenerator, to perform a particular type of image bus operation such as write pixel, write word or write command, etc. Once initialized, the memory interface unit automatically performs the selected operation each time the load address control input (LDADD) is activated. It will request access to the image bus, issue the appropriate control code, format the address and data words, and transmit them only to the bus in the correct time slots. Several pipeline stages within the memory interface unit assure efficient data transfers. The memory interface unit'34 also contains a special pixel buffer to improve the drawing rates of sequentially addressed figures such as lines, conies and symbols. The pixel buffer may be configured 1x1 (x.y), 16x1 (x,y) or 4x4 (x,y). Each image cogenerator selects the organization which provides the maximum number of pixels per transfer. This would be 4 x 4 for vectors, conies and stroke drawn symbols, and 16 x 1 for polygons and dot matrix type symbols. The lxl format is included to support BMM designs which do not allow full word operations. As address inputs are received from a cogenerator, the pixel enables are collected in the pixel buffer until the address moves outside the word. A pair of pixel buffers are used with one being filled while one is being loaded to minimize overhead. A WAIT is issued to the cogenerators if the memory interface unit cannot accept new pixel data. The image bus consists of a 64-bit multiplexed data/address/command bus, 7 address lines, 5 bits of operation control code, clocks and the request/grant signals from each source. The configuration of the memory interface unit, the arbiter and req/grant handshaking eliminates any wasted bus transfer when switching between cogenerators. A single pixel of 1-12 color bits or a single word of 1-16 pixels (all the same color) may be read or written in one bus cycle (100 nsec). This allows some forms of drawing (area fill) to be performed at up to 160 million pixels per second. A special bus operation is included to allow an 4 x 4 x 4 (x,y,color) or 4 x 2 x 8 pixel block to be read or written in 1 bus cycle. This is designed to support high speed textured area fill or sensor (radar, acoustic) display generation where each pixel may have a different color value. A simple WAIT control is used to synchronize transfers. The area fill cogenerator does not load the pixel buffer one pixel at a time, but 16- bit parallel at a time. It can therefore use every bus cycle on the image bus. All operations on the image bus 26 are addressed either to an individual BMM card, using its physical address, or to a predefined group of up to 12 BMM planes using a transparency identifier. This address value is sent each bus cyel© on the 8 address lines and is compared on the BMM card to its physical address and to its programmed transparency identifier. A wide range of BMM configurations are compatible with the raster image generator architecture. The addressable word organization may be lxl, 4x4, 16 x 1, or 4x2 (x,y), while the physical word organization must be equivalent or a superset (i.e., 32x1 to support 16x1). The BMM address space is 4Kx4K with paging used to expand beyond that. As a minimum, the BMM support one of the image bus write operations, the logical and physical addressing ..logic and the commands to program address and color bit position within a transparency (bit map memory group), and enable or disable the video output. The image bus has a generalized command operation which may be used to control any special functions on the BMM such as windowing, test, fill, and video functions such as pan, zoom, scale, etc. The image bus also allows readback of status from a BMM plane. If a BMM plane cannot execute the image bus cycle, it asynchronously asserts the WAIT signal. Each BMM outputs digital video data under control of either the display address or the BMM serial sync signals on the video bus 28, FIG. 1. The BMM card will interface to the image bus which has the cogenerator clock (at 10 Mhz) and to the video bus which has the video bus clock (at pixel clock rate divided by 4 or 8). These clocks can be different frequencies. The video bus 28 is the path for video display addresses and synchronization to pass from the display 5 control function to the BMM and for digital video data to flow back from the BMM to the display controller 20. In the illustrated embodiment, the video bus MUX 18 and viewport control functions are imbedded into the video bus. Herein, functions are "imbedded" when their 10 existence is transparent to the BMM and display control on each end of the bus. These controllers, as well as alternative imbedded controllers, simply transform the data or addresses ' flowing across the bus under independent control of the host processor. 15. In the case of the viewport controller 24, the* host processor programs the device with the viewport parameters such as display position, size, BMM read address, and transparency BMM groups to be displayed. The viewport controller then compares the display 0 address (which it generates internally) to these parameters. When the display position for a given viewport is reached, the viewport controller outputs the BMM read addresses for the viewport in place of the normal display address it had been passing through. If 5 more than one viewport occupies the same display position, the highest priority viewport is used. Each viewport controller provides a full screen background plus 4 prioritized programmable viewports. The devices may be cascaded to allow up to 20 viewports per display 0 controller. Each display controller has an independent set β£ viewports. Each * BMM plane contains logic which compares a software programmable mask value with the current viewport code sent from the viewport controller. If the mask has an enable bit in the position corresponding to the viewport number the BMM output is enabled. This allows the software to select which planes (transparencies) are being displayed within each viewport. FIG. 6 shows an example of hardware viewport usage in a tactical display system. The hardware viewporting allows an image to be displayed out of one portion of the BMM while an updated!' version of the image is being built in another region. Menus may be stored in the BMM and enabled for display instantly without requiring them to be regenerated each time. The display controller allows a different color palette for up to 8 viewports. The video bus MUX 18, accepts several BMM outputs as input and contains multiplexers to connect any input to any one of the output channels which drive the video bus data lines. The processor programs a connection pattern into the video bus MUX logic which causes the BMM outputs to be switched to the appropriate video bus channel to implement plane toggling or dynamic BMM allocation. Each BMM plane has a 4-bit emitter-coupled logic (ECL) output driver which, when enabled, supplies four horizontal pixels of data per video bus clock to a shift register on the display controller 20. In a system requiring toggling memory planes, these outputs may simply be wire-ORed together and' toggling accomplished by turning the planes on and off by sending commands across the image bus. If dynamic plane allocation is required, a MUXing function may be added between the BMM 16 and the display controller 20 which accepts commands via the host processor interface. The video bus 28 contains 22 bits of display address which the BMM may use directly to read the display data, or the BMM may calculate the display address by decoding a serial control signal which provides horizontal and vertical synchronization codes. The display controller 20 receives 4-bit- parallel digital video data from the BMM 16, converts it to serial, sends it though the color look-up table 38 and video digital-to-analog converters (DACs) 40 to produce RGB color or monochrome video outputs, as shown in FIG. 2. The display control also contains a SYNC gate array which supplies TV raster sync timing, display address for BMM reads, serial sync for BMM use, and the color look-up table download control timing. The image bus 26 governs the flow of commands, data and addresses between the memory interface units 34 and the bit map memories 16. As shown in FIG. 7, the image bus 26 includes an arbiter 88, as well as a system clock 90. The image bus .26 consists of 64 bits of directional data lines, 7 BMM plane select- lines and 5 * control lines. One of the control lines is a wait signal for synchronization and the other four signals indicate the bus cycle. The bus connects up to 8 memory interface units to up to 64 BMMs. Since the image bus is a general purpose bus, other sources besides the memory interface units may reside on the bus to interface with the BMMs. The image bus 26 interfaces to BMMs 16, memory interface units 34, and other sources. The memory interface.units or the other sources have the ability to become the bus master and control the bus. The BMMs, however, do not control the bus. A bus master may perform any of the cycles, described below, available to the memory interface unit. The memory interface unit 34, once in control of the bus, may perform either command or data operations. For each bus operation, the memory interface unit first outputs what type of cycle it is to perform indicted by the bus command (ICMND), and what BMM planes are selected for the operation indicated by the BMM plane selection signals (IPHYS, IGRSEL, IADR) and on the next bus cycle perform the actual command or data transfer. If the BMMs determine that they will not be able to perform the requested operation, they store the ICMND code and issue a WAIT to the memory interface unit. If a WAIT occurs, the memory interface unit stops in its present state until the WAIT is taken away, at the same time is output another IClMND code for the next cycle If the bus is not going to be used for a cycle the memory interface unit sends the code for IDLE to the BMMs. During the time WAIT is active, the ICMND must be set to IDLE. Another time when the IDLE is required is when none of the memory interface units are using the image bus. THe BMMs 16 all perform the same cycles when addressed so that they remain synchronized. If for example, some of the planes are masked out by the color enable field during a write operation, they still perform the cycle without modifying their content. This requirement also synchronizes the generation of IWAIT by the BMMs within a transparency. Either all or none of the planes in a transparency issue IWAIT. The memory interface units write to BMM all the color bits of up to 16 pixels during one bus cycle if all the pixels are the same color, and if the pixels have different colors, the operation involves performing additional data cycles. Each data cycle can write up to 4 bits of color information for all 16 pixels. A mixed mode operation is also possible in which some of the color bits are the same for all the 16 pixels and some are different. The same color information will be sent with the address and the different color information during the following data cycles. Reading the color values of one pixel or partial color bits of up to 16. pixels is possible in two or more cycles. During the first cycle the address is sent to the BMMs 16 and the data is read back during the next cycles. Reading the coior of one p ^ l requires only one data cycle, and reading the color of 16 pixels requires one data cycle for each group of 4 planes. The image bus 26 supports two types of command cycles. One is the "address command" and the other is the "global command" cycle. Only the BMM planes which are addressed will respond to the first cycle, but the second cycle applies to all the planes connected to the image bus. The command cycles are of generic type, and the details of the word formats for the different commands are not defined in this document. The contents of 'the OPCODE and the COMMAND fields are determined based on the type and the capabilities of the BMMs used. Examples of image bus operations include: read color of one pixel, FIG. 8a; read color bits of 16 pixels, 12 color bits per pixel, 4 bits in each group, FIG. 8b; write all color bits of 16 same color pixels, FIG. 8c; write all color bits of 16 different color pixels, 12 color bits per pixel, 4 bits in each group, FIG. 8d; write all color bits of 16 bits pixels with some color bits the same and some different, 12 color bits per pixel, 8 bits .the same and 4 bits different, FIG. 8e; read status of a transparency group, unmaskable, FIG. 8f; send maskable command to all the BMMs to set some parameters, FIG. 8g. The bus arbiter 88 performs operations such as: 1) accept bus requests; 2) priority select bus masters; 3) issue bus grants; and 4) re-clock the BMM WAIT signal. To gain bus access and become the bus master, each memory interface unit must first issue a bus request to the central bus arbiter. A bus request will be issued during a bus cycle. This request is meant for the next bus cycle. The bus arbiter must select the next bus master before the end of the cycle. The selection of possible bus masters can be based on a priority scheme, when the highest priority requestor is always granted the bus, - or some other selection method. Different arbiters can be designed for different system requirements. The illustrated arbiter has the following characteristics. First, Once the arbiter determines the upcoming bus master, it issues a synchronous bus grant to the proper requestor. Second, no cycles are wasted in transferring the control from one memory interface unit to another. Third, operations which require ' more than one bus cycle are not interrupted by the arbiter until they are finished. Fourth, the GRANT . is held active for the last memory interface unit in control of the bus until the memory interface unit has completely finished its operations., i.e., the REQUEST is taken away, and the WAIT is not active either. Finally, the arbiter re-clocks the IWAIT signal for the memory interface units. The image bus signals shown in FIG. 7 have the following definitions. IDATA is a 64-bit address and data bus. All the BMM word formats will be transferred on this bus. It is used as a bi-directional interface between the b ' us elements discussed in the previous section. ICMND is a 4-bit parallel code sent from the memory interface unit to the BMMs. This code is used to define what the upcoming bus cycle will be. The description of these codes are defined in the next section. ICONFIG is a 1-bit code specifying the configuration of the image bus word formats. The data for the 16 pixels, during an image bus half word operation, can be configured either as a 4x4 matrix or a 16x1 matrix. IPHYS is an input signal to the BMMs to specify how the BMM is to interpret the BMM address. The address can be either a physical .or a transparency address. IGRSEL is a 2-bit number selecting the BMMs within a transparency that are to respond to the next data cycle if transparency addressing is used with more than four planes. If physical addressing is selected, these two bits are a part of the physical address for the memory planes. IADR is a 4-bit transparency address. During the next bus cycle, only the BMMs that have this transparency address will respond to the bus cycle. However, if physical addressing is selected, the 2 bits of the IGRSEL are combined with this address to form a 6-bit physical address. -IWAIT is an active low output generated by the BMMs to stop the bus master. This signal should become active as soon as the BMM determines that it cannot perform the next cycle. The bus arbiter upon detecting this signal activates the -ISWAIT which is the synchronous version of the IWAIT signals for the memory interface units. (If IWAIT becomes active after the bus master has released the bus, the arbiter should keep the last master on the bus until the IWAIT is taken away. ) • -ISWAIT is the re-clocked version of the IWAIT signal. -IREQ is an active low output signal from the memory interface unit to the arbiter. This signal becomes active