Abstract:
A multi-chip module and a chip set that comprises a plurality of the multi-chip modules. The multi-chip module includes a plurality of functional circuits provided on a substrate, the circuits defining a plurality of signal inputs and outputs. A plurality of pins are secured in a single row along the periphery of the substrate and are connected to the inputs and outputs. The pins include a set of 91 signal pins, two ground pins, and a power pin, the signal pins having a configuration complying in number and signal type with the IEEE-P996 Requirements to define an ISA bus. The multi-chip module includes a rectangular housing wherein the pins, in the form of gull wing pins, extend laterally from a peripherally extending wall. The ISA bus pins extend along one side and partially along adjacent sides of the rectangular module. The functional circuits of one embodiment of the module include a CPU, serial interfaces, a parallel interface, a hard drive interface, a floppy disk interface, a keyboard interface, and flash memory. Other multi-chip modules can include a PCMCIA interface, an Ethernet interface, or a display controller.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 08/564,688 filed on Nov. 29, 1995 now U.S. Pat. No. 5,742,844. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a multi-chip module. 
     BACKGROUND OF THE INVENTION 
     The most successful applications of computer technology have been those that people do not see. Microcontrollers and microprocessors govern automotive anti lock braking systems, automatic teller machines, elevators, subway ticket systems, and medical equipment. These hidden computers, otherwise known as embedded systems, permeate our lives. The embedded control market is, in fact, growing significantly faster than the desk top computing market. A major trend is the move from 4- and 8-bit processors to more powerful devices that provide more computing power and enable more &#34;friendly&#34; man-machine interfaces. A study by Desk Top Strategies showed that in 1994 over 320 million 16- and 32-bit embedded control processors were shipped to original equipment manufacturers (OEMs) for use in embedded control applications. In contrast, only 50 million were shipped to desk top computer manufacturers. The compound annual growth rate for 32-bit processors in the embedded market from 1992 to 1997 is projected to be 53 percent, compared with an estimated 32 percent in the desk top market. 
     The area of greatest growth in the embedded control market is the segment of ultra-miniature controllers for portable and transportable instruments. OEMs have indicated a strong interest in developing products with the PC architecture, but have found that size, integration, power, reliability, or cost constraints make existing broad-level products unsuitable for their applications. 
     The Cardio 386 developed by S-Mos Systems comprises a full function, small footprint, X86 computer that includes a CPU, all standard PC-type I/O controllers, PGA graphics, floppy and hard disk drive interfaces, DRAM, flash memory, and transparent power management. It adopts a PC AT architecture which complies with the ISA (industry standard architecture) bus pin configuration. However, it makes use of a unique edge connector comprising a plurality of tracks formed into rows on a card. This is received in a complementary slot for connection to peripheral devices. The use of a connector for connecting the module to a board makes its implementation inherently unreliable since vibrations can compromise the electrical connections between the various tracks forming the pins, and the corresponding contacts of the slot connector. Furthermore, no provision is made for integrating the module with proprietary hardware of OEMs (original equipment manufacturers). 
     Another prior art device is the Northstar III by Micro Module Systems that comprises a multi-chip module, including a Pentium processor, a cache controller, and RAM incorporated in a 349 pin PGA package. Once again, no facility is provided for interfacing with OEM proprietary hardware, Furthermore, the North Star module is packaged in a 349 pin PGA which makes simple direct connection to peripheral devices impossible without complicated track layout design. Therefore it does not allow the module to be simply dropped into an OEM system. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the invention to incorporate a multi-chip module in an ultra-miniature form factor. In particular it is an object of the invention to provide a module the size of a large integrated circuit. 
     It is a further object of the invention to provide an Intel X86 compatible computer module and peripheral controller modules wherein the computer module includes a CPU, I/O (a parallel port and two serial ports), a keyboard interface, a DRAM interface, floppy disk controller, hard disk controller, and flash disk functions based on Intel X86 architecture. Specifically, it is an object of the invention to provide a multi-chip module that provides an OEM (Original Equipment Manufacturer) with the facility for incorporating a feature set that is compatible with IBM PC/AT hardware, software, and bus pin configuration. 
     It is a further object of the invention to provide a module having low power consumption, broad thermal adaptability, low cost, and high reliability by eliminating cables and mounting hardware. 
     It is yet a further object of the invention to provide a module family having identical ISA bus pin configurations to facilitate easy interconnection. 
     It is yet a further object of the invention to provide a development board to form a platform for receiving a multi-chip module of the invention, thereby to provide for the quick development of pilot projects. 
     According to the invention there is provided a multi-chip module comprising a plurality of functional circuits provided on a substrate, the circuits defining a plurality of signal inputs and outputs, and a plurality of module pins secured in a single row along the periphery of the substrate and connected to the inputs and outputs, the module pins including a set of 91 pins, two ground pins, and a power pin, defining an ISA bus means, the signal pins having a configuration complying in number and signal type with the signal pins laid down under the IEEE-P996 specification, and as applied in the ISA (Industry Standard Architecture) requirements. For this reason it will hereinafter be referred as to as the ISA bus. 
     The module can be rectangular in shape, having a first side, a second side opposite the first side, a third side, and a fourth side, and is defined by an upper surface, a lower surface, and a peripheral wall, and wherein the plurality of pins extend from the peripheral wall. 
     The pins of the ISA bus means of the present invention preferably comprise: pin 38 corresponding to signal IOCHCK; pin 39 corresponding to signal SD07; pin 40 corresponding to signal RESETDRV; pin 41 corresponding signal SD06; pin 42 corresponding to signal SD05; pin 43 corresponding to signal IRQ9; pin 44 corresponding to signal SD04; pin 45 corresponding to signal SD03; pin 46 corresponding to signal DRQ2; pin 47 corresponding to signal DRQ2OUT-; pin 48 corresponding to signal SD02; pin 49 corresponding to signal SD01-; pin 50 corresponding to signal 0WS; pin 51 corresponding to signal SD00; pin 52 corresponding to signal IOCHRDY; pin 53 corresponding to signal SBHE-; pin 54 corresponding to signal MEMSC16-; pin 55 corresponding to signal AEN; pin 56 corresponding to signal SMEMW-; pin 57 corresponding to signal LA23; pin 58 corresponding to signal IOCS16-; pin 59 corresponding to signal SA19; pin 60 corresponding to signal SMEMR-; pin 61 corresponding to signal LA22; pin 62 corresponding to signal IRQ10; pin 63 corresponding to signal SA18; pin 64 corresponding to signal IOW-; pin 65 corresponding to signal LA21; pin 66 corresponding to signal IRQ11; pin 67 corresponding to GND; pin 68 corresponding to signal SA17; pin 69 corresponding to signal IOR-; pin 70 corresponding to signal LA20; pin 71 corresponding to signal IRQ12; pin 72 corresponding to signal SA16; pin 73 corresponding to signal DACK3-; pin 74 corresponding to signal LA19; pin 75 corresponding to signal IRQ15; pin 76 corresponding to signal SA15; pin 77 corresponding to signal DRQ3; pin 78 corresponding to signal LA18; pin 79 corresponding to signal IRQ14; pin 80 corresponding to signal SA14; pin 81 corresponding to signal DACK1-; pin 82 corresponding to signal LA17; pin 83 corresponding to signal DACK0-; pin 84 corresponding to signal SA13; pin 85 corresponding to VCC; pin 86 corresponding to signal DRQ1-; pin 87 corresponding to signal MEMR-; pin 88 corresponding to signal DRQ0; pin 89 corresponding to signal SA12; pin 90 corresponding to signal REFRESH-; pin 91 corresponding to signal MEMW-; pin 92 corresponding to signal DACK5-; pin 93 corresponding to signal SA11; pin 94 corresponding to signal SYSCLK; pin 95 corresponding to signal SD08; pin 96 corresponding to signal DRQ5; pin 97 corresponding to signal SA10; pin 98 corresponding to signal IRQ7; pin 99 corresponding to signal IRQ7OUT; pin 100 corresponding to signal SD09; pin 101 corresponding to signal DACK6-; pin 102 corresponding to GND; pin 103 corresponding to signal SA09; pin 104 corresponding to signal IRQ6; pin 105 corresponding to signal IRQ6OUT; pin 106 corresponding to signal SD10; pin 107 corresponding to signal DRQ6; pin 108 corresponding to signal SA08; pin 109 corresponding to signal IRQ5; pin 110 corresponding to signal SD11; pin 111 corresponding to signal DACK7-; pin 112 corresponding to signal SA07; pin 113 corresponding to signal IRQ4; pin 114 corresponding to signal SD12; pin 115 corresponding to signal DRQ7; pin 116 corresponding to signal SA06; pin 117 corresponding to signal IRQ3; pin 118 corresponding to signal SD13; pin 119 corresponding to signal SA05; pin 120 corresponding to signal DACK2-; pin 121 corresponding to signal SD14; pin 122 corresponding to signal MASTER-; pin 123 corresponding to signal SA04; pin 124 corresponding to signal TC; pin 125 corresponding to signal SD15; pin 126 corresponding to signal SA03; pin 127 corresponding to signal BALE; pin 128 corresponding to signal SA02; pin 129 corresponding to signal SA01; pin 130 corresponding to signal OSC; and pin 131 corresponding to signal SA00. 