asynchronously when the memory interface unit decides to use the image bus. After completing the bus operation the memory interface unit releases the bus by taking this signal away. -IGRANT is an active low synchronous input signal to the memory interface unit indicating that the request to use the image bus is granted and the memory interface unit may perform its ©perations. The GRANT becomes inactive after the request is taken away. SYSRA is a memory cycle sync signal generated on the clock card and distributed to all the BMMs. SYSCLK is the system clock generated on the clock card and distributed to all the image bus elements. The image bus is capable of performing all the bus cycles that can be specified by the image bus command code ICMND as indicated in the following table. The encoding of the four bits of the ICMND is shown in FIGS. 8a-g. The ICMND word format is shown in FIG. 9a. R/W A/D/C/G AUX Cycle 0 00 0 Write Address Same Different Color 0 00 1 Write Address Different Color Only 0 01 0 Write Data 0 01 1 Write Data 0 10 0 Write Unmaskable Command 0 10 1 Write Maskable Command 0 11 0 Write Unmaskable Global Command 0 11 1 Write Maskable Global Command 1 00 0 Read Address Pixel 1 00 1 Read Address Half Word 1 01 0 Read Data 1 01 1 Read Data 1 10 0 Read Unmaskable Command 1 10 1 Read Maskable Command 1 11 0 Read Unmaskable Global Command 1 11 1 Read Idle R/ —Read/Write 0 = write 1 = read A/D/C/G—Address/Data/addressed Command/Global Command 00 = Address 01 = Data 10 = Command 11 = Global Command AU —Auxiliary bit Read, Address: 0 = 1 pixel 1 = 16 pixels Write, Address: 0 = same and different colors 1 = different colors only Command: 0 = Unmaskable 1 = Maskable Global Commands: 0 = Unmaskable 1 = Idle Each read operation requires at least two bus cycles. During the first cycle the address is sent to the BMM, and the data is .received during the next cycle. Some write operations can be performed in one cycle and some may requires more than one cycle. The BMMs are always able to perform data cycles after each address cycle. The data cycles, however, do not have to follow the address cycle during write operations. The same color information is included during the address cycle and the different color ones are sent during the data cycles. The same color information may or may not be enabled by the AUX bit in the ICMND code. The 12 color enable bits allow selective masking of the color planes. Each bit set to 1 disables different color write operation to the corresponding plane and enable same color writes to the same plane. The different color operations may take up to four bus cycles to complete. Each enabled plane is disabled for different color writes, and each disabled one is enabled for different color writes. These bits can also be used as extended color bits if more color bits are required by a system. Although this cycle is called "Address cycle", for some operations, it contains more information than just the address. It includes chip enables (one bit for each pixel), same color data (12 bits), and color enable bits (one bit for each bit plane). For operations which do not require these parameters, these fields are ignored by the BMMs. Three major word formats are address, data and command; each cycle type has its own formats. The address cycle word format is illustrated in FIG. 9b. The data cycle word format for color data of one pixel read from memory is shown in FIG. 9c, while the data cycle word format for partial color data for 16 pixels during write or read is shown in FIG. 10a. The word format for a command cycle is shown in FIG. 10b. The timing for the image bus ADDRESS cycle and the WRITE DATA cycle is shown in FIG. 11a. The timing for the image bus READ DATA cycle is shown in FIG. lib. X ADDRESS Pixel address if pixel memory is used. Half word address if half word memory is used. Y ADDRESS Pixel address if pixel memory is used. Half word address if half word memory is used. CHIP ENABLES Write enable bits for half word writes. Ignored if pixel memory is used. COLOR Color bits for 1 pixel if memory used. Color bits for 16 same color pixels. COLOR ENABLES Write enable bits for color planes. At each position 0 = disable corresponding color bit. 1 = enable corresponding color bit. All commands should be sent during this command cycle. An IWAIT may be issued during a maskable command cycle. The reason for the command cycle distinction between maskable and unmaskable is to allow the BMM to issue waits when commands will interfere with the BMMs performance. An example might be changing the size of a window when the BMM is in the middle of a window operation. If a command is part of the unmaskable group, then it is sent during the unmaskable command cycle. The IWAIT is not issued to art unmaskable command. The IPHYS, IGRSEL ' and IADR word formats, the timings for which are shown in FIG. lie, are as follows. IPHYS Physical/Transparency 0 = Physical 1 = Transparency IADR Memory select address Transparency address or 4 LSBs of physical address. IGRSEL Group Select For Transparency addressing: 00 = planes 0-3 01 = planes 4-7 10 = planes 8-11 Acoustic Display System In accordance with a preferred embodiment of the present invention, an acoustic console 201, illustrated in FIG. 12 includes two high resolution ' monitors 203, which are preferably color RGB monitors, although, one or both can be monochrome. The acoustic console 201 includes a control panel 205 with a keyboard 207 and trackball 209. Beneath the control panel 205 and monitors 203 is a television acoustic generator drawer 213 for current electronics and an ' expansion drawer 215 to permit extension to new applications and incorporation of advancing technologies. The television acoustic generator 217 of the acoustic console 201 are illustrated in FIG. 13. An input/output port (I0P) 219, manages communications with an external computer. Since high speed is a priority for the IOP 219, the present embodiment utilizes a fast bit-slice processor. The IOP 219 interfaces with a panel processor 221 which provides for interfacing with standard commercial busses along an RS-422 bus. An applications processor 223 and a system PROM and support module 225 interface with the IOP 219 and the panel processor via the host processor interface bus 227 r as well as to bulk memory 229, an acoustic processor 231, and a graphics processor 233, also referred to as local host processors. The bulk memory 229 is connected via a direct memory access (DMA) controller 235 to the applications processor 223, and two cogenerators, an acoustic display generator 237 and a pixel mover 239. The graphics processor 233 controls a conic generator 241 and a symbol generator 243. The image generators of the acoustic and graphics channels draw into bit map memories 245. The contents of the bit map memories are used as raster output by display controllers 257 to drive the acoustic console monitors 203. Some ©f the incorporated features of the illustrated acoustic console 201 include high resolutions television display of 1280 by 1024 pixels with functional emulation of the standard 0J-452 displays. Support is provided for a 256 symbol font, programmable symbols, conies, vectors, rasters, amplitude scans, point position indication (PPI), waterfall updates, and format or line orientation. Increased performance, functional flexibility and growth capability are provided with respect to graphics in area fill, rotation of symbols, increased data load and color. Likewise, enhanced acoustic application is supported by PPI line orientation, elimination of PPI stern blinking, increased data load and color. The incorporating acoustic console 201 is designed to meet the high performance display requirements of the next generation of acoustic sonar systems while also accommodating existing systems. The design is based on current LSI CGA technology which enables the design to be more flexible, modular, compact and reliable as well as less expensive. Because the acoustic console 201 is designed be used for many types of applications, such as surface navy and submarine environments, it is designed with special features so as to be adaptable to these diverse requirements. Some features are included to anticipate the future growth requirements and are not currently used. New systems which utilize all the new features of the unit will gain improved performance, due to the efficiencies they add. Such features as compatibility with high level image definition languages, as well as compatibility with primitive languages, which essentially controlled hardware directly, have been included. The ability to draw images with more than 4 bits per pixel also meets requirements for color images with up to 12 bits per pixel. Larger resolution screens can be accommodated to provide for expansion to a full 4096 x 4096 pixel screen. The functions of the acoustic display generator 237 are all programmable, modular devices which can easily interface to a standard bus. This allows them to be used in a host of diverse applications and system architectures. The performance meets or exceed most currently used acoustic consoles in build and update times. One of the major features of the design is its compact modular architecture, which is based on functional modules, called cogenerators which are highly specialized and high performance units dedicated to a category of drawing type. If unforeseen new functions are needed in the future these can also be added to the bus. Depending on the types of drawing required in the system there are special purpose functions which enable fast image generation. Such functions allow efficient and fast drawing of characters of various size and orientation, conic sections for drawing vectors, curves, circles and ellipses, acoustic raster data unpacking, stretching, compression, and pixel field expansion. - Other functions allow manipulating the existing image in bit map memory at a high rate in such ways as area translation, area rotation, combining or .inverting images and area fills. Some of the main features of the advanced acoustic display generator are the following. All of the cards fit within a single drawer 213 of the acoustic console 201. The monitors 203 are driven with single pixel resolution; monochrome resolution is 4 bits/pixel and color resolution is 8 bits/pixel. Normal and reduced gain emulation are provided, as are blink and reverse video modes. The build rates .are 200 ns/pixel for unpacked data and 50 ns/pixel for packed data. Waterfailing of rasters is between 25 ns/pixel and 40 ns/pixel. Other performance parameters include: circle PPI generation is less than 10 ms with controller or 200 ns*8*radius with the conic/vector cogenerator, vectors can be drawn at the rate of 200 ns*pixel length. The DMA interface allows data to be accessed at 300 ns per 32-bit word. The symbol draw rate is approximately equal to the number of on pixels in the font times 100 ns. All the build, waterfall and vector draw rates include only the build rates with the hardware and not the interpretation and set of times using the controller and control host processor process times are only roughly estimated. It should be added that digital technology is employed to reduce costs, and enhance reliability. The modular constructions allows for future growth. The currently planned uses of the acoustic cogenerator and RIG devices include such diverse acoustic terminals for the surface Navy and the submarine environments. The capability of some of these functions are not tied only to SONAR applications and are applicable to such diverse uses as radar, trainers, simulators, and tactical displays. The graphics processor 233, the acoustic processor 231 and the panel processor 221 can read command or data from the bulk memory 229, interpret those commands and command the implementation of the commands to be , executed by the acoustic display generator 237, one of the graphics generators 243, 241, 249, etc., a standard bus panel via the panel processor 221, or performance monitoring and fault analysis modules 263 or any special hardware function through their local host processor interface (HPI). The acoustic console 201 uses several separate control processors. One for the "acoustic channel" control, one for the "graphic channel" control, and one for the panel interfaces was envisioned for a typical acoustic console. If such parallelism is not necessary then these channels can be combined and controlled by a common high performance processor. The graphics channel, defined by the graphics processor 233, is a dedicated set of cogenerators, and bit map memories which are used to build and store graphic images independent, of the acoustic processors and cogenerators. Graphic images functions include display of text, symbols, and cursors which can also be blinded. The graphic bit map memories are separate from the acoustic bit. map memories so that a change in any text, symbol or cursor does not cause any of the acoustic data to be destroyed in the bit map memories. The graphics channel is controlled by the graphics processor 233 which interprets all command messages in the bulk memory and generates control messages to the symbol or conic cogenerators. It also supplies the data to the cogenerators after reading data from the bulk memory '229 and reformatting it in accordance with the cogenerator requirements. The firmware which is responsible for controlling the graphic cogenerators is called a virtual raster image generator subsystem driver. This standard interface program is used to format messages and data for the graphics cogenerators, bit map memories, and keep system parameter and status data required to manipulate the hardware. The acoustic console 201 includes the acoustic channel 265, which is shown in isolation in FIG. 14. The acoustic channel 265 includes the acoustic processor 231, and the acoustic display generator 237 coupled to bulk memory 229. The acoustic channel 265 also shares some of the bit map memories 245 and the display controllers 247. The acoustic channel 265 generates, updates and stores acoustic images that are displayed on the monitors 203. The acoustic channel uses its bit map memories 245 for storing acoustic data primarily. The acoustic processor 231 controls the acoustic channel from control and data files in bulk memory 229 which it can read and interpret. The acoustic display generator 237 is detailed in FIG. 15 and includes an acoustic controller 267, which responds to the acoustic processor 231, and controls the pixel formatter 269 and, optionally, a conies generator 241. Output is to the bit map memories 245 through the memory interface unit.255. The acoustic display generator also uses a pixel mover 239 and associated line buffers 271 as described below. The acoustic display generator 237 is a collection of special processors that can efficiently build and update acoustic data into bit map memory. The processors are specialized in manipulating acoustic data bases, and building acoustic formats which differ from graphics formats. There is a special need for high speed.build and update capability since acoustic formats use a very large and dense image formats that require the manipulation of a million pixels in less than 50 ms time. For .unpacking data fields from bulk memory 225 and formatting it properly repacked into pixel data- packets and repeated the selected number of times, the formatter 269 is used- with the acoustic controller 267. These two functions cooperate to generate data and address coordinates for horizontal or vertical rasters. The acoustic display generator 237 is also used to build ASCANS and PPI formats using the conic cogenerator 241 or the acoustic controller with a circle build algorithm. The pixel mover 239 functions mainly to manipulate the image already in the bit map memory 245. The acoustic controller 267 is also used as the high speed algorithm processor and control unit to set up, initialize the cogenerators and to interpret all messages from speed 16k by 16-bit memory which is accessible to the acoustic controller and the acoustic