     The pin of the ISA bus means of the present invention can alternatively comprise: pin 38 corresponding to signal SA00; pin 39 corresponding to signal OSC; pin 40 corresponding to signal SA01; pin 41 corresponding signal SA02; pin 42 corresponding to signal BALE; pin 43 corresponding to signal SA03; pin 44 corresponding to signal SD15; pin 45 corresponding to signal TC; pin 46 corresponding to signal SA04; pin 47 corresponding to signal MASTER-; pin 48 corresponding to signal SD14; pin 49 corresponding to signal DACK2-; pin 50 corresponding to signal SA05; pin 51 corresponding to signal SD13; pin 52 corresponding to signal IRQ3; pin 53 corresponding to signal SA06; pin 54 corresponding to signal DRQ7; pin 55 corresponding to signal SD12; pin 56 corresponding to signal IRQ4; pin 57 corresponding to signal SA07; pin 58 corresponding to signal DACK7-; pin 59 corresponding to signal SD11; pin 60 corresponding to signal IRQ5; pin 61 corresponding to signal SA08; pin 62 corresponding to signal DRQ6; pin 63 corresponding to signal SD10; pin 64 corresponding to signal IRQ6OUT; pin 65 corresponding to signal IRQ6; pin 66 corresponding to signal SA09; pin 67 corresponding to GND; pin 68 corresponding to signal DACK6-; pin 69 corresponding to signal SD09; pin 70 corresponding to signal IRQ7OUT; pin 71 corresponding to signal IRQ7; pin 72 corresponding to signal SA10; pin 73 corresponding to signal DRQ5; pin 74 corresponding to signal SD08; pin 75 corresponding to signal SYSCLK; pin 76 corresponding to signal SA11; pin 77 corresponding to signal DACK5-; pin 78 corresponding to signal MEMW-; pin 79 corresponding to signal REFRESH-; pin 80 corresponding to signal SA12; pin 81 corresponding to signal DRQ0; pin 82 corresponding to signal MEMR-; pin 83 corresponding to signal DRQ1; pin 84 corresponding to signal SA13; pin 85 corresponding to VCC; pin 86 corresponding to signal DACK0-; pin 87 corresponding to signal LA17; pin 88 corresponding to signal DACK1-; pin 89 corresponding to signal SA14; pin 90 corresponding to signal IRQ14; pin 91 corresponding to signal LA18; pin 92 corresponding to signal DRQ3; pin 93 corresponding to signal SA15; pin 94 corresponding to signal IRQ15; pin 95 corresponding to signal LA19; pin 96 corresponding to signal DACK3-; pin 97 corresponding to signal SA16; pin 98 corresponding to signal IRQ12; pin 99 corresponding to signal LA20; pin 100 corresponding to signal IOR-; pin 101 corresponding to signal,SA17; pin 102 corresponding to GND; pin 103 corresponding to signal IRQ11; pin 104 corresponding to signal LA21; pin 105 corresponding to signal IOW-; pin 106 corresponding to signal SA18; pin 107 corresponding to signal IRQ10; pin 108 corresponding to signal LA22; pin 109 corresponding to signal SMEMR-; pin 110 corresponding to signal SA19; pin 111 corresponding to signal IOCS16-; pin 112 corresponding to signal LA23; pin 113 corresponding to signal SMEMW-; pin 114 corresponding to signal AEN; pin 115 corresponding to signal MEMCS16-; pin 116 corresponding to signal SBHE-; pin 117 corresponding to signal IOCHRDY; pin 118 corresponding to signal SD00; pin 119 corresponding to signal 0WS-; pin 120 corresponding to signal SD01; pin 121 corresponding to signal SD02; pin 122 corresponding to signal DRQ2OUT; pin 123 corresponding to signal DRQ2; pin 124 corresponding to signal SD03; pin 125 corresponding to signal SD04; pin 126 corresponding to signal IRQ9; pin 127 corresponding to signal SD05; pin 128 corresponding to signal SD06; pin 129 corresponding to signal RESETDRV; pin 130 corresponding to signal SD07; and pin 131 corresponding to signal IOCHCK-.The ISA bus pins preferably extend along the first side and at least partially along the third and fourth sides. The multi-chip module can include 240 module pins. 
     The functional circuits in a module can include a central processing unit. The functional circuits can further include two serial interfaces, a parallel interface, a hard drive interface, a floppy disk interface, a keyboard interface, and flash memory. 
     Other modules can include functional circuits that include a PCMCIA interface, an Ethernet interface, or a display controller. 
     The substrate can comprise a printed circuit board and the functional circuits comprise semiconductor devices which can be packaged or can be in bare die form secured to the printed circuit board. 
     Further, according to the invention, there is provided a multi-chip module comprising a plurality of functional circuits encapsulated in a rectangular housing, the housing having an upper surface and a lower surface, and a peripheral wall extending along a first side, a second side opposite the first side, a third side, and a fourth side; and a plurality of pins extending laterally from the peripheral wall, wherein the pins include a set of 91 signal pins, two ground pins and a power pin defining an ISA bus means, the signal pins of which comply in number and signal type, with the signal pins laid down under the IEEE-P996, and as applied in the ISA (Industry Standard Architecture) requirements. 
     Still further, according to the invention, there is provided a module family comprising a plurality of functionally different modules, wherein each module has a plurality of pins and the pins of each module include a set of 91 signal pins, two ground pins, and a power pin, defining an ISA bus means, the signal pins of which comply in number and signal type with the signal pins laid down under the IEEE-P996, and as applied in the ISA (Industry Standard Architecture) requirements. 
     Each module can comprise at least one functional circuit encapsulated in a rectangular housing, the housing having an upper surface and a lower surface, and a peripheral wall extending along a first side, a second side opposite the first side, a third side, and a fourth side, and wherein the pins of the module extend laterally from the peripheral wall. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a multi-chip module of the invention; 
     FIG. 2 is a side view of the module of FIG. 1; 
     FIG. 3 is a block diagram of a multi-chip module of the invention; 
     FIGS. 4A and 4B are a schematic representation of the first embodiment of a multi-chip module of the invention indicating the configuration of the pins; 
     FIGS. 5A and 5B are a schematic representation of the alternative embodiment of a multi-chip module of the invention indicating the configuration of the pins; 
     FIG. 6 shows a PC board layout for a development board showing the mounting, site for the module of FIG. 1, and 
     FIG. 7 is a schematic representation of a number of different modules in accordance with the invention connected to each other by means of their ISA buses to form a module family of the invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     A need exists in the field of embedded applications for small, highly reliable computer systems that draw little power, are easy to integrate, have broad thermal adaptability and are relatively inexpensive. Applications for such devices include medical instruments, data logging devices, security systems, test equipment, point-of-sale terminals, communications devices, such as Internet and facsimile machines, and navigational instruments. OEMs (original equipment manufacturers) typically use the Intel X86 architecture since it offers the world&#39;s largest body of hardware and software. The present invention has accordingly been developed to address the problems in the prior art by providing a multi-chip module packaged to resemble a large integrated circuit chip comprising a 240 pin QFP having an overall footprint of 59.54×79.88 mm. The module includes a set of pins constituting a bus for connection to the OEM designer&#39;s proprietary internal hardware. The invention specifically contemplates providing this bus with a configuration complying with the ISA (Industry Standard Architecture) requirements. This will allow the OEM designer quickly to incorporate IBM PC/AT hardware and software and to implement the module in ISA compatible proprietary product designs. The module is now described in greater detail with reference to FIGS. 1 and 2 which show a plan view and a side view, respectively, of the module. 
     The module 10 is a 240 pin QFP with gull wing pins having a 0.762 mm. pitch. The body is rectangular, the one side of which measures 76.2 mm and the overall footprint in this embodiment being 59.54×79.88 mm. The pins themselves are typically 0.5 mm wide, and the dimensions of distances 12 and 14 in FIG. 1 are 3.5 mm for this embodiment. By using a chip-like package in which the pins are formed around the periphery of the module 10 in a single row as illustrated in FIGS. 1 and 2, the module 10 can easily be soldered into place to form a very sturdy, reliable set of connections. Furthermore, tracks can be designed to lead directly from the pins to another device by making use of PC board tracks on one or both surfaces of the PC board without the need for several layers to route the various tracks. Since the pins are soldered directly to the interconnecting tracks, the system has inherent reliability in that it eliminates cables and mounting hardware that could otherwise vibrate loose. As many as half a dozen interconnecting cables, assorted connectors and mounting hardware required with many existing prior art single board computers, are thereby eliminated. 
     The module thus provides an Intel X86 compatible computer in an ultra-miniature form factor that can be integrated as easily as a semiconductor device and provides the full functionality of a desk top computer. As is described in greater detail below, the same concepts of using a chip-like module using a QFP package with gull wing pins and having an ISA compatible bus is extended also to peripheral controller modules. 
     By integrating a full X86 AT-compatible computer onto a proprietary OEM design, the need for multiple boards is eliminated, thereby eliminating cables and mounting hardware. 
     The full compatibility with PC-AT ISA allows for easy integration with low-cost hardware peripherals. The ISA, compliant bus makes it easy to interface with proprietary hardware design. 
     One embodiment of the module 10, having a CPU as one of its functional circuits, is illustrated in FIG. 3 and includes the standard I/O interfaces, serial ports, a parallel port, and floppy and hard disk interfaces allowing standard hardware, cables, and software libraries to be incorporated in the design. The module 10 includes an 80386 SX CPU 20 which is connected to a DRAM bus 22 and an ISA bus 24 by means of core logic 26. The core logic controls AT-compatible DMA controllers, interrupt controllers, and timers/counters. It also controls the AT keyboard controller 28 and the real time clock 30. Two serial ports 32, 34 and a parallel port 36 are provided, as are a floppy disk controller 40 and an IDE hard drive interface 42. In order to facilitate total solid state operation, internal flash memory 44 is provided that is controlled by a solid state flash disk controller 46. Power is controlled by means of a power monitor 48 that provides a power saving function by controlling CPU sleep modes, and by a watch dog timer 50. The watch dog timer 50 monitors CPU cycles to detect interrupts in the cycle thereby allowing the system to be automatically reset after a predetermined time delay. 
     The microprocessor and various controllers and interfaces comprise chips, optionally in die form, mounted on a multi-layer PC board, e.g. ten-layers. The CPU 20 can be a standard 33 MHz 80386 SX CPU having a DRAM controller for supporting up to 16 M bytes of DRAM. Alternatively, CPU20 can be another standard microprocessor chip such as another type of 80386 chip or die, a 80486 chip or die, a Pentium chip or die, or any other desired microprocessor which is capable of providing the function of the 80386 device. 
     The standard DRAM interface provides all the signals for connecting standard page-mode DRAMs of various configurations, including standard 8- and 9-bit 30-pin SIMM modules and discrete components, such as standard 1 M×4 and 4 M×4 DRAM chips. The interface is designed to support 70 ns or faster DRAMs. 
     The DRAM interface consists of: 
     Multiplexed addresses MA00-MA10 
     Bi-directional data D0-D15 
     Column Address Strobes CASL0- to CASL3- (low byte) 
     CASH0- to CASH3- (high byte) 
     Row Address Strobes RAS0- to RAS3- 
     Memory Write Strobe DRWE- 
     The serial ports 32, 34 are PC-compatible asynchronous serial ports, typically treated as COM 1 and COM 2 devices by DOS. 
     
         ______________________________________Serial     Typical I/O           StandardPort       Usage   Address       Interrupt______________________________________Serial 1   COM1    3F8-3FF       IRQ4Serial 2   COM2    2F8-2FF       IRQ3______________________________________ 
    
     Either or both serial ports can be disabled using SETUP. When disabled, the port*s I/O address and interrupt are made available for other expansion devices on the PC bus. 
     A full complement of input and output handshaking lines are supported by the serial ports, and all serial port signals are at standard LSTTL levels. In another embodiment, RS232C signal compatibility can be achieved by including a TTL-RS232C level converter to provide the necessary bipolar signal levels. The parallel port is a fully-compatible PC/AT parallel port providing bi-directional operation. It is typically used to support a line printer. As appears from the table below: 
     
         ______________________________________Parallel    Typical I/O           StandardPort        Usage   Address       Interrupt______________________________________Parallel 1  LPT1    378H-37FH     IRQ7______________________________________ 
    
     4.7K-ohm pull-ups (+5V) are typically provided to the following parallel port signals: 
     STROBE- 
     SLIN- 
     INIT- 
     AUTOFD- 
     Generally, if the parallel port will be connected to a cable for high speed data communication (as opposed to static digital output levels or static TTL level sensing), certain signals require a 2.2 nF capacitor connected to ground. 
     These include: 
     PD0-PD7 
     STRB- 
     Parallel port registers are provided for the parallel port as appears from the table set out below: 
     
         ______________________________________Parallel Port Registers                                    D                                    B2                                    5F           Signal            Active PiRegister   Bit     Name       In/Out High/Low                                    n______________________________________DATA    0       PD0        I/O    HIGH    2(A + 0) 1       PD1        I/O    HIGH    3   2       PD2        I/O    HIGH    4   3       PD3        I/O    HIGH    5   4       PD4        I/O    HIGH    6   5       PD5        I/O    HIGH    7   6       PD6        I/O    HIGH    8   7       PD7        I/O    HIGH    9STATUS  0       1          --     --     --(A + 1))   1       1          --     --     --   2       1          --     --     --   3       ERROR-     IN     LOW    15   4       SLCT-      IN     HIGH   13   5       PE         IN     HIGH   12   6       ACK-       IN     HIGH   10   7       BUSY       IN     LOW    11CONTROL 0       STRB-      OUT    LOW     1(A + 2) 1       AUTOFD-    OUT    LOW    14   2       INIT-      OUT    HIGH   16   3       SLCTIN-    OUT    LOW    17   4       IRQ ENABLE --     HIGH   --   5       1          --     --     --   6       1          --     --     --   7       1          --     --     --______________________________________ 
    