processor. The acoustic processor 231 is a microcomputer which serves as the main interpreter of control messages from the external computer. It also formats the control and data into a standard message format for the acoustic display generator 237. The hardware driver program of the acoustic processor 231 generates command files to the local memory 273 based on interpreted commands from the bulk memory 229, which are then used by the acoustic controller 267 to set up and control the other cogenerators in the acoustic display generator 237. A dedicated memory for the acoustic processor 231 stores downloaded control programs from bulk memory, interpreter and hardware driver programs, and test programs; this dedicated memory also stores statistics on current display parameters and a directqry of "the local memory 273 which it services. Each processor 221, 231, 233 has its own independent host processor interface which enables concurrent operations on the host processor interface busses 227. These HPI busses serve to isolate local data exchanges from the system command and data type traffic of the system bus. The local memory 273 is a high speed 16k by 16 bit scratchpad memory used to send commands and formatted data to the acoustic controller 267. It is used by the acoustic controller as a command buffer to the acoustic display generator 237 as well as a control parameter file. The acoustic controller 267 can read the device in a random access way and read an initialized DMA port sequentially. The DMA port access is a single cycle read whereas the random access requires a first bus grant from the acoustic processor 231 followed by an address cycle then the read or write cycle. The local memory 273 does not have a separate address port so the address must be loaded through a common port with the data. Besides command messages the local memory 273 also contains display parameters and control tables for rasters that utilize raster, line descriptor (RLD) tables which are accessed along with the data in the bulk memory 229 in a DMA mode. The RLD table defines the repetition of the input pixels and their location relative to the start of the line. The index tables define the manipulation of the data block to cause orientation of the lines. The use of the local memory 273 can be made to fit various system requirements and needs such as a fast access table for circle generation parameters. This local memory 273 also includes a fast access table for circle generation parameters. The local memory also includes a fast access DMA read port which is accessible in a single cycle by the acoustic controller 267. The bulk memory 229 is accessible in two ways. One way to access it is through its primary 16-bit data port 275 connected to the system bus 277, which port is accessible to devices on the system bus, such as the acoustic and graphic processors, and the system input/output port 219. The other port to the bulk memory 229 is the DMA port 279 which is controlled by a DMA controller 235 that supplies 32-bit data words to the formatter 269. The acoustic controller 267, however, can also access data from the bulk memory 229 by using the formatter 269 as its interface device. The DMA controller 235 is set up by the acoustic controller 267 or the acoustic processor 231 on the HPI bus 227; once initialized, the acoustic controller handshake signals can request data from the bulk memory 229 into one of the line buffers 271 of the formatter 269. The formatted pixel data from the acoustic display generator 237, or one of the graphics generators, is loaded into bit map memory 245 through the memory interface unit 255. This arrangement simplifies the image bus interface for the cogenerators because it generates all the bus commands, bus cycle timing, and contains address, pixel, and color mask registers. The bit map memories 245 have several modes of operation which enables multiple interfaces to utilize the image bus 253 without degradation of throughput. Each memory interface unit 255 allows multiple pixels to be transferred as well as single pixels. The following medes are currently used by the acoustic display generator 237: 1) single pixel load into a 4 . x 4 (4bit) matrix; 2) 4 4 pixel array of 4 bits/pixel with a single or different color; 3) 4 x 2 pixel array of 8 bits/pixel with a single or different color; and 4) 8 1 pixel array of 8 bits/pixel with- a single or different color. These memory interface units 255 also enable a simpler bit map memory design because of their ability to access and manipulate rows and columns of the image bus matrix data. By being able to collect input pixels until the boundaries of the matrix are exceeded and then transferring the matrix, the traffic on the image bus 253 is reduced allowing other cogenerators to use the image bus in a time-shared mode. The image bus 253 is a 64-bit wide bus that allows 16 x 4 bit/pixel data to be transferred or 4 x 2 8-bit/pixel data to be transferred in 2 bus cycles, with a mask matrix which selects which pixels in the matrix are to be modified in bit map memory, and a color mask which selects which set of bit planes are to be enabled for update, and the 12-bit X and Y coordinates of the pixel data. A command cycle, on the separate command lines, always precedes the transfer of pixel data, mask, and address on the 64-bit image bus. The display controllers 257 read the values of the bit map memories 245 to generate intensity and color information to the monitors 203 which are output on the RS-343 interface to the monitors 203. The display controllers are programmable to permit various types of bit map memories to be used with a range of monitors with different timing, and resolution requirements. The display controllers 257 read the bit map memories by supplying the address and control synchronization to the memories in synchronization with the monitors' raster sweeps and synchronization signals. The display controllers 257 also convert the pixel values from the bit map memories 245 into RGB and intensity by using their color look-up tables. The color look-up table is downloadable from the host processor 231 or 233, through the host processor interfaces of the display controllers 257. A separate display controller is required for each monitor since the input data to each monitor is different. Several types of bit map memory architectures can be constructed using the raster image generator subsystem BMM modules. The illustrated bit map memories 245 are constructed as 2k by 2k 1-bit memories that can be combined into 12-bit per pixel transparencies. These can be configured with special features with the use of a viewport controller or without. The viewport function allows the translation of any two dimensional viewport in bit map memory to be displayed on any location on the visual screen. These windows can also be set according to priority such that any overlapping will cause a certain priority to be observed and the highest priority window will be seen. Updating a display screen with a currently displayed bit map memory can cause distortion of the view screen as new data is added to the old since part of the screen reflects old data and part reflects new data. Ping-ponging, or the synchronous swapping of the updated bit map memory with the old screen during vertical retrace, prevents any mixed old/new data to be ever seen on the screen. The ping-ponging of the new bit map memories however can be implemented in several ways besides the old ping-ponging of the whole plane. Because the bit map memories can be made extra large often the plane can hold two viewed screen's worth of data and these halves then can be swapped on and off the visible screen. I building images to these memories the X and Y addresses must - e offset to ensure that the data is being written into the proper portion of the bit mapped memory. The output of these sections can be treated as simple oversized windows. Once sufficient windows can be managed by the viewport function, the various subcomponents of the formats can be assigned individual windows allowing acoustic and graphics to be in a common bit map memory without causing rebuilding of the image when any one of these portions change. The overlapping windows need only be updated in such cases which doesn r t effect the data in the other windows. The acoustic console has two monitors 203 which are both updated and controlled with a common set of acoustic/graphics cogenerators. The images for the two monitors are contained in separate bit map memories and displayed using separate display controllers 257. Color or monochrome monitors can be used with the common acousticdisplay generator hardware modules. The impact of color on the acoustic display generator is minimized by including in the design a 4- or 8-pixel mode. The impact of these modes is a slower build and update rate due to the reduced pixel bandwidth of the busses and processors, causing a 50% reduction in build and move rates. The corrective action, if the 25 same performance is mandatory, is to duplicate the memory interface unit 255, pixel mover 239 and formatter 269 although usually all these are not necessary if there is already a timing margin. The main interfaces of the acoustic console 201 are the system bus 277, the host processor interface bus 227, the image bus 253 and the video bus 259, as illustrated in FIG. 16. The system bus 277 extends from the acoustic console input/output port 219 to the acoustic processor 231, which controls the acoustic display generator 231, and the graphics processor 233, which controls the graphics generators, shown in FIG. 16 as a generalized graphics generator 281. The generators interface with the bit map memories 245 and the display controllers 257 as described above. Besides the main busses, there are other more localized interfaces which connect and synchronize a set of closely related cards. Some of the buses shown in the interface diagram are multiple since the console architecture can be separated into separate channels for higher performance. In such cases, the acoustic and graphics channel have their own host processor interface, image and video bus. The system bus 277 is the major interface of the acoustic console 201 which is used as a channel to communicate to the control processors of the unit and the system memory, which contains all the unformatted data and control messages that the external host computer has sent to the unit. Various system bus types can be accommodated according to the type of "standard" processors used. The system bus 277 supports a multi- processor environment which is 'found on current console designs. Other applications using the Motorola 68000 microprocessors use alternate interfaces. The host processor interface bus 227 is the second major control interface that interfaces to the control processors, that are defined as the local host processors. This interface is used to initialize, and set up the hardware cogenerators which build the image from control and data stored in bulk memory 229. In the illustrated acoustic console 201, the acoustic and the graphics channels each have their own processors, with their separate interfaces and bit map memories, so that they can operate independently of each other for higher build-and update rates. The host processor interface bus 227 connects a processor, e.g. the acoustic . processor 231, with an associated raster image graphics device, e.g. the acoustic display generator 237, using a buffer 283 and a decoder 285 in conjunction with the multiple signal lines, as shown in FIG. 17. The host processor interface bus 227 interconnects nearly all the raster image graphics subsystem and acoustic generator functions to the local host processor which serves as a control processor as it performs all the initialization and commands to the functions. The host processor interface bus 227 is a 16-bit I/O bus which has the required handshake interfaces as well as programmable interrupt modes for the cogenerators to operate independently of one another.. Devices can also be programmed to operate in a DMA transfer mode under the control of an external DMA controller. Data transfers of 200 ns can be performed in the DMA mode. The host processor interface bus 227 is also used to initialize and performance monitor and fault localization sequences. The initialization of some devices such as the controller's microprogram, the display controller's timing and color look-up table are performed as well as the initialization of the power-on reset (POR) at the beginning of operation. Afterwards, during operation, the host processor interface bus 227 serves as the main command path to either give commands directly to the cogenerators, as is done in the graphics channel, or to the local memory 273 which is used as the command buffer in the acoustic channel. If tests are performed, the host processor can access the various functions on this bus to command them to perform a test sequence. The acoustic channel's host processor interface bus is controlled by either the acoustic processor 231 or the acoustic controller 267. When the acoustic controller 267 needs access to the host processor interface bus 227, it must request access to it from the acoustic processor 231. Once given access it can monitor the host processor interface bus 227 for the time required to complete its control sequence which uses the host processor interface bus. Normally the host processor interface bus 227 is released after each short sequence. The devices of the acoustic channel which access the host processor interface bus are the acoustic processor 231, the local memory 273, the acoustic controller 267, the dedicated memory of the acoustic controller, the formatter 269, the pixel mover 239, the display controller 247, and the memory interface unit. The graphics channel devices which access the local host processor interface bus are the graphics processor, the symbol cogenerator 243 and associated memory interface unit 255, the symbol cogenerator 243 and the associated memory interface unit 255, the conic cogenerator 241 and its associated memory interface unit 255, and the area fill cogenerator 249. The instructions for the host processor interface bus are given as follows. AO is the address bit 0 is used by some raster image graphics subsystem chips as the extension of the normal 16 bits of data. ACK/ is the acknowledgement of the receipt of a READ or WRITE request to the device selected by the requesting device having sent a CS/. BUSACK/ is an acknowledge from the processor that it granted the controller's BUSREQ. This is unused by all other functions. CS/ is a decoded address of the device which indicates that the current bus master such as the controller or the processor requests a read or write to the function. D0-D15 is a 16-bit bi-directional interface which is used to send data and commands to each function on the bus, when they are selected by the address. DMARED/ indicates that the function which has been programmed to do a DMA operation is requesting the next command/data word from the bus master. DMAACK/ indicates that the bus master has released the host processor interface bus so that the DMA transfer can be executed. INTACK/ is an acknowledge from, the bus master to the cogenerator indicating that the INTREQ/ signal has been received and accepted. INTREQ/ is an interrupt request indicating that the cogenerator has completed its commanded operation. This signal is enabled by a special command or command enable bit and is otherwise unused and inactive. An interrupt interface is also required if this is used. POR/ means power-on reset and is a master reset generated by the power monitor and can also be generated by the processor. It forces the devices which have a common POR to initialize their controls and registers into a predetermined state. RD/ is a read select indicating that the bus master is requesting a write to a selected function, which is addressed. WR/ is a write select indicating that the bus master is requesting a write to a selected function, which is addressed. WAIT/ indicates to the bus master that the selected device can not complete the read or write operation to the host processor interface bus as long as the WAIT signal remains low. ADDRESS selects which functions the bus master desires to access. The number of addresses used on any system of course is variable depending on the number of devices used. Five bits of address lines is quite adequate for most configurations. The following are host processor interface (HPI) bus interface addresses used in the illustrated embodiment. The format of the microprogram memory address are 15 bits with an additional parity bit. 0000X "Host" processor interface 00010 controller 00011 controller initialize and enable 00100 formatter to MIU HPI interface 00101 formatter HPI interface 00110 pixel mover HPI interface 00111 DMA controller 0100X conic cogenerator 0101X symbol cogenerator 0110X display controller 247 (1) 0111X display controller 247 (2) 10000 microprogram memory input LSW 10001 microprogram memory input MMW 10010 microprogram memory input MSW 10011 spare 1010X viewport interface 1011X spare 11000 local memory data R/W & Increment HPI aAddr. 