     The DOS-compatible floppy drive interface 40 allows cable connections for up to four floppy drives. In PC-compatible systems, the BIOS and DOS support two drives. These are configured using the BIOS SETUP function. Hardware controls for two additional drives are provided. 
     The floppy drive interface supports the following standard floppy formats: 
     
         ______________________________________Capacity  Drive Size   Tracks  Data Rate______________________________________360K      51/4 inch    40      250 KHz1.2M      51/4 inch    80      500 KHz720K      31/2 inch    80      250 KHz1.44M     31/2 inch    80      500 KHz______________________________________ 
    
     The various floppy interface resources are given in the table below 
     
         ______________________________________Floppy Interface ResourcesResource     Function______________________________________I/O Address  3F2 FDC Digital Output Register (LDOR)3F0h-3F7h    3F4 FDC Main Status Register        3F5 FDC Data Register        3F7 FDC Control Register (LDCR)IRQ6         InterruptDRQ2BDACK2   DMA Controller Channel______________________________________ 
    
     Outputs to the floppy drive and from the floppy drive are Aopen collector=. Pull-up resistors are therefore required for proper termination, both on the SMX/386 board and on one of the attached floppy drives (not both). 
     330-Ohm pull-ups are required for the following floppy interface signals: 
     DSKCHG- 
     RDATA- 
     WRPRT- 
     TRK0- 
     INDEX- 
     The pin numbers and functions associated with the floppy drive are given in the table below: 
     
         ______________________________________Floppy Drive Interface FloppyPin   Pin       Signal Name                      Function   In/Out______________________________________11     2        DENSEL     Speed/Precomp  4        N/A                   N/A  6        N/S        Key pin    N/A12     8        INDEX-     Index Pulse                                 IN13    10        MTR0-      Motor On 0 OUT15    12        DRV1-      Drive Select 2                                 OUT18    14        DRV0-      Drive Select 1                                 OUT20    16        MTR1-      Motor On 1 OUT22    18        DIR-       Direction Select                                 OUT23    20        STEP-      Step Pulse OUT24    22        WDATA-     Write Data OUT25    24        WGATE-     Write Gate OUT26    26        TRK0-      Track 0    INPUT27    28        WRPRT-     Write Protect                                 INPUT28    30        RDATA-     Read Data  INPUT29    32        HDSEL-     Head Select                                 OUT30    34        DSKCHG-    Disk Change                                 INPUT 1B33      Ground     Ground______________________________________ 
    
     The IDE hard drive interface 42 is a standard interface used in PC-compatible systems for hard disk drives. Up to two drives can be connected in a master-slave arrangement. The resources are depicted in the table below: 
     
         ______________________________________IDE Hard Disk ResourcesResource           Function______________________________________I/O Address        Hard Disk Interface1F0h-1F7hIRQ14              Interrupt______________________________________ 
    
     The IDE interface pins are arranged to easily attach to a male PC-mounted ribbon-cable connector, the IDE drives typically being attached to the drive interface using a 40-pin ribbon cable. 
     The pin configuration for the IDE interface is given in the table below: 
     
         ______________________________________IDE Drive InterfaceIDEPin  Pin      Signal Name                    Function     In/Out______________________________________223   1       HDRESET-   Reset signal from host                                 OUT 2       GND        Ground       OUT224   3       IDED07     Data bit 7   I/O225   4       HDD08      Data bit 8   I/O226   5       HDD06      Data bit 6   I/O227   6       HDD09      Data bit 9   I/O228   7       HDD05      Data bit 5   I/O229   8       HDD10      Data bit 10  I/O230   9       HDD04      Data bit 4   I/O231  10       HDD11      Data bit 11  I/O232  11       HDD03      Data bit 3   I/O233  12       HDD12      Data bit 12  I/O234  13       HDD02      Data bit 2   I/O235  14       HDD13      Data bit 13  I/O236  15       HDD01      Data bit 1   I/O237  16       HDD14      Data bit 14  I/O238  17       HDD00      Data bit 0   I/O239  18       HDD15      Data bit 15  I/O19       GND        Ground       OUT20       KEY        Keyed pin    N/C21       N/A        Reserved     N/C22       GND        Ground       OUT240  23       HDIOW-     Write strobe OUT24       GND        Ground       OUT 1   25       HDIOR-     Read strobe  OUT26       GND        Ground       OUT27       RSVD       Reserved     N/C 2   28       HDALE      Address latch enable                                 OUT29       RSVD       Reserved     N/C30       GND        Ground       OUT237  31       HDD14      Drive interrupt request                                 IN______________________________________ 
    
     One embodiment of the pin configuration for the module 10 as a whole is illustated in FIGS. 4A and 4B are given in the pin description table below: 
     
         ______________________________________Pin  Pin Name  Description            Type______________________________________ 1   HDIOR-    IDE I/O Read, active low, Buffered version                                 O24          of IOR 2   HDALE     IDE Address Latch Enable, active high.                                 O24          Buffered version of BALE 3   IRQ14     IDE Interrupt Request 14. For use with IDE                                 I          interface. Same signal appears on pin 90. 4   IOCS16    IDE I/O Chip Select 16. A low requests a                                 I          16-bit transfer on the SA bus. Same signal          appears on pin 238. This one is used for the          IDE interface. 5   HDA1      IDE Address 1. Buffered version of SA1.                                 O24 6   HDA0      IDE Address 0. Buffered version of SA0                                 O24 7   HDA2      IDE Address 2. Buffered version of SA2                                 O24 8   HDCS-     IDE Chip Select. A low indicates that data                                 O24          being transferred to or from the IDE drive. 9   FDCS-     Floppy disk Chip Select. A low indicates                                 O24t          data is being transferred to or from the          floppy disk. 10  LEDIN     LED signal from IDE drive                                 I 11  DENSEL 12  INDEX-    Floppy disk index pulse, input from drive                                 I 13  MTR0-     Floppy disk active lower open drain output          selects motor driver 0. The motor enable          bits are software controlled via the          floppy&#39;s Digital Output Register (DOR). 14  MTR2-     Floppy disk active low open drain output          selects motor driver 2. The motor enable          bits are software controlled via the          floppy&#39;s Digital Output Register (DOR). 15  DRV1-     Floppy disk active lower open drain output          that selects floppy drive 1 16  DRV3-     Floppy disk active low open drain output          that selects floppy drive 3 17  GND 18  DRV0-     Floppy disk active low open drain output          that selects floppy drive 0 19  DRV2-     Floppy disk active low open drain output          that selects floppy drive 2 20  MTR1-     Floppy disk active low open drain output          selects motor driver 1. The motor enable bits          are software controlled via the floppy&#39;s          Digital Output Register (DOR). 21  MTR3-     Floppy disk active low open drain output          selects motor driver 3. The motor enable bits          are software controlled via the floppy&#39;s          Digital Output Register (DOR). 22  DIR       Floppy disk open drain output that controls          floppy read/write head movement direction.          Low=set pin. 23  STEP-     Floppy disk active low output provides the          step pulse to move the floppy read/write          head 24  WDATA-    Floppy disk active lower signal writes          precompensated serial data to the selected          floppy drive. This is a high open current          drain output and is gated internally with          WGATE-. 25  WGATE-    Floppy disk active low open drain signal          that enables the head to write onto the          floppy disk. 26  TRK0-     Floppy disk active lower Schmitt input                                 IS          indicates that the head is on track 0 of          the selected drive 27  WRPRT-    Floppy disk active low Schmitt input                                 IS          indicating that the disk is write protected.          Any WDATA- command is ignored. 28  RDATA-    Floppy disk active lower Schmitt input that                                 IS          reads raw data from the floppy disk. 29  HDSEL     Floppy disk open drain output that selects the          head on the selected drive. Low=side 0. 30  DSKCHG    Floppy disk input signal indicating that                                 Ihe          floppy door has been opened. 31  5VBB 32  GND 33  PFI       Powerfail 34  PFO       Powerfail 35  MR-       Powerfail 36  RTCIRQ-   Alarm output from the onboard real time          clock 37  WDO       Watchdog timer 38  SA00      ISA System Address 00  O24 39  OSC       ISA 14.318 MHz clock. This clock is          asynchronous to all other system clocks 40  SA01      ISA System Address 01  O24 41  SA02      ISA System Address 02  O24 42  BALE      ISA Buffered Address Latch Enable 43  SA03      ISA System Address 03  O24 44  SD15      ISA System Data 15 45  TC        ISA DMA Terminal Court 46  SA04      ISA System Address 04  O24 47  MASTER-   ISA 48  SD14      ISA System Data 14 49  DACK2-    ISA DMA 2 Acknowledge strobe 50  SA05      ISA System Address 05  O24 51  SD13      ISA System Data 13 52  IRQ3      ISA Interrupt Request 3                                 I 53  SA06      ISA System Address 06  O24 54  DRQ7      ISA DMA 7 Request      I 55  SD12      ISA System Data 12 56  IRQ4      ISA Interrupt Request 4                                 I 57  SA07      ISA System Address 07  O24 58  DACK7-    ISA DMA 7 Acknowledge strobe 59  SD11      ISA System Data 11 60  IRQ5      ISA Interrupt Request 5                                 I 61  SA08      ISA System Address 08  O24 62  DRQ6      ISA DMA 6 Request      I 63  SD10      ISA System Data 10 64  IRQ6OUT   Floppy disk interrupt request. Normally          connects to IRQ6 (pin 65) 65  IRQ6      ISA Interrupt Request 6                                 I 66  SA09      ISA System Address 09  O24 67  GND 68  DACK6-    ISA DMA 6 Acknowledge strobe 69  SD09      ISA System Data 09 70  IRQ7OUT   Parallel port interrupt request. Normally          connects to IRQ7 (pin 71). 