11001 local memory HPI Address Setup 11010 local memory DMA Address Setup 11011 Spare 111XX Spare Timings for the host processor interface bus 227 are shown in FIGS. 18a, 18b and 19, which illustrate the " asynchronous write timing for the host processor interface bus, the synchronous write timing for the host processor interface bus, and the host processor interface bus read timing, respectively. The cogenerators interface to the bit map - memories 245 through memory interface units 255 which are used to store all the pixel values, addresses and control modes required to update or read various sets of bit map memories. A memory interface unit can receive single pixel, or pixel rovss or columns, or 16 pixels* simultaneously and collect these values until its local 4- pixel x 4 pixel matrix boundary is exceeded and then it outputs to a preselected set of bit map memories 245 on the image bus 253. Various cogenerators can have their own memory 1 interface unit, or a single memory interface unit can be shared. In the case of multiple memory interface units, a bus arbiter prevents bus contention on the image bus. Multiple memory interface units enable multiple cogenerators to be operating at the same time. The image bus 253 consists of 64 bits of bi¬ directional data lines, 7 BMM plane select lines, and 6 control lines. One of the control lines, one is a Wait signal for synchronization and the other five signals indicate the bus cycle type. The image bus connects multiple memory interface units (up to 8) to up to 64 bit map memories. 5 Since the image bus 253 is a general purpose bus, other sources besides the memory interface units can reside on the bus to interface with the bit map memories. The minimum bus cycle time is 100 nsec. The 64-bit data bus is time shared to include 64 bits of 10 pixel data, 12 bits of X and 12 bits of Y address, 12 bits of color enables, and 16 bits of pixel "chip enables" to the bit map memories. Separate lines of six address bits organized in. IADR (4), IGRSEL .(2), and IPHYS(l) determine which individual plane or group of 15 BMM planes is addressed for read or write commands. The image bus field is formatted as shown in FIG. 20 with the fields defined as follows: IPHYS selects the physical address planes when it is equal to 0 or the transparency addresses when 20 it is equal to 1. IGRSEL is the group select line which is used when the transparency is addressed and IPHYS=1. In that case 00=planes 0-3, 01=planes 4-7, 10=planes 8-11. However, when IPHYS=0 then 2.5 the IGRSEL is simply the MSW of the physical address while the IADR is the LSW. IADR is the address of the transparency when IPHYS=1 or the least significant part of the physical address when IPHYS=0. The physical address defines an address for every bit plane which is unchanged and is determined by which the planes can be addressed when they are programmed during initialization. The transparency address assignments are initialized by using the physical address. The transparency address defines a group of planes which can be loaded as a set with pixel data, each plane containing one of the bits of the pixel. A transparency address can contain up to 12 bit plane* which may be loaded in groups. The acoustic transparency can have- 4 bits per pixel, up to 16 pixels at a time, or up to 8 bits per pixel, 8 bits at a time, in the matrix. The matrix mode allows faster reads and writes to bit map memory. In the acoustic channel normally 4 bits or 8 bits per pixel are loaded into transparency addresses in the 4 by 4 or 4 by 2 matrix modes. Single pixel mode is not normally used in the acoustic channel- The address cycle includes 64 bits, formatted as shown in FIG. 21, with the fields defined as follows. COLOR ENA is used to enable each of the 12 possible bit planes which contains each pixel. A 0=disable of the color bit write while a l=enable the color write. COLOR i s us e d when a s ing l e co l or write is performed, in which case the 12-bit field can define the color code of up to 12 bits per pixel . CHIP ENA is used to enable the pixel writes of the 4 x 4 pixel matrix. If the corresponding pixel enable bit for one of the 16 pixels is zero then that pixel will not be written into the bit map memory during a write cycle. One bit allows each pixel to be written to BMM. Y ADDR of the control, word addressees the Y coordinates of the bit map memory. It is used to address the single pixel if the single pixel mode is used or the half work address if the matrix is used. X ADDR of the control word addresses the X coordinates of the bit map memory. It is used to address the single pixel if the single pixel mode is used or the half word address if the matrix is used. The data cycle includes two forms: the single pixel mode, illustrated in FIG. 22; and the multiple pixel mode, illustrated in FIG. 23. The color bit x/y/z refers to the three possible color planes that each of the four fields writes to. The command cycle includes 4 bits of OP CODE, which is used to initialize he bit map memory mode, followed by 60 bits of command " as illustrated in FIG. 24. The arbiter and wait path 283 for the image bus 253 are shown in FIG. 25. The arbiter section includes an encoder 285, an LE register 287, a feedback loop with a multiplexer 289, and a decoder 291 which outputs an IGRANT signal when appropriate. On the memory interface unit side are a control module 293, a mask module 295, a clear module 297, an X,Y address module 299, and a pixel buffer 301, which output to an MIU register 303. The control module 293 governs the 'activities of the inputs to the MIU register 303. On the bit map memory side of the image bus 253, a busy signal from a memory control module 305 can be NANDed with the logic sum of a translated address and a physical address to generate a -WAIT signal input to a flip-flop 307 in the arbiter section. Otherwise, data is output from the MIU register 303 in the memory interface unit. The timing for the image bus cogenerator switching arbitration is depicted in FIG. 26, and the image bus write timing is shown in FIG. 27. The image bus address word format, as illustrated in FIG. 28, includes 1 bit of color enable, 11 bits of color, 12 bits of pixel enable, and 12 bits each of Y and X address. The image bus cycle types are listed in Table I. TABLE I: IMAGE BUS CYCLE TYPES R/W A/D/C/G AUX CYCLE TYPE 0 00 0 Write Address Same Different color 0 00 1 Write Address Different color Only 0 01 0 Write Data 0 01 1 Write Data 0 10 0 Write Unmaskable command 0 10 1 Write Maskable command 0 11 0 Write Unmaskable global command 0 11 1 Write Maskable global command 1 00 0 Read Address Pixel 1 00 1 Read Address Half Word 1 01 0 Read Data 1 01 1 Read Data 1 10 0 Read Unmaskable command 1 10 1 Read Maskable command 1 11 0 Read Unmaskable global command 1 11 1 Idle These control lines define the type of operation the image bus is performing. The video bus 259, detailed in FIG. 29 is the interface which connects the bit map memories 245 to the display controllers 257. The interface is a high speed emitter-coupled logic (ECL) serial interface, which takes 4 bits of serial data from each BMM that is enabled to drive the bus. The video bus 259 includes the video bus multiplexer 261 with £lip-=flops 309 to latch incoming raster data, which can then be selected by the multiplexer 261 for transmission to the display controller 257. The video bus 259 also includes a viewport controller 311, which includes an address generator 313 which responds to the host processor interface bus 227 and synchronization signals from the synchronizer of the current display controller 247. The address generator 313 transmits the addresses to the viewport controller 311 which then sends the appropriate control signals through a bank of flip-flops 315 to a memory cycle controller 317 and an X,Y storage flip-flop bank 319 of " one of the active bit map memories 245. A multiplexer 321, in response to signals- form the memory cycle controller 317, can select the shifted address so that the appropriate raster data is output from the bit map memory RAM 323, for output through the conventional registers 325 and 329 and multiplexer 327. From there, the raster data proceeds through the video bus multiplexer 261 and through the shift register 331 of the display controller 247. The video bus 259 reads out 4 pixels out of each bit map memory, which are synchronized by the display controller to update addresses, vertical and horizontal sync, and pixel clock. The display controller has up to 12 input bits to its table that contains the color and intensity values. These bit map memories actually supply the addresses to the table which then supplies the actual value of the displayed pixels intensity and color. The display controller then converts the values into an analog intensity and color value, by way of its digital-to-analog converter, which can produce an RGB or monochrome signa v l to the monitors 203. The video bus timing for the horizontal state information is given in FIG. 30 (back porch) and in FIG. 31 (front porch), with the fields given the following definitions. -BLANK shows when the video is active on a horizontal line. This signal may be used to blank out the output of the video DACs (digital to analog converters). When this signal is high, the video should be blanked out. When it is low, .the video is active. VADDRO-VADDRll are twelve bits of address provided by the synchronization CGA 333 to show the present line position of the raster display. These twelve bits can be tri-stated depending on the /DSADEN input. This counter is reset at the beginning of both the vertical sync pulse and the vertical unblank. This counter can be used as the display address if user also observes the -VACT output mentioned below. This counter counts the correct line number whether in interlaced or non¬ interlaced mode. The vertical state information timing is given in FIG. 32. The -VACT field is used to show when vertical unblank has occurred. If the VADDR information has to be observed also. The display address is valid only when this output is low. " When this ©utptit is high, the video to the monitor is blanked ou * The bit map memory synchronization timing is illustrated in FIG. 33, with the fields defined as follows. Note: * means a value is incremented. BMMSYNC is a serial four-bit code used to tell the bit map memories the events which are to occur. This output is normally high. A zero on this output indicates the beginning of transmission of the coded sync signals. The next three bits (note: this output is clocked by the CDC clock used on the display controller card) are the actual code which is used to tell the bit map memories one of the seven events to occur. H1P080-H1P087 is eight bits of output provided by the synchronization gate array indicating the' position of the horizontal display. These eight bits can be tri-stated depending on the /DSADEN input. This counter output is reset at either beginning of HI or beginning of H4 depending on how the synchronization gate array is initialized. This counter output is also reset when the counter value is equal to the value stored inside BO register. In conjunction with the H1ACT output mentioned below, these outputs can be used as the BMM display address. HIACT is used to show the active line time for line 1. This output is activated at the beginning of Line 1 Start SYNC code which is activated when the line 1 counter value is equal to the value stored in B ) . This output is deactivated at the beginning of Line 1 End SYNC code which is activated when the line 1 counter is equal to the value stored in B2. H2P0S0-H2P0S7 is eight bits of output provided by the synchronization gate array to tell the position of the horizontal display. This counter output is reset at either beginning of HI or beginning of H4. ' This counter output is also reset when the counter value is equal to the value stored inside B2 register. In conjunction with the -H2ACT output mentioned later -in this section, . these outputs can be used as the BMM display address.. The intent for providing this " set of outputs is that in certain situations one may want to display certain information only on the middle part of the display screen (e.g. sensor data) and maybe display text of the left and right edges. If the sensor data and the text data happen to be stored in different sets of bit map memories, then this second set of display address can be programmed to start its address count at the beginning of the display where the sensor data is to appear. The bit map memories can thus be dedicated to their specific tasks with specific update requirements. -H2ACT is used to show the active line time for line 2. This output is activated at the beginning of Line 2 Start SYNC code which is activated when the line 2 counter value is equal to the value stored in B2. This output is deactivated at the beginning of Line 1 End SYNC code which is activated when the line 2 counter is equal to the value stored in B3. Some devices also have special dedicated interfaces for the purpose of special high speed dedicated control and data transfer. In the case when the memory interface unit is not part of the cogenerator board, the cogenerator output data and control is sent to the memory interface unit through the memory interface * unit IN port. Then the formatter 269 also receives inputs directly from the bulk memory 229 through the DMA port. The acoustic controller 267 and the formatter 269 can also access the local memory 273 through a high speed DMA type port of.the local memory 273 called the L.Memdata port. The acoustic display generator 237 uses these special interfaces since its functions are more distributed than the graphics cogenerators and requires special dedicated paths to minimize transfer time and interference. The acoustic controller 267 is the real time address generator, algorithm processor and synchronizer of the various acoustic generator modules. The synchronization interfaces are dedicated timing and control circuits which mostly operate independent of the controller processor, which configures their operation mode as a setup to the configuration register inside the acoustic controller. The fields of the specialized acoustic controller bus are defined as follows. RUN/HALT is an active high signal from the controller to the formatter which enables the processing and outputting of pixel data to the memory interface unit. The internal sync register enables this mode when RH bit is set high causing the output to go high unless the comparator does not detect the PC<REF condition. INCR/ is an active low increment enable signal from the controller which enables the DU counter circuit in the formatter to increment the current stretching or compression of pixels by one as long as this signal is active. That is if the down/up (DU) counter is 5, temporarily 6 repetitions of the pixel will occur instead of 5. In peak picking (compression mode) there are 6 instead of 