71  IRQ7      ISA Interrupt Request 7                                 I 72  SA10      ISA System Address 10  O24 73  DRQ5      ISA DMA 5 Request      I 74  SD08      ISA System Data 08 75  SYSCLK    ISA System Clock 76  SA11      ISA System Address 11  O24 77  DACK5-    ISA DMA 5 Acknowledge strobe 78  MEMW-     ISA active low memory write strobe 79  REFRESH-  ISA active low signal indicating current bus          cycle is a memory refresh 80  SA12      ISA System Address 12  O24 81  DRQ0      ISA DMA 0 Request      I 82  MEMR-     ISA active low memory read strobe 83  DRQ1      ISA DMA 1 Request      I 84  SA13      ISA System Address 13  O24 85  VCC 86  DACK0-    ISA DSMA 0 Acknowledge strobe 87  LA17      ISA Latched Address 17 O24 88  DACK1-    ISA DMA 1 Acknowledge strobe 89  SA14      ISA System Address 14  O24 90  IRQ14     ISA Interrupt Request 14, normally used                                 I          for IDE interface 91  LA18      ISA Latched address 18 O24 92  DRQ3      ISA DMA 3 Request strobe 93  SA15      ISA System Address 15  O24 94  IRQ15     ISA Interrupt Request 15                                 I 95  LA19      ISA Latched Address 19 O24 96  DACK3-    ISA DMA 3 Acknowledge strobe 97  SA16      ISA System Address 16  O24 98  IRQ12     ISA Interrupt Request 12                                 I 99  LA20      ISA Latched Address 20 O24100  IOR-      ISA I/O Read strobe101  SA17      ISA System Address 17  O24102  GND103  IRQ11     ISA Interrupt Request 11                                 I104  LA21      ISA Latched Address 21 O24105  IOW-      ISA I/O Write strobe106  SA18      ISA System Address 18  O24107  IRQ10     ISA Interrupt Request 10                                 I108  LA22      ISA Latched Address 22 O24109  SMEMR-    ISA System Memory Read strobe110  SA19      ISA System Address 19  O24111  IOCS16-   ISA 16-bit I/O Chip Select request. Indicates                                 I          that the current I/O transaction is 16-bits.112  LA23      ISA Latched Address 23 O24113  SMEMW-    ISA System Memory Write strobe114  AEN       ISA Address Enable115  MEMCS16-  ISA 16-bit Memory Chip Select request.                                 I          Indicates that the current memory transaction          is 16-bits.116  SBHE-     ISA System Byte High Enable117  IOCHRDY   ISA I/O Channel Ready. A low adds wait                                 I          states to the current ISA bus cycle118  SD00      ISA System Data 00119  OWS       ISA active low causing current memory                                 I          cycle to be completed without additional          wait states.120  SD01      ISA System Data 01121  SD02      ISA System Data 02122  DRQ2OUT   Floppy DMA 2 Request. Normally          connected to DRQ2 (pin 123)123  DRQ2      ISA DMA 2 Request strobe                                 I124  SD03      ISA System Data 03125  SD04      ISA System Data 04126  IRQ9      ISA Interrupt Request 09                                 I127  SD05      ISA System Data 05128  SD06      ISA System Data 06129  RESETDR   ISA active high system reset signalV130  SD07      ISA System Data 07131  IOCHCHK-  ISA gated non-maskable interrupt input                                 I132  HISPEED   Input to select CPU speed. High=high speed.                                 I133  SPKR      Speaker output134  KDATA     Keyboard data135  KCLOCK    Keyboard clock136  PWRDN-137  GND138  COLOR     Video Color/Mono jumper                                 I139  KBLOCK    Keyboard lock. Low blocks keyboard input                                 I140  SLCT      Parallel Port141  PE        Parallel Port142  BUSY      Parallel Port143  ACK-      Parallel Port144  PD7       Parallel Port Data 7145  PD6       Parallel Port Data 6146  PD5       Parallel Port Data 5147  PD4       Parallel Port Data 4148  PD3       Parallel Port Data 3149  SLCTIN-   Parallel Port150  PD2       Parallel Port Data 2151  INIT-     Parallel Port152  PD1       Parallel Port Data 1153  ERR-      Parallel Port154  GND155  PD0       Parallel Port Data 0156  AUTOFD    Parallel Port157  STRB-     Parallel Port158  DCD2      Serial Port 2 Data Carrier Detect159  DSR2      Serial Port 2 Data Set Ready160  RXD2      Serial Port 2 Receive Data161  RTS2      Serial Port 2 Request To Send162  TXD2      Serial Port 2 Transmit Data163  CTS2      Serial Port 2 Clear To Send164  DTR2      Serial Port 2 Data Terminal Ready165  R12       Serial Port 2 Ring Indicator166  DCD1      Serial Port 1 Data Carrier Detect167  DSR1      Serial Port 1 Data Set Ready168  RXD1      Serial Port 1 Receive Data169  RTS1      Serial Port 1 Request to Send170  TXD1      Serial Port 1 Transmit Data171  CTS1      Serial Port 1 Clear to Send172  DTR1      Serial Port 1 Data Terminal Ready173  RI1       Serial Port 1 Ring Indicator174  GAMECS175  RAS3-     DRAM Row Address Strobe 3176  RAS2-     DRAM Row Address Strobe 2177  RAS1-     DRAM Row Address Strobe 1178  RAS0-     DRAM Row Address Strobe 0179  DP1       DRAM parity bit for high byte memory180  DP0       DRAM parity bit for low byte memory181  D15       DRAM Data Bit 15182  D07       DRAM Data Bit 7183  D14       DRAM Data Bit 14184  D06       DRAm Data Bit 6185  DRWE-     DRAM memory write strobe186  D13       DRAM Data Bit 13187  GND188  D05       DRAM Data Bit 5189  MA10      DRAM multiplexed memory address 10190  MA09      DRAM multiplexed memory address 9191  MA08      DRAM multiplexed memory address 8192  D12       DRAM Data Bit 12193  D04       DRAM Data Bit 4194  MA07      DRAM multiplexed memory address 7195  MA06      DRAM multiplexed memory address 6196  D11       DRAM Data Bit 11197  D03       DRAM Data Bit 3198  MA05      DRAM multiplexed memory address 5199  MA04      DRAM multiplexed memory address 4200  D10       DRAM Data Bit 10201  D01       DRAM Data Bit 2202  MA03      DRAM multiplexed memory address 3203  MA02      DRAM multiplexed memory address 2204  D09       DRAM Data Bit 9205  VCC206  D01       DRAM Data Bit 1207  MA01      DRAM multiplexed memory address 1208  MA00      DRAM multiplexed memory address 0209  D08       DRAM Data Bit 8210  D00       DRAM Data Bit 0211  CASH3-    DRAM Column Address Strobe, High byte 3212  CASL3-    DRAM Column Address Strobe, Low byte 3213  CASH2-    DRAM Column Address Strobe, High byte 2214  CASL2-    DRAM Column Address Strobe, Low byte 2215  CASH1-    DRAM Column Address Strobe, High byte 1216  CASL1-    DRAM Column Address Strobe, Low byte 1217  CASH0-    DRAM Column Address Strobe, High byte 0218  CASL0-    DRAM Column Address Strobe, Low byte 0219  BDIS220  XROMCS-221  LEDOUT-222  GND223  HDRESET-  IDE224  IDED07    IDE Data Bit 7225  HDD08     IDE Data Bit 8226  HDD06     IDE Data Bit 6227  HDD09     IDE Data Bit 9228  HDD05     IDE Data Bit 5229  HDD10     IDE Data Bit 10230  HDD04     IDE Data Bit 4231  HDD11     IDE Data Bit 11232  HDD03     IDE Data Bit 3233  HDD12     IDE Data Bit 12234  HDD02     IDE Data Bit 2235  HDD13     IDE Data Bit 13236  HDD01     IDE Data Bit 1237  HDD14     IDE Data Bit 14238  HDD00     IDE Data Bit 0239  HDD15     IDE Data Bit 15240  HDIOW-    IDE buffered I/O Write strobe______________________________________ 
    