5 input pixels compared for peak value to be output once. The IC bit of the sync register enables the INCR/ along with the controller RALU carry signal and RUN/HALT. NORM/ is an active low normalize enable signal from the controller which is an alternate kind of run enable to the formatter used when no output pixels are processed. Instead it is used to read in a word of data from the line buffer and shift it by a certain number- of pixels given by the controller ahead of time. This allows the full addressability down to the pixel level required by some low language level systems. The formatter can start formatting on any pixel in the raster. STNCUR/ is an active low stern cursor enable signal from the controller used to disable the outputting of input pixels by the formatter and instead outputs the immediate register of the formatter which can be programmed to any pixel value by the controller through the HPI interface. LASTPX/ is an active low "last pixel" signal from the controller which tells the formatter that the following pixel it will output will be the last one of the line and it also causes the formatter to generate a FLUSH signal to the memory interface unit following this transfer. OEESETRQ/ is an active low signal from the formatter to the controller which is used to request an repeat-offset word from the local memory, which will follow in the next cycle. The controller reads raster line descriptor (RLD) words from the local memory which contains a field with the offset constant and one with the repeat constant. The repeat constant is used by the formatter as the pixel repeat which we call the "DU". OUTBNDS/ is an active low signal from the controller to the pixel mover indicating that the pixel addresses are out of bounds and the currently output pixels not output to the memory interface unit. NEXT/ is an active low signal from the formatter to the controller which indicates that the formatter will read the next word from the line buffer in the following cycle, as shown in FIG. 34. The next signal will also cause the automatic updating of the AADR counter inside the controller. The next signal always has priority over the write from DMA Port, which is addressed by the BADR counter. It can interrupt it at any time without any delay. The currently executed write cycle will simple be executed following the read, if they coincide. CWAIT/ is an active low signal from the memory interface unit to the formatter and the controller. It is used to prevent the update cycle which follows the output cycle from executing until the wait/signal is off. The update cycle causes the next data and the next address to be input to the memory interface unit. BACK/ the bulk acknowledge is an active low signal from the DMA controller to the controller indicates that the DMA has valid data for the line buffer as' requested by the BREQ/. See FIG. 4, which illustrates the timing sequence. BREQ/ is an active low bulk request signal from the controller to the DMA controller requesting data from the bulk memory which loads the data into the ' line buffer of the formatter when the BACK/ is received. The signal is activated by the BR bit of the controller's sync register, it is disabled by a non-acknowledged BREQ (BRDY) as well as a EMPTY/ from the DMA * controller, or the Buffer Full signal from the BADSR MSB-1 being 1. NEXT/ can also override the BREQ/ since it has priority access to the line buffer. LR/W is an active low signal from the controller cj the formatter's line buffer which is used to enable the writes from the bulk memory input data into the line buffer. The line buffer input is latched so that if a higher priority NEXT/ signal is received at the same time the write can be delayed by a cycle without holding up or repeating the DMA request. The RW bit of the sync register is used to enable the write enable circuitry which will cause a write during each BACK/ signal unless there is a next in which case it follows in the next cycle. The writes are disabled by EMPTY or buffer full indicated by BADR counter msp-l=l. The write operation will also enable the updating of the BADR counter. EMPTY/ is an active low signal from the DMA controller indicating that there the programmed blocks are all read, and the block length counters are zero. No more BREQ/signals will be honored, and this signal disables the further request by the controller. The signal can also be tested by the conditional sense MUX of the controller. PENA/ is an active low signal from the controller to the pixel mover which enables it to run. The signal is used to synchronize external devices. This is a direct line from the sync register of the controller. CENA/ is an active low signal from the controller to the conies cogenerator which enables it to run. The signal is used to synchronize external devices. This is a direct line from the sync register of the controller. PBUSY/ is an active low signal from the pixel mover to the controller indicating that it is currently executing some operation. CBUSY/ is an active low signal from the conies cogenerator to the controller indicating that it is currently executing some operation. FBUSY/ is an active low signal from the formatter to the controller indicating that it is currently executing some operation. BUSREQ/ is an active low signal from the controller to the acoustic processor host processor interface port requesting control of the host processor interface bus. Once granted control by BUSACK,/ it takes control of the bus until the signal is removed. BUSACK/ is an active low signal from the acoustic processor HPI bus interface, which is in response to the BUSREQ/signal indicating that the HPI bus is now under control of the acoustic controller. BADR is a 12-bit address port from the acoustic controller, of which only 5 bits are used for the acoustic generator host processor interface address selection, when the BUSACK/ signal has given control to the acoustic controller. The DMA interface is a special interface between the bulk memory 229 and the formatter 269. This interface is controlled by the DMA controller 235 and the acoustic controller 267. After the DMA controller 235 is configured to perform a block transfer by way of the HPI interface it outputs data to the formatter 269 on request generated by the acoustic controller 267. The acoustic controller 'acts as the main address and synchronization unit of the formatter 269. The DMA and formatter transfer timing are illustrated in FIG. 35, with the signals having the following functions. BREQ/ is an active low signal from the controller to the DMA controller requesting the next 32-bit word from the bulk memory. When the bulk memory is not busy and if the DMA word counter is not down to zero, indicating block transfer complete, then the DMA controller 235 will execute the read. BACK/ is an active low signal from the DMA controller 235 to the acoustic controller 267 indicating that it has valid data on the data output line. This signal also enables the formatter 269 to do a read cycle to -its line buffer at the address provided by the acoustic controller 267 on the AADR lines. PD 0-31 is the 32-bit data word which is read out of the bulk memory 229 by the DMA controller 235. This word normally contains the pixel data word, or the boundary descriptor word, although it can be used to read any words from the bulk memory 14. The data also goes to the formatter's line buffer, which is read out by the formatter according to the address supplied to it by the acoustic controller. The acoustic controller can also read back the data through the formatter's host processor interface bus. DEMPTY/ indicates when the DMA controller 235 has completed the block transfer that it was programmed to perform. Its word counter has been decremented to zero and all further reads will not be performed. The interface between the bulk memory 229 and the formatter 269 uses a bulk memory with a two port interface. " The memory interface unit 255 is the main interface to the bit map memory 245 from the acoustic display generator 237. The formatter 269 supplies the major- timing and data interface to the memory interface unit 255 and it operates in full synchronism with the acoustic controller 267 which also supplies the X and Y address of the pixels. The interface between the acoustic display generator 237 and the memory interface unit 255 is illustrated in FIG. 36, which shows the formatter 269 and acoustic controller 267, with the signal lines to various elements within the memory interface unit 255. The following signals are generated by the formatter and the controller and sent to the memory interface unit 255 during image builds. LDREQ is an active low signal which will enable the memory interface unit to perform a load of the address, pixel data, and the pixel mask into its data matrix and address registers 335. The following memory interface unit signals are strobed with LDRED/; CLOCDM/, CLDENM/, LDXADR/, LDYADR/. CLDMIU/ is an active low signal used to load the memory interface unit command register 335. Data from the host processor interface bus 227 is passed through the formatter 269 and output on the CDATA output port to the memory interface unit 255. CLDMIU is selected by the 4 msb bits of the host processor interface bus when a 1000 is selected. CLDMSK/ is an active low signal used to load the memory interface unit mask register 295, Which is 12 bits wide. The data from the host processor interface bus 227 is passed through the formatter 269 ' and output through the CDATA port of the memory interface unit 255. The mask data furnishes a bit plane mask which determines which planes in the transparency are written to. CWAIT/ is an active low signal from the memory interface unit 255 which will indicate to the formatter 269 and the acoustic controller 267 that the memory interface unit is currently unable to accept the data input, and the LDREQ/ must wait till it is accepted. ADDRESS lines XADR °and YADR are enabled to automatically increment, decrement, or accumulate when the WAIT signal is not received following a pixel load request (LDREQ/). In case an external device is used to generate the address such as the conic generator, the formatter 269 is programmed to wait for a ready signal from it before performing the LDREQ/ to the memory interface unit 255. The XADR and YADR lines are 12 bits each, their mode of operation is programmable by the acoustic controller and can be run independent of the controller program once it is configured. FLSHM/ the flush matrix active low signal indicates to the memory interface unit 255 that the formatter 269 has completed the last pixel transfer and the pixel data in the matrix must be output to the bit map memory 245. LDCLR1,2 is the Load color 1 (8 lsb) and 2 (4 msb) of the constant color register. LDCLR2 is also called CLDINT, load intensity, since the upper 4 bits of the "color" word will normally indicate intensity. LDCLR1 is selected by the 4 MSB bits of the host processor interface data word when a 1001 code is used. CLDINT is selected when the HPI msb bits are 1011. CLRDATA is a data port, to the memory interface unit supplied by the formatter 269. It represents the 16 bits making up 4, 2, or 1 pixels in signal pixel or four, or two pixel rows or columns. The pixel formats are: 1) single pixel of 4 bits or 8 bits; 2) four-pixel row with 4 bits per pixel; 3) four-pixel column with 4 bits per pixel; 4) two-pixel row with 8 bits per pixel; and 5) two-pixel column with 8 bits per pixel. The format of the data word is shown in FIG. 37. In single pixel mode, only pixel 0 is valid and the LSB bits are always the lower bit values. CDATA is a port used to transfer the pixel mask from the formatter to the memory interface unit. The function of the mask is to enable and disable certain selected pixels in the row or the column to be written into the bit map memory. The edges of lines or sections may contain excess pixels when more than one pixel is written at a time. The mask disables these from being written into the bit map memory. The mask register can be loaded with a full 16 pixel mask for the 4 x 4 matrix, however only 4 are needed for a row or column. In case an eight bit pixel mode is generated the mask bits are simply doubled so that four mask bits are generated for the pixel mask and lsb. This is done to simplify the memory interface unit logic and adds no complexity to the formatter since the mask is pre-computed by the controller and loaded into a mask register in the formatter, which knows when to output the leading and trailing edge masks. The address and data update occurs independently of the controller algorithm and is under hardware control. The formatter to memory interface unit transfer cycle is illustrated in FIG. 38. The transfer performs the following sequence. STATE 1: If the formatter is not ready or not enabled by the controller, then wait in state 1. STATE 2: the formatter is ready with data and is enabled by the controller, and will generate a LDREQ/ to the memory interface unit. If the memory interface unit Y responds with a WAIT/=0, then it stays in state 2 until the WAIT/=1, at which time it goes to state 3. STATE 3: the memory interface unit has accepted the pixel data so the next address and pixel is generated. If this is readily done without any delays, then go to state 2, otherwise go to state 1. A generic interface 337 between a raster image graphics generator 339 to a memory interface unit 255, which in case of the graphic channel normally resides on a single card with the cogenerator and memory interface unit, is illustrated in FIG. 39. The read timing for the interface 337 is depicted in FIG. 40, and the single color write timing is illustrated in FIG. 41. In case of the symbol cogenerator 243 and the conic cogenerator 241, the memory interface unit 255 is run in a single pixel mode which supplies the X and Y coordinates of each pixel to the memory interface unit 255 which collects these pixels in its pixel matrix and outputs them when, the "boundaries of the matrix are exceeded. The cogenerator is also used as the memory interface unit HPI interface controller supplying ' the required strobes and tri-state output enables to allow an external register-buffer to connect to the CDATA input bus of the memory interface unit. The display controller 247 uses the values of the BMM to generate intensity and color information to the monitor in synchronism with its programmable timing generator and converts this information into a stream of signals for the RS-343 interface to the monitors. The performance monitoring and fault localization (PMFL) module utilizes conventional interfaces used in conjunction with special test circuits in the hardware that enable the accessing of test data and test sequence parameters which are generated by the tests. This data is compared to the expected correct test data values to determine if the hardware is operating properly. Special serial interfaces are incorporated into most of the gate arrays which are used in conjunction with the standard HPI interface to set up, initiate, and interrogate under test. The function of activity detectors is to monitor sets of bus control signals which are supposed to respond to certain sequences, such as bus request and bus acknowledge and similar types of control lines. Read or write request and acknowledge. Such functions have timeout specifications during which a response of completion should be received. Other discrete type error detectors include * parity detection on buses or gate array generated error flags. These discrete error detectors incorporate two signals, an ERROR DET signal from the detector, and an ERROR RESET signal from the monitoring device. These are input to a special monitor port of the PMFL card set. The functions of the dedicated serial test interface are to allow a direct path to initialize the state of the device and/or read back test results independent of the HPI interface. The interfaces are used during first article tests, system integration, performance monitoring and fault location test in various ways. The serial test interface is able to monitor several types of signals such as: signature signals which are generated by sequencers and state machines, set scan outputs of control and data, and shadow serial which is used to sample the test data results and serial output the results like a set scan- parameter, without effecting the state of the chip. The serial input and output data is sent to and received from the PMFL test cards. Certain tests can be set up by the host processor through the normal host processor interface interfaces and use the serial test interface to monitor the results. The PMFL card set includes the circuitry required to send and receive test patterns which are then sent to a processor for comparison to the expected test results. The fields used with the PMFL function are as follows. SI is a signal frdta the PMFL modules which inputs control and or test vectors to the gate array in a serial way, clocked by the gate array clock. The serial input mode is enabled by the following control lines. TCE=0, TSTRB=1, TSTMODE=0. SO is a Serial Output signal sent to the PMFL modules used to output various types of serial test data such as set scan, signature, and shadow serial. -TCE is an active low input signal from the PMFL module 263 used with TSTRBE to select the type of operation being performed. In general, TCE must be equal to zero for either the set scan, or shadow serial modes to be shifted. -TSTRB is an active low input signal from the PMFL module 263 which is used with -TCE to select the type of operation being performed. Devices which contain internal test logic use this signal with TCE=1 to enable that logic. -TSTMODE is a programmer bit which is set when a test command is given to the CGA by the host. The signal is used to enable the set scan and internal test generator, when these are selected. Since one set of TCE and TSTRB signals may be connected to many functions; the TST MODE is used as a programmed select bit which enables one device at a time. -SIGATE is an active low signal generated by the CGA, which indicates when the CGA is outputting a valid signature. This is used to synchronize the external serial receiver. Signature can be generated when TSTMODE is selected or not selected. The signature is always "valid" when the device is operating, however, it may not be the test signature, and therefore, -SIGATE is used to synchronize the central PMFL function to the event of a test signature. The acoustic display generator 237 is a specialized pixel processor which is designed to build acoustic data formats into a bit map memory 245 based raster scan display. It contains special hardware processors for formatting acoustic input data at high rates. The function also can manipulate the acoustic display lists and command structure of diverse acoustic control files with its high speed bit-slice acoustic controller and accesses 32-bit data words from bulk memory with the DMA controller. The local memory 273 is the main interface to the acoustic display generator 237 from the acoustic processor 231. It is a single card, 16K x 16 two-port static memory. The local memory can be expanded to larger sizes by the addition of more modules. It interfaces to the HPI bus and to the acoustic controller internal bus through two ports. These ports are normally read in a DMA mode. The local memory is used to store the control files, display lists, and special control tables, orientation tables and offsets required to build an acoustic image. Special algorithms also use it to store fast access control data parameters which can be accessed in a DMA-type read only mode by the acoustic controller. The local memory is normally used like a FIFO device in a DMA-type mode since it does not have an external address bus for random access and therefore it operates faster in DMA mode. In the illustrated embodiment, the HPI interface operates at 400 ns random access rate and a 200 ns DMA access rate, provided there is no interference from the acoustic processor. The special interface to the local bus of the controller enables a DMA read only mode of 100 ns for the controller. This port always has priority and therefore it does not allow interference from the HPI bus requests. To random read or write to the local memory requires an address- set up cycle, and, since the host bus has a 200 ns per transfer rate, it can only be accessed at a 400 ns rate per word, and then provided the acoustic controller 267 or acoustic processor 231 already has the control of the bus. However, if the DMA mode is setup with the block address, it can access the local memory at a 200 ns rate on the HPI bus, if consecutive addresses are used. When used by the acoustic controller, the direct port to its local bus can be read in DMA mode at 100ns per word. The controller DMA port always has priority over the HPI interface and overrides any HPI bus requests. When the acoustic controller direct path is used the local memory 273 receives a direct signal from the acoustic controller 267 called LREQ/, requesting the next word, which increments the DMA Address. The local memory 273 uses the two LSBs of the 5 bit address line to address its internal DMA counter and the data memory. Illustrated in FIG. 42, the acoustic controller 267 is a two-board function which includes a 10 MHz Am29116 processor (by Advanced Micro Devices) which has been enhanced with a controller CGA function to perform special pixel control algorithms, address generation, and microsequencing. The device controls all the other* functions in the acoustic display generator 237 through the HPI bus 227, for setups, and direct discrete synchronization signals. The acoustic controller CGA 341 has many uses and can be applied to other applications besides the acoustic controller 267. For example, the controller CGA, without the register arithmetic logic unit (RALU) 343 and microprogram memory 355, makes an elegant DMA controller with the addition of a programmable logic array sequencer 345. The acoustic controller 267 with the addition of serial and parallel interfaces can also be used as an 10 controller to the host computer. In the acoustic' display generator 237, the acoustic controller 267 interprets messages from the acoustic processor, which are placed into hardware command messages. It keeps track of hardware status and statistics such as windows, locations, dimensions of formats, and format types. The acoustic controller generates the X and Y address of the formatted pixel data when building the new formats from bulk memory, in synchronism with the formatter 269 and the memory interface unit 255. Update these addresses automatically following MWAIT/. Synchronization and control of the operation of the formatter 269, the controller address generator, the DMA controller 235, and the memory interface unit are performed by the acoustic controller 267 using discrete synchronization signals and handshaking between these devices. For certain types of raster builds, the acoustic controller reads the raster line descriptor (RLD) tables from local memory 273 on request from the formatter 269 and uses the parameter to update its address accumulators with the "offset" values, while the formatter 269 uses the "repeat" values in the RLD word. Additionally, the acoustic controller 267 generates all controls to the DMA controller required to fill the line buffer of the formatter as well as addresses for reading or writing the line buffer, when requested by the formatter 269 or the DMA controller 235. These functions are fully automatic and are performed in the controller hardware for fast automatic operation. No polling or testing is requested by the controller's processor. A test program sequence can be executed by the acoustic controller during inactive times, and any failures are reported to the acoustic processor along with system status. The acoustic controller also generate special build algorithms for special functions which do not have a hardware cogenerator. Such functions as area fill and circle generator can be readily implemented at a slightly reduced rate compared to the conic cogenerator. A 512-pixel radius circle has been estimated at 10 ms build rate using the conic cogenerator algorithm; The memory interface unit XFER cycle, shown in FIG. 44, is enabled by the A0=0 bit, causing the input data to be transferred over to the CDATA port of the formatter. The format of the CLRDTA output of the formatter is shown in FIG. 45. The Const PX values define a 4-bit pixel value, while in the 8-bit pixel mode two fields define one 8 bit pixel values. To rearrange the data in bit map memory 245 without redrawing or regenerating it from the bulk memory 229, the acoustic display generator 237 uses the pixel mover 239, a processor which operates on 16 pixels in parallel. The pixel mover 239, detailed in FIG. 46 is required for waterfalling and reorienting acoustic images in the BMM without regenerating the image from bulk memory.- The pixel mover consists of a pixel processor 385, detailed in FIG. 47, and line buffers 271 which can read and write 16 pixels in parallel from the image bus 253 in one cycle, following setup. The pixel mover includes an HPI bus interface 387 to interface with the HPI bus 227 which is used to program it. Also included is an image bus interface 389 for access to and from the image bus 253, which is the usual source and destination of its data. The pixel mover 239 can perform the following operations: move, copy, rotate, and combine logically the images from the source and destination areas of bit map memory 245 and the immediate register 391, which is programmable from the HPI bus. The pixel mover can also be used to DMA data into or out of bit map memory onto the HPI bus. The pixel mover includes the following components: sequencer 391, X/Y address generator 393, mask logic 395, pixel processor 385, line buffers 271, and line rotators 397, and HPI and image bus interfaces 387 and 389. The pixel mover is a pipelined processor capable of operating at 100 ns per data transfer in DMA mode.. However, the limitations of current bit map memories limits its performance to 200 ns per read or write. The pixel processor 385 can also perform logical operations on 16 individual pixels while in 4 bits/pixel mode or 8 pixels in 8 bits/pixel mode, in parallel before returning it to the bit map memory 245. The pixel mover processor can be used to: pass pixels from one area of bit map memory to another or from the HPI immediate port to BMM, set the BMM to a constant, invert or combine areas (OR), extract a line image from a combined image (XOR), and display overlapping areas (AND) of the source location from BMM (A) and the destination in BMM (B) or immediate register 391. The variables which are used can originate from the line buffer 271, bit map memory 245, and/or the immediate register 391 which are programmed from the HPI bus 227. An eight-pixel row mode can also be used in color (8- bit) mode or a 16-pixel row mode in 4 bits/pixel mode. In the acoustic display generator 237, the formatter 269 provides the HPI interface port to the memory interface unit 255. The format of the memory ■ interface unit command types is shown in FIG. 48, with he fields defined as follows. MASK defines the bit planes which are enabled to be updated. Up to 12 bits per pixel are provided, therefore 12 bits of mask are supplied. COLOR defines the constant color value which can be loaded. INT is the 4 bits of pixel intensity when using the constant color mode. IP is the Physical address selection (1) or Transparency (0). IADR is the address ' of the transparency when IP=0 or the least significant part of the Physical address when IP=1. GR is the group select which forms the group of the transparency when IP=0 or the MSW of the physical address when IP=1. PRCH is the PIX, ROW, COL, HW build mode selection. MD is the 16x1x4, 4x4x 4, 4x2x8 matrix configuration select. CF is the clear on flush selection. WP enables the 4x4 matrix to map into a 16x1 row. NW enables not writing when the enable matrix is empty. PX is the pixel/HW memory mode. RW is the read or write mode select. P means use the signal RW instead of the external discrete line. CLM selects between: same color, different color, same-different color modes. LK locks the image bus until unlocked by new command. -T00- D/C/S is the data/command/global command select. M is the maskable or non-maskable select. CS is the MUX select for color register between CDATA input port or DLRDTA port input. The acoustic channel which displays only acoustic data formats is stored in a separate acoustic bit map memory set. The bit map memory 245 is based on a 2K wide and IK high memory plane which can be viewported using the viewport controller 311. The bit map memory 245 therefore can be broken into smaller two dimensional windows which then can be displayed anywhere on the screen as a viewport. For example, without segmenting the formats into window, a IK x IK pixel area ping-ponged in the two halves of the bit map memory 245. During updates and waterfalls, the off-line memory is updated and waterfalled then swapped with the on-line screen during vertical retrace time. The previously active viewport then is also is updated and waterfalled and is now awaiting the next update before it is swapped back. Alternatively, waterfalling can be accomplished by splitting the window into two viewports with their boundaries moved after each update to simulate a circular buffer which is displayed concatenated on the screen causing a waterfalling action without any moving of bit map -memory 245 pixels. The only change is in the location in which the pixels are displayed on the screen. This scheme works provides for either vertically or horizontally waterfalled rasters, provided there is single pixel resolution in the waterfalled direction. The bit map memory commands involve: soft reset, see FIG. 49; transparency, Z position, see FIG. 50; viewport mask, see FIG. 51; and mode, see FIG. 52. For transparency, Z position, each bit map memory 245 plane is assigned a logical transparency and a color (Z) position form 1 to 12 within that transparency. Once this is done, the plane will respond to any legal command sent to its physical or logical address. For the viewport mask command, each bit map memory 245 plane accepts a mask containing l's for the viewport in which it is to display data. The mask bits are compared to the current top active viewport (TAVP). The mask bit also enables clearing when the viewport control (VPC) is performing a clear-up operation. Regarding the mode command, each bit map memory 245 plane may be programmed to be in the following modes: 00 = idle, 01 = draw, 10 = display, and 11 = display and draw. The viewport controller 311, FIG. 29, interfaces between the display controller 247 and the bit map memories 245, and controls the bit map memory 245 addresses. It enables the designating of selected areas of bit map memory 245 as windows and can translate the addresses of these window areas to the viewport areas on the screen. Such a mapping is shown in FIGS. 53a-b, FIG. 53a showing the viewports as assigned in the bit map memory 245, while FIG. 53b shows the fields as displayed on the monitor. Viewporting allows the movement on the screen of images without actually moving pixel data in the bit map memory 245. In the case of the acoustic display generator 237, this is used for waterfalling. Waterfalling is simulated using two viewports in FIGS. 54a-b. FIG. 54a shows a sequence from an initial bit map memory 245 setup, to the setup after one update, and, finally, after two updates. FIG. 54b shows the display after the second update. Note that the new return appears at the top of the raster while the old data drops off the bottom of the display. The commands' used to program the viewport and windows areas of the bit map memory 245 by way of the viewport controller's HPI interface 407 are depicted in FIG. 55. The display controller 247, detailed in FIG. 56, includes a parallel to serial converter 409, a color look-up table and DAC hybrid 411, and sync CGA 