     As mentioned above, the core logic 26 supports a DRAM bus 22 and an ISA compatible expansion bus 24 complying in number and signal type with the IEEE-P996 requirements (and corresponding to the ISA (Industry Standard Architecture) requirements). The pin configuration for the expansion bus 24 is given in the table below with corresponding pin numbers for expansion bus connectors A, B, C, D. The bus 24 comprises 94 pins that includes VCC and two GND pins. 
     
         ______________________________________                            In/  Cur-Pin    Signal Name                 Function   Out  rent Load*______________________________________38   A31    SA00      Address bit 0                            I/O  12   PU                                 mA39   B30    OSC       14.318 MHz clock                            Out  6 mA 33 SER40   A30    SA01      Address bit 1                            I/O  12   PU                                 mA41   A29    SA02      Address bit 2                            I/O  12   PU                                 mA42   B28    BALE      Address latch enable                            Out  12                                 mA43   A28    SA03      Address bit 3                            I/O  12   PU                                 mA44   C18    SD15      System Data bit 15                            I/O  12   PU                                 mA45   B27    TC        DMA Terminal                            Out  4 mA                 Count46   A27    SA04      Address bit 4                            I/O  12   PU                                 mA47   D17    MASTER-   Bus master assert                            In   N/A  330 PU48   C17    SD14      System Data bit 14                            I/O  24   PU                                 mA49   B26    DACK2-    DMA Acknowledge                            Out  4 mA                 250   A26    SA05      Address bit 5                            I/O  12   PU                                 mA51   C16    SD13      System Data bit 13                            I/O  24   PU                                 mA52   B25    IRQ3      Interrupt Request 3                            In   N/A  PU53   A25    SA06      Address bit 6                            I/O  12   PU                                 mA54   D15    DRQ7      DMA Request 7                            In   N/A  PD55   C15    SD12      System Data bit 12                            I/O  24   PU                                 mA56   B24    IRQ4      Interrupt Request 4                            In   N/A  PU57   A24    SA07      Address bit 7                            I/O  12   PU                                 mA58   D14    DACK7-    DMA Acknowledge                            Out  4 mA                 759   C14    SD11      System Data bit 11                            I/O  24   PU                                 mA60   B23    IRQ5      Interrupt Request 5                            In   N/A  PU61   A23    SA08      Address bit 8                            I/O  12   PU                                 mA62   D13    DRQ6      DMA Request 6                            In   N/A  PD63   C13    SD10      System Data bit 10                            I/O  24   PU                                 mA64          IRQ6OUT   Floppy Disk                 Interrupt Request65   B22    IRQ6      Interrupt Request 6                            In   N/A  PU66   A22    SA09      Address bit 9                            I/O  12   PU                                 mA67          GND68   D12    DACK6-    DMA Acknowledge                            Out  4 mA                 669   C12    SD9       System Data bit 9                            I/O  24   PU                                 mA70          IRQ7OUT   Parallel Port                 Interrupt Request71   B21    IRQ7      Interrupt Request 7                            In   N/A  PU72   A21    SA10      Address bit 10                            I/O  12   PU                                 mA73   D11    DRQ5      DMA Request 5                            In   N/A  PD74   C11    SD08      System Data bit 8                            I/O  24   PU                                 mA75   B20    SYSCLK    System clock (8                            Out  12                 MHz)            mA76   A20    SA11      Address bit 11                            I/O  12   PU                                 mA77   D10    DACK5-    DMA Acknowledge                            Out  4 mA                 578   C10    MEMW-     Memory Write                            I/O  6 mA PU, 33                                      SER79   B19    REFRESH-  Memory Refresh                            I/O  6 mA 470 PU,                                      33 SER80   A19    SA12      Address bit 12                            I/O  12   PU                                 mA81   D9     DRQ0      DMA Request 0                            In   N/A  PD82   C9     MEMR-     Memory Read                            I/O  6 mA PU, 33                                      SER83   B18    DRQ1      DMA Request 1                            In   N/A  PD84   A18    SA13      Address bit 13                            I/O  12   PU                                 mA85          VCC86   D8     DACK0-    DMA Acknowledge                            Out  4 mA                 087   C8     LA17      Address bit 17                            I/O  24                                 mA88   B17    DACK1-    DMA Acknowledge                            Out  4 mA                 189   A17    SA14      Address bit 14                            I/O  12   PU                                 mA90   D7     IRQ14     Interrupt Request 14                            In   N/A  PU91   C7     LA18      Address bit 18                            I/O  24                                 mA92   B16    DRQ3      DMA Request 3                            In   N/A  PD93   A16    SA15      Address bit 15                            I/O  12   PU                                 mA94   D6     IRQ15     Interrupt Request 15                            In   N/A  PU95   C6     LA19      Address bit 19                            I/O  24                                 mA96   B15    DACK3-    DMA Acknowledge                            Out  4 mA                 397   A15    SA16      Address bit 16                            I/O  12   PU                                 mA98   D5     IRQ12     Interrupt Request 12                            In   N/A  PU99   C5     LA20      Address bit 20                            I/O  24                                 mA100  B14    IOR-      I/O Read   I/O  6 mA PU101  A14    SA17      Address bit 17                            I/O  12   PU102         GND                       mA103  D4     IRQ11     Interrupt Request 11                            In   N/A  PU104  C4     LA21      Address bit 21                            I/O  24                                 mA105  B13    IOW-      I/O Write  I/O  6 mA PU106  A13    SA18      Address bit 18                            I/O  12   PU                                 mA107  D3     IRQ10     Interrupt Request 10                            In   N/A  PU108  C3     LA22      Address bit 22                            I/O  24                                 mA109  B12    SMEMR-    Mem Read (lower                            I/O  6 mA 33 SER                 IMB)110  A12    SA19      Address bit 19                            I/O  12   PU                                 mA111  D2     IOCS16-   16-bit I/O access                            In   N/A  330 PU112  C2     LA23      Address bit 23                            I/O  24                                 mA113  B11    SMEMW-    Mem Write (lower 1                            I/O  6 mA 33 SER                 MB)114  A11    AEN       Address Enable                            I/O  12   PU                                 mA115  D1     MEMCS16-  16-bit mem access                            In   N/A  330 PU116  C1     SBHE-     Bus High Enable                            I/O  12   PU                                 mA117  A10    IOCHRDY   Processor Ready                            In   N/A  1K PU                 Ctrl118  A9     SD00      System Data bit 0                            I/O  24   PU                                 mA119  B8     ENDXFR-   Zero wait state                            In   N/A  330 PU       (OWS-)120  A8     SD01      System Data bit 1                            I/O  24   PU                                 mA121  A7     SD02      System Data bit 2                            I/O  24   PU                                 mA122         DRQ2OUT   Floppy DMA 2                 Request123  B6     DRQ2      DMA request 2                            In   N/A  PD124  A6     SD03      System Data bit 3                            I/O  24   PU                                 mA125  A5     SD04      System Data bit 4                            I/O  24   PU                                 mA126  B4     IRQ9      Interrupt request 9                            In   N/A  PU127  A4     SD05      System Data bit 5                            I/O  24   PU                                 mA128  A4     SD06      System Data bit 6                            I/O  24   PU                                 mA129  B2     RESETDRV  System reset signal                            Out  24                                 mA130  A2     SD07      System Data bit 7                            I/O  24   PU                                 mA131  A1     IOCHCK-   Sub NMI input                            In   N/A  4.7K                                      PU______________________________________ 
    