413 and a clock generator 415. The display controller 247 features programmable blink rates, display address and color look-up tables. All sync timing parameters are fully programmable. The acoustic controller 267 is able to synchronize to external master sync generators. Video rates up to 110 MHz are supported, as are 256 colors from a 16.7 million color palette. The acoustic and graphic .channels and cursors, if these are separated, are combined into a common image according to the table-driven display controller 247 which converts the input bits by way of a color palate to both intensity and color. By generating all the synchronization timing to the bit map memory 245 and the monitor it is able to read bit map memory 245, convert, and output RGB signals to the monitor 203. For each monitor 203, a separate display controller 247 is provided. The output of the bit map memories 245 is over the video bus 259 which is an ECL interface to the display controller 247. The display controller palette and timing can be programmed by way of an HPI interface port by the acoustic processor 231 or the graphics processor 233. The sync CGA commands are formatted as shown in FIG. 57, with the fields defined as follows. B load during blank E ERR,, .EEGG,, ,EEBB enable red, enable green, enable red Bl , B0 cursor size o, s, C of the load cursor attribute command is cursor 0 = on, S = shape, C = color enable D modified interlace S S serration pulses Q equalization pulses SR, G, B sync on R, G, B E external sync R restart after color burst I interlaced H horizontal Active P horizontal position start at H1/H4 C P/8 or P/16 select The performance monitoring and fault localization (PMFL) card group, FIG. 58, consists of four cards they are control bus interface 417, control B 419, Control A 421, and signature generator 423. The PMFL functions include: continuously monitoring specified time-out signals and status signals; monitoring memory error detection and correction (EDC) signals and latching addresses - where faults occur; monitoring global bus address and data parity; generating signatures on command for scheduled performance monitoring (scheduled PM); and testing PMFL logic on cards (scheduled PM). The control bus interface 417 allows the host processor to control the PMFL card group 263 and monitors the host processor address and data bus parity. The major functions of the control bus interface card are: address decode, which allows the host processor to read and write to various registers within the PMFL card group; address and data parity generator, for checking host processor bus parity; and send address generator, which generates a 20 clock shift enable used to read a PMFL register containing the bulk or interim memory address. The control B card 419 contains the logic that continuously monitors and records the status of specific PMFL signals from other cards.. The major functions of the control B card are: ' EDC register, stores error detection code status for bulk and interim memory; timeout status parity register, which stores failure status event, this register is cleared when read by the host processor; card tests, used to test PMFL logic; error flag logic, generates an error flag to the interrupt logic when a failure has been detected; and control B status register, which is a register read by host processor to determine proper operation of the control B card. The control A card 421 contains logic that tests t card PMFL logic, selects the signature ' to be taken, receiv some of the signature data/intervals and sub-interval tests local bus parity, and collects the address where EDC error occurred. The major functions of the control card are: test word register, which stores the -select PMFL card test, and is loaded by the host processo signature word register, which stores the select codes f the interval, sub-interval, and data MUXes; card PMFL te generator, which is used to test the timeout/stat register, memory address/status word register, clock ca timeouts and PMFL status registers; interval MUX, receiv thirteen interval signals from various cards and generat three sub-interval signals to the signature generator, car data MUX, receives eight data signals from various cards a generates one signal to the signature generator car card status register, stores 16-bit status results fr various PMFL card tests; and memory address register, stor the 20-bit interim or bulk memory address, this register serially loaded by the send address generator on the contr bus interface card 417. The signature generator card 423 contains the logi which converts a serial data stream of any number of bit into a 16-bit signature. It also generates the erro interrupt signal. The major functions of the signatur generator card are: interval MUX, which receives seve interval signals from various cards and generates on interval signal to the interval decode; sub-interval MUX, which receives eight sub-interval signals from.various card and generates one interval signal to the interval decode; data MUX, which receives 29 data signals from various card and generates one signal to the modulo-2 adder; clock MUX, which selects the clock signal used to generate .th signature; interval decode, which determines when to star and stop a signature and controls the shift register, signature ready interrupt generator, and modulo-2 adder; modulo-2 adder, which is used to combine (exclusive OR) th selected serial data with four feedback bits from the shif register; shift register, which converts the serial dat stream into a 16-bit word that is read by the hos processor; signature ready interrupt generator, whic generates an interrupt to the host processor when signature is ready to be read by the host processor; PMFL interval generator, which generates a test signatur used to verify operation of the signature generator card and error interrupt generator, which generates an interrup pulse to the host processor when an error has been detected A set scan support card 425, FIG. 59, provides dat and control signals for the set scan interface. The se scan support card is of the PMFL card group and i controlled by the host processor via the PMFL local bus The major functions of the set scan support card are ser input data memory, I/O shift register, serial output memo command register decoder, shift/strobe counter, comm sequence generator, and shift control. The serial input data memory 427 is be loaded by host with data that is to be transmitted to the CGA via I/O shift register 429. The I/O shift register is used transmit and receive serial data. Data to be transmitted loaded from the serial input memory and shifted to the via the SERIN line 431 and received data on the SEROUT li 433 is converted to parallel and loaded into the seri output memory 435. The serial output memory 435 is loa with data received from the transmitting CGA on the SERO line 433 via the I/O shift register 429 and read by the ho processor. The command register 437 stores the operati commands received by the host processor. Card operatio are controlled by the following command register bits: SEROUT Enable enables CGA output data to be loaded into t serial output memory 435 and causes -TCE be generated. No data is loaded if the shi counter 439 is not loaded. SERIN Enable enables CGA input data ' to be read from t serial input memory 427 and transmitted to CGA. This also causes the -TCE to generated. No data is transmitted if t 5 shift counter 439 is n loaded. TSTB Enable enables the -TSTB to the CGA for the numb of clocks set in the strobe counter 441. Read Shadow Enable causes -TCE and -TSTB to be generat for the number of clocks set in the shi counter 439. Data received on the SERO line 433 is loaded into the serial outp memory 435. When this bit is set, the SERO Enable is a "don't care" and the SERIN Enab should be reset. Device Address MSB tells the host processor to load a tw bit address to read/write serial inp or serial output memory, and o write the shift counter 439. ©r stro register. Device Address LSB is the LSB of the two-bit code used " address various set scan support ca devices. A command decoder 443 decodes the host process address bus to load the command register 437, start a tes or perform a set scan support card data transfer. The shift and strobe counters 439, 441 are loaded by t host processor and determine the length of -TCE and -TS respectively. The command sequence generator 445 contro the generation of -TCE and -TSTB. It also controls seri input memory read and serial output memory write operatio during a test. The shift control logic 447 provides the I shift register 429 with -shift, load or do nothing (SO SI) commands. CGA test circuitry is used in design checki production test, performance monitoring and fa localization. First article tests consists of te performed by the CGA producer and the designer to determ if various CGA functions are operating properly. The m function of the circuitry is to locate CGA faul Production tests are performed by the CGA producer determine the working level of the device. The m function of production test circuitry is to detect majority of failures quickly. Performance monitoring . is done while the CGA mounted on line. The main function of performan monitoring circuitry is to detect on card stuck at nodes test CGA functions. Fault localization is done while the CGA is moun on a circuit card and the system is off line. The m function of fault localization circuitry is to locate card where the stuck at node exists. A number of te methods, illustrated in FIGS. 60a-e are available to me the various test function requirements. The set scan method, illustrated in FIG. 60a, tak operational flip-flops used in counters and registers and allows them to be reconfigured as shift registers. Th allows serial data transfers between a control device 4 and the CGA under test. The CGA cannot be us operationally during the time data transfer is taking plac Also all the CGA flip-flops are connected in serial an therefore data transfer effects all the devices in the path The control device must provide data in, shift enable strobe, and read the data from the CGA. In the signature compression method, critical signal are exclusive ORed together and generate a single output, a indicated in FIG. 60b. The output is shifted into signature generator over a period of time (16 clock minimum). The CGA also generates an interval and su interval signature generator. - In the data read back method, a data path is provide (through a MUX 457) from a registered device 455 so that it value can be read (generally by the host processor). Th reading device must assure ' the value is stable when it i being read. This method is shown in FIG. 60c. In the shadow serial method, as indicated i FIG. 60d, a shift register 449 is parallel loaded at som point in time, the data is shifted out to the signatur generator under the control of the PMFL function. This i not part of the set scan chain and a separate shift contro must be provided to read the data out. The shadow parallel method is similar to data rea back except that a non-operational register 459 and MUX 461 are required. This method is illustrated i FIG. 60e. The test pattern generator provides built in tes logic that reduces the time required to toggle CGA data The implementation depends on location (input, intern output) within the CGA. The test sequence generat provides built in test logic that reduces the time requi to toggle CGA sequence bits. Four modes of operation for the set scan interf are controlled by the -TSTB and -TCE input signals. The are nondestructive readout, run test, shift data, and outp signature. The selection logic for these modes illustrated in FIG. 61. Shadow serial data readout may accomplished by adding a separate shift enable or removi shadow serial readout. The shadow serial readout mo causes data in a shadow serial register 449 to be shift out on the SEROUT line .433. Data loaded into the- test enable register 451 ANDed with the test strobe (-TSTB) " to produce signals th test various CGA functions. Data is loaded into and re out of the CGA at the same time during the shift data mod A scan register 453 is configured as a shift register. The serial output data (SEROUT) signal is the output of t CGA's signature generator. The set scan interface signals are as follows. -TCE is an active low input which enables the seri shift function of the set scan register. Th allows the set scan register to be loaded and re out. -TSTB is an active low signal used to generate signa that test various CGA functions. It is also us with the -TCE "for nondestructive readout of th set scan register. -TSTMODE is a programmed control bit which is set when test command is given to the CGA by the host. Th signal is used to enable the set scan and interna test generator. SERIN is a serial input to the set scan path, This i the starting point of the set scan chain. SEROUT is the output of the set scan register, signatur generator or shadow serial register (if used) This is the last bit of the set scan chain. The acoustic firmware is presented in the context o the hardware driver system 501 shown in FIG. 62. Thi driver includes an interpreter 503, which feeds an inpu buffer 505.. The input buffer 505 feeds both a hardwar driver 507, and a control file formatter 509. The hardwar driver interfaces with the PMFL test files 511, a loca memory manager 513, a system status module 515, a messag buffer FIFO 517, an I/O control 519, an initialization fil 521,- and the control file formatter 509. The control fil formatter 509 governs a vertical raster format section 523 a horizontal raster format section 525, a PPI format sectio 527 and an ASCAN format section 529. The message buffer FIFO 517 sends messages to the I/ control 519, which in turn communicates with a hardwar status port 531. Both the message buffer FIFO 517 and th I/O control 519 interface with hardware such as displa controllers 257, local memory 273 and microprogram mem 355 via the host processor interface bus 227. Note th for the purposes of the host processor interface (HPI), acoustic processor 231 is the host processor for acoustic channel. It is to be distinguished from the h system and host computer which are external to the acous console. The acoustic processor 231 interprets commands data sent to the console 201 from the system host. Based the interpreted commands, the acoustic processor 2 instructs the acoustic controller 267 to perform t appropriate action. The acoustic controller 267 will t initiate and monitor the hardware (formatter, pixel mov MIU, etc. ) required to perform the operation. While acoustic controller 267 performs the desired task, t acoustic processor 231 is freed to interpret the ne command or perform required data base management. In the relationship between the acoustic process and the acoustic controller, there are three bas software/firmware packages: the interpreter, the hardwa driver, and the acoustic controller firmware. T interpreter and hardware driver are resident on the acoust processor, and are written in a high level language such Pascal or C so they may be transported between differe microprocessor systems. The acoustic controller firmware is microco developed specifically to permit the acoustic controller build acoustic formats. The interpreter is run on t acoustic processor and is used to interpret comman recεived from the host. The interpreter is highl application dependant. The hardware driver is a program run by the acousti processor 231. Primarily, the hardware driver provides standard interface to the acoustic generator hardware; thus a single hardware driver can be used in very differen applications. The hardware driver includes programs that creat specially formatted control files, it also keeps syste statistics files on viewports, bit planes active and off format types on screen and their location and associate control files. It also manages the local memory files fo the acoustic display generator 237. It knows where al parameters are for- each format type in local memory and ca update it and inform the acoustic controller of which file to reprocess through a display list. Additionally, the hardware driver 507 transfers tes files to the local memory for PMFL testing, and b monitoring the status of the acoustic display generator a knowing the type of operation being performed it can s cause test programs to be done during dead times and monit the status of the results. The hardware driver for t illustrated embodiment is written in a high level languag C, for hardware portability. However, some of the routine however, can be rewritten in the appropriate assemb language to enhance speed. One of the tasks of the hardware driver 507 is load the acoustic generator local memory 273. The loc memory contains several parameters stored in disp parameter blocks that describe each of the formats be displayed. For example, information about the type format, the location on the display, build directi waterfall direction, etc., are stored for each displa format. All of this information is initially loaded by hardware driver 507 based on parameters passed by interpreter. The hardware driver 507 is also used to pass comma to the acoustic controller 267 in order to initiate vari command sequences. The following are some of implemented commands: display format, remove format, cl screen, clear area, set clipping window, set viewpo define waterfall area, waterfall area, pixel move ar reorient format, update line -waterfall, update line waterfall. These commands, with the appropriate paramete are passed to the acoustic controller 267 for execution. The functioning of the acoustic controller firmw is illustrated in FIG. 63. The acoustic processor interfaces directly with a message handler 533 for cert operations 535 such as status read, initialization, halt test routines. Otherwise, interfacing is through lo memory 273. A command file 537 communicates b directionally with the local memory 273. The command f also directs the activities of the routines 539 f configuring the acoustic display generator 237, which turn governs the build process algorithms 541, e.g. bui update, waterfall, orient, erase, readback and test. The acoustic display generator 237 responds t commands form the routines 539 which configure it and th results of the build algorithms 541 to draw the determine figures into bit map memory. The configuring routines hav DMA access to bulk memory 229 for address, bulk load, ru and halt routines. The bulk memory 229 also supplies data boundary descriptor word (BDW) and orientation inputs to th acoustic display generator 237. The acoustic controller firmware is used to drive th acoustic controller CGA 267 and associated Am2911 microprocessor. The tasks accomplished by the acousti controller firmware are outlined below. During system initialization, there are severa devices which must be initialized; the acoustic controlle 267, formatter 269, pixel mover 239, memory interface uni 255, bit map memories 245, sync 361, and other device (depending on system configuration), refer also to FIGS. 4 and 43. During power-on reset (POR), a default syste configuration is obtained from the acoustic controller micr memory 355 which allows it to be loaded with microcode fro the HPI bus 227. Once loaded, a configure command to th acoustic controller 267 puts the devi.ce into operationa mode. The display controller 247 must also be initialize with a color look-up table and timing information fo running the monitor 203. Bit map memories must be cleared Otherwise, most devices revert to a known off-state afte receiving a power-on reset. During format builds, th acoustic controller 267 accesses local memory 273 to obtai the parameters required ' to reconfigure the formatter 26 pixel mover 239, and memory interface unit 255 based on t particular build algorithm. The build algorithm generator 541 provides algorith for building ASCANs (vector, dot, and connected dot), PPI and rasters (horizontal and vertical, waterfalled a non-waterfailed). Orientation is provided to PPI, raster ASCANS. Additional routines permit vertical/horizont moving of a predefined area, and waterfalling of a area by given number of pixels. Circle generation for PPIs can al be accomplished in the acoustic controller firmware, witho a conies cogenerator. New format features can be added the acoustic controller to meet future requirements. The local memory 273 contains information required the acoustic controller 267 for building acoustic format The data is stored in display parameter blocks downloaded the hardware driver during format setup. The type information stored in the display parameter is indicat below. Display Format indicates the type of acoustic format to displayed, e.g. ASCAN, PPI, horizontal vertical rasters. It also determines h some of the fields are interpreted. F example, line-to-line- spacing for a PPI is be interpreted as the circle-to-circ spacing. Data indicates the starting address in bulk memo where the line to be built is located. Data Length gives the number of words needed to build t line. BDM Start provides the bulk memory location of t first word of the boundary descriptor wo table. BDW Length gives the number of words in the bounda descriptor word table. "0" indicates th data is packed; "1" indicates that the sa boundary descriptor word is to be used f unpacking all data. X Start is the X coordinate start position of t format. Y Start is the Y coordinate start position of t format. Line-to-Line X is the spacing between pixels in the direction. Line-to-line Y is the spacing between pixels in the direction. Scan Direction is the direction in which to step out pixe within a line. Build Direction is the direction in which to build t additional lines of data. Line Repeat is the number of time to repeat the curr line. This is used for "thickening" line. DU/BIN specifies the number of times to repeat e pixel as it is stepped out. Bins/Line is the total number of input bins required build the output line. Pixels/Line is the total number o f pixel s in t resulting output l ine . Thi s is us primarily for defining waterfall areas . Section Gap defines the gap width in pixels for a G- type sectioned raster. No. of Sect is the number of sections per raster line a sectioned raster line of a section raster. Section Length is the length of one section of a section raster in pixels. Orientation Ena indicates if orientation is to applied. Orient . Sel indicates where to obtain the orientati information. Orient. Mode describes how ori ented data is to displayed, such as display before rollove display after rollover, display all, o brighten at rollover. Bits Per Pixel defines the number of intensity bits in th stored data. Waterfall indicates the type and direction o waterf lling . Rotation gives the section orientation or rotation. No. Scan Lines gives the number of lines in the format. RLD Index supplies the start address of the tabl containing the raster line descripto begin/end pairs. Orient Table provides the start address of the orientatio table. Window Type describes the type of waterfalling to occu in the window, either horizontal or vertical Window XI defines X minimum of window. Window X2 defines X maximum of window. Window Yl defines Y minimum of window. Window Y2 defines Y maximum of window. Start Line defines what line of the window should displayed first in a multiple viewp waterfalling algorithm. Viewport XI defines X minimum of viewport. Viewport X2 defines X maximum of viewport. Viewport Yl defines Y minimum of viewport. Viewport Y2 defines Y maximum of viewport. The display parameter blocks are shown below. DISP. FORMT FMT Defines type of format, e.g., ASCAN, PPI, horizontal or vertical raster. DATA ■ DAT Data block start address 1&2 DATA LEN. DL Data block length in bulk mem. BDW START BDW BDW start block Address BDW LENGTH BDWT 0=packed, l=single wrd, >l=table X START XA X start address, ref. coordinate Y START YA Y start address, ref. coordinate LINE TO LINE LLX X Offset, line-to-line delta X LINE TO LINE LLY Y Offset, line-to-line delta Y SCAN DIR SD Step out direction of pixels BUILD DIR BD Build direction LINE REPEAT LR Display line per raster line DU/BIN DU DU/Bin, stretching of input bins BINS/LINE BL Input Bins per line PIXELS/LINE PX Output picels per display line SECTION GAP GAP Section Gap NO. SECTIONS NS The number of sections per line. SECTION LEN SL Section Length ORIENT ENA OE Orientation performed=l ORIENT SEL OS Orientation source select ORIENT MODE OR Orientation type 000 Display all 001 After rollover 010 Before rollover Oil Intensify BITS B No. bits per kernel (per pixel) WATERFALL WF Direction of waterfall & type ROTATION ROT Section orientation or rotating NO. SCAN LIN NL No. of scan lines R.L.D.INDX RLD Start address of index pairs ORIENT TBL ORT Orientation table start WINDOW SEL WS Selects the window used (1 of 16) WINDOW TYPE WT Window type Vert/Hor, HW/SW WINDOW X1D X1D Display window X min WINDOW X2D X2D Display window X max WINDOW Y1D Y1D Display window Y min WINDOW Y2D Y2D Display window Y max START LINE SLN Used in hardware windows VIEWPORT X X1S Storage X min VIEWPORT X X2S Storage X max VIEWPORT Yl Y1S Storage Y min VIEWPORT Y2 Y2S Storage Y max DISABLE 7s D7S Format of pixel with value of 7=0 The raster line descriptor address (RLD Address) is the sum of the beginning, rotation value and orientation values, i.e., RLD Address = RLD Begin (RLD) + Rotation Value (ROT) + Orientation(ORT) . The display format also has 6 subtype definitions Unpost = clear out the format from the screen & certain parameters. Update = waterfalled update, adds update line after waterfalling. Line = non-waterfalled update of the line with new data. Post = builds a. new format line, updating parameters. Instal = loads the display parameter block, and initializes it. Remove = clears out the display parameter block from the memory. Only the Instal requires the whole display parameter block to be input, all the others require only a few pointer values, things that are changed to be given. The bulk memory acoustic data files have many organizational formats. Many of these formats can actually fit into the following data organization. The data is segmented into blocks and the blocks into elements. The display may start on any block or any element and use as many elements per block or as many blocks as required. The meaning of various parameters in the data block may vary slightly, according to different formats, but they will all have a similar structure. In some applications, the block can refer to a ping of data, while the element refers to one range worth of a particular ping for all beams and bearings. The blocks can be treated as individual pings of the vertical beam and different orientation beams are not mixed. The whole structure of the blocks and the elements are always treated as two sets of circular buffers which may wrap around when the number of elements and blocks is not yet completed. Updates can be entered into an unused element or unused block depending on the data structure used. The computations and parameters are all in the acoustic processor 231 and not in the local memory 273. The processor gives only the blocks start address pointer and the data block length to be used for builds and updates. If successive blocks are needed then the processor will supply them after each is completed (or in a table format to local memory). The bulk memory 229 stores the data block and the associated boundary descriptor tables, and are accessed by the DMA controller and used directly by the formatter 269. The acoustic controller 267 is also able to read out orientation fields which are imbedded in the data blocks. The local memory 273 stores all tables needed 1 by the acoustic controller 267 to generate its pixel offsets, orientation, and repeat values. For certain modes, the local memory can be used to speed up parallel operations of the acoustic controller 267. The local memory 273 has a read-only DMA port which is directly accessible for the acoustic controller input with no interference, and this port has priority over the HPI port. The acoustic display generator 237 has the capability to format image data for the bit map memory 245, into special blocks called windows which can be manipulated by hardware and positioned anywhere on the visible screen called viewports. By using this feature the moved format need not be actually regenerated or pixel-moved and this saves considerable processing time. In the illustrated embodiment, the bit map memory has the capability to define a viewport with a resolution of 1 pixel vertical and 32 pixels horizontal. This allows vertical waterfalling to be used by splitting the window into two viewports and positioning them in the proper position to cause the appearance of waterfalling without actually moving data. An alternative embodiment uses bit map memories with single pixel resolution in both the X and the Y axis. . The window then is treated as a circular buffer by the acoustic controller. In accordance with the foregoing, preferred embodiments and variations of the present invention have been described. Those skilled in the art can readily determine further variations and modification provided for by the present invention. Accordingly, the scope of the present invention is limited only by the following claims.

Claims: CLAIMS What is Claimed Is: 1. A raster image generating subsystem (10) comprising: plural electronic memories (16) , each memory being adapted to storing and transmitting image data in response to received signals; plural image generators (14) , each adapted for outputting signals representing image forms selected from a predetermined class of image forms, each said generator (14) being adapted for outputting such image forms in response to received signals; an image bus (26) for mapping the outputs of said image generators (14) to said memories (16) , said image buέ (26) being adapted for receiving signals so that said mapping is programmable; a display controller (20) adapted for addressing an electronic memory (16) and translating data received therefrom into signals displayable by a read-out device (22) ; and a video bus (28) for mapping at least one of said memories to said display controller. 2. The subsystem (10) of Claim 1 wherein said image bus (26) supports dynamic word formats. 3. The subsystem (10) of Claim 2 wherein each of said plural image generators (16) determines according to its function a word format for transmissions along said image bus (26) . 4. The subsystem (10) of Claim 1 further comprising a hardware viewporting controller (24) to map arbitrarily defined rectangular regions of said electronic memories (16) to said display controller (20). 5. The subsystem (10) of Claim 1 further comprising means (34) for said plural image generators (14) to have interleaved access to said electronic memories (16) . 6. The subsystem (10) of Claim 1 further comprising means (34) for assigning each electronic memory (16) both physical and logical addresses. 7. The subsystem of Claim 1 wherein said video bus (28) includes a multiplexer (18) for selecting mappings of memories (16) to said display controller (20). 8. The subsystem (10) of Claim 7 further comprising a raster read-out device (22) for providing an image in response to signals from said display controller (20) , said display controller (20) and said ~ ~ multiplexer (18) cooperating to map windows in multiple of said memories (16) to respective viewports on said display. 9. The subsystems (10) of Claim 8 further comprising means (20) for assigning a different color palette to each viewpoint. 10. The subsystem (10) of Claim 1 wherein each said image generator (14) includes a memory interface unit (34) providing for synchronization with said image bus (26) so that no bus transfers are wasted when control of said image bus (26) is transferred from one of said cogenerators (14) to another of said cogenerators (14) .

Inventors: LEDDEN LARRY D, LEDDEN, LARRY, D.
Applicants: HUGHES AIRCRAFT CO, HUGHES AIRCRAFT COMPANY
Application year: 1988
Main classification: G06F15
IPC codes: G06F3, G06T15, G09G1, G09G3, G09G5