     An alternative embodiment of the pin configuration for the module 10 as a whole is rated in FIGS. 5A and 5B are given in the pin description table below: 
     
         ______________________________________Pin  Pin Name  Description            Type______________________________________ 1   HDIOR-    IDE I/O Read, active low, Buffered version                                 O24          of IOR 2   HDALE     IDE Address Latch Enable, active high.                                 O24          Buffered version of BALE 3   IRQ14     IDE Interrupt Request 14. For use with IDE                                 I          interface. Same signal appears on pin 90. 4   IOCS16-   IDE I/O Chip Select 16. A low requests a                                 I          16-bit transfer on the SA bus. Same signal          appears on pin 238. This one is used for the          IDE interface. 5   HDA1      IDE Address 1. Buffered version of SA1.                                 O24 6   HDA0      IDE Address 0. Buffered version of SA0                                 O24 7   HDA2      IDE Address 2. Buffered version of SA2                                 O24 8   HDCS-     IDE Chip Select. A low indicates that data                                 O24          being transferred to or from the IDE drive. 9   FDCS-     Floppy disk Chip Select. A low indicates                                 O24t          data is being transferred to or from the          floppy disk. 10  LEDIN     LED signal from IDE drive                                 I 11  DENSEL 12  INDEX-    Floppy disk index pulse, input from drive                                 I 13  MTR0-     Floppy disk active lower open drain output          selects motor driver 0. The motor enable          bits are software controlled via the          floppy&#39;s Digital Output Register (DOR). 14  MTR2-     Floppy disk active low open drain output          selects motor driver 2. The motor enable          bits are software controlled via the          floppy&#39;s Digital Output Register (DOR). 15  DRV1-     Floppy disk active lower open drain output          that selects floppy drive 1 16  DRV3-     Floppy disk active low open drain output          that selects floppy drive 3 17  GND 18  DRV0-     Floppy disk active low open drain output          that selects floppy drive 0 19  DRV2-     Floppy disk active low open drain output          that selects floppy drive 2 20  MTR1-     Floppy disk active low open drain output          selects motor driver 1. The motor enable bits          are software controlled via the floppy&#39;s          Digital Output Register (DOR). 21  MTR3-     Floppy disk active low open drain output          selects motor driver 3. The motor enable bits          are software controlled via the floppy&#39;s          Digital Output Register (DOR). 22  DIR       Floppy disk open drain output that controls          floppy read/write head movement direction.          Low=set pin. 23  STEP-     Floppy disk active low output provides the          step pulse to move the floppy read/write          head 24  WDATA-    Floppy disk active lower signal writes          precompensated serial data to the selected          floppy drive. This is a high open current          drain output and is gated internally with          WGATE-. 25  WGATE-    Floppy disk active low open drain signal          that enables the head to write onto the          floppy disk. 26  TRK0-     Floppy disk active lower Schmitt input                                 IS          indicates that the head is on track 0 of          the selected drive 27  WRPRT-    Floppy disk active low Schmitt input                                 IS          indicating that the disk is write protected.          Any WDATA- command is ignored. 28  RDATA-    Floppy disk active lower Schmitt input that                                 IS          reads raw data from the floppy disk. 29  HDSEL     Floppy disk open drain output that selects the          head on the selected drive. Low=side 0. 30  DSKCHG    Floppy disk input signal indicating that                                 Ihe          floppy door has been opened. 31  5VBB 32  GND 33  PFI       Powerfail 34  PFO       Powerfail 35  MR-       Powerfail 36  RTCIRQ-   Alarm output from the onboard real time          clock 37  WDO       Watchdog timer 38  IOCHCK    ISA System Address 00  O24 39  SD07      ISA 14.318 MHz clock. This clock is          asynchronous to all other system clocks 40  RESETDRV  ISA System Address 01  O24 41  SD06      ISA System Address 02  O24 42  SD05      ISA Buffered Address Latch Enable 43  IRQ9      ISA System Address 03  O24 44  SD04      ISA System Data 15 45  SD03      ISA DMA Terminal Court 46  DRQ2      ISA System Address 04  O24 47  DRQ2OUT-  ISA 48  SD02      ISA System Data 14 49  SD01-     ISA DMA 2 Acknowledge strobe 50  OWS       ISA System Address 05  O24 51  SD00      ISA System Data 13 52  IOCHRDY   ISA Interrupt Request 3                                 I 53  SBHE-     ISA System Address 06  O24 54  MEMCS16-  ISA DMA 7 Request      I 55  AEN       ISA System Data 12 56  SMEMW-    ISA Interrupt Request 4                                 I 57  LA23      ISA System Address 07  O24 58  IOCS16-   ISA DMA 7 Acknowledge strobe 59  SA19      ISA System Data 11 60  SMEMR-    ISA Interrupt Request 5                                 I 61  LA22      ISA System Address 08  O24 62  IRQ10     ISA DMA 6 Request      I 63  SA18      ISA System Data 10 64  IOW-      Floppy disk interrupt request. Normally          connects to IRQ6 (pin 65) 65  LA21      ISA Interrupt Request 6                                 I 66  IRQ11     ISA System Address 09  O24 67  GND 68  SA17      ISA DMA 6 Acknowledge strobe 69  IOR-      ISA System Data 09 70  LA20      Parallel port interrupt request. Normally          connects to IRQ7 (pin 71). 71  IRQ12     ISA Interrupt Request 7                                 I 72  SA16      ISA System Address 10  O24 73  DACK3-    ISA DMA 5 Request      I 74  LA19      ISA System Data 08 75  IRQ15     ISA System Clock 76  SA15      ISA System Address 11  O24 77  DRQ3      ISA DMA 5 Acknowledge strobe 78  LA18      ISA active low memory write strobe 79  IRQ14     ISA active low signal indicating current bus          cycle is a memory refresh 80  SA14      ISA System Address 12  O24 81  DACK1-    ISA DMA 0 Request      I 82  LA17      ISA active low memory read strobe 83  DACK0-    ISA DMA 1 Request      I 84  SA13      ISA System Address 13  O24 85  VCC 86  DRQ1-     ISA DSMA 0 Acknowledge strobe 87  MEMR-     ISA Latched Address 17 O24 88  DRQ0      ISA DMA 1 Acknowledge strobe 89  SA12      ISA System Address 14  O24 90  REFRESH-  ISA Interrupt Request 14, normally used                                 I          for IDE interface 91  MEMW-     ISA Latched address 18 O24 92  DACK5-    ISA DMA 3 Request strobe 93  SA11      ISA System Address 15  O24 94  SYSCLK    ISA Interrupt Request 15                                 I 95  SD08      ISA Latched Address 19 O24 96  DRQ5      ISA DMA 3 Acknowledge strobe 97  SA10      ISA System Address 16  O24 98  IRQ7      ISA Interrupt Request 12                                 I 99  IRQ7OUT   ISA Latched Address 20 O24100  SD09      ISA I/O Read strobe101  DACK6-    ISA System Address 17  O24102  GND103  SA09      ISA Interrupt Request 11                                 I104  IRQ6      ISA Latched Address 21 O24105  IRQ6OUT   ISA I/O Write strobe106  SD10      ISA System Address 18  O24107  DRQ6      ISA Interrupt Request 10                                 I108  SA08      ISA Latched Address 22 O24109  IRQ5      ISA System Memory Read strobe110  SD11      ISA System Address 19  O24111  DACK7-    ISA 16-bit I/O Chip Select request. Indicates                                 I          that the current I/O transaction is 16-bits.112  SA07      ISA Latched Address 23 O24113  IRQ4      ISA System Memory Write strobe114  SD12      ISA Address Enable115  DRQ7      ISA 16-bit Memory Chip Select request.                                 I          Indicates that the current memory transaction          is 16-bits.116  SA06      ISA System Byte High Enable117  IRQ3      ISA I/O Channel Ready. A low adds wait                                 I          states to the current ISA bus cycle118  SD13      ISA System Data 00119  SA05      ISA active low causing current memory                                 I          cycle to be completed without additional          wait states.120  DACK2-    ISA System Data 01121  SD14      ISA System Data 02122  MASTER-   Floppy DMA 2 Request. Normally          connected to DRQ2 (pin 123)123  SA04      ISA DMA 2 Request strobe                                 I124  TC        ISA System Data 03125  SD15      ISA System Data 04126  SA03      ISA Interrupt Request 09                                 I127  BALE      ISA System Data 05128  SA02      ISA System Data 06129  SA01      ISA active high system reset signal130  OSV       ISA System Data 07131  SA00      ISA gated non-maskable interrupt input                                 I132  HISPEED   Input to select CPU speed. High=high speed.                                 I133  SPKR      Speaker output134  KDATA     Keyboard data135  KCLOCK    Keyboard clock136  PWRDN-137  GND138  COLOR     Video Color/Mono jumper                                 I139  KBLOCK    Keyboard lock. Low blocks keyboard input                                 I140  SLCT      Parallel Port141  PE        Parallel Port142  BUSY      Parallel Port143  ACK-      Parallel Port144  PD7       Parallel Port Data 7145  PD6       Parallel Port Data 6146  PD5       Parallel Port Data 5147  PD4       Parallel Port Data 4148  PD3       Parallel Port Data 3149  SLCTIN-   Parallel Port150  PD2       Parallel Port Data 2151  INIT-     Parallel Port152  PD1       Parallel Port Data 1153  ERR-      Parallel Port154  GND155  PD0       Parallel Port Data 0156  AUTOFD    Parallel Port157  STRB-     Parallel Port158  DCD2      Serial Port 2 Data Carrier Detect159  DSR2      Serial Port 2 Data Set Ready160  RXD2      Serial Port 2 Receive Data161  RTS2      Serial Port 2 Request To Send162  TXD2      Serial Port 2 Transmit Data163  CTS2      Serial Port 2 Clear To Send164  DTR2      Serial Port 2 Data Terminal Ready165  R12       Serial Port 2 Ring Indicator166  DCD1      Serial Port 1 Data Carrier Detect167  DSR1      Serial Port 1 Data Set Ready168  RXD1      Serial Port 1 Receive Data169  RTS1      Serial Port 1 Request to Send170  TXD1      Serial Port 1 Transmit Data171  CTS1      Serial Port 1 Clear to Send172  DTR1      Serial Port 1 Data Terminal Ready173  RI1       Serial Port 1 Ring Indicator174  GAMECS175  RAS3-     DRAM Row Address Strobe 3176  RAS2-     DRAM Row Address Strobe 2177  RAS1-     DRAM Row Address Strobe 1178  RAS0-     DRAM Row Address Strobe 0179  DP1       DRAM parity bit for high byte memory180  DP0       DRAM parity bit for low byte memory181  D15       DRAM Data Bit 15182  D07       DRAM Data Bit 7183  D14       DRAM Data Bit 14184  D06       DRAm Data Bit 6185  DRWE-     DRAM memory write strobe186  D13       DRAM Data Bit 13187  GND188  D05       DRAM Data Bit 5189  MA10      DRAM multiplexed memory address 10190  MA09      DRAM multiplexed memory address 9191  MA08      DRAM multiplexed memory address 8192  D12       DRAM Data Bit 12193  D04       DRAM Data Bit 4194  MA07      DRAM multiplexed memory address 7195  MA06      DRAM multiplexed memory address 6196  D11       DRAM Data Bit 11197  D03       DRAM Data Bit 3198  MA05      DRAM multiplexed memory address 5199  MA04      DRAM multiplexed memory address 4200  D10       DRAM Data Bit 10201  D01       DRAM Data Bit 2202  MA03      DRAM multiplexed memory address 3203  MA02      DRAM multiplexed memory address 2204  D09       DRAM Data Bit 9205  VCC206  D01       DRAM Data Bit 1207  MA01      DRAM multiplexed memory address 1208  MA00      DRAM multiplexed memory address 0209  D08       DRAM Data Bit 8210  D00       DRAM Data Bit 0211  CASH3-    DRAM Column Address Strobe, High byte 3212  CASL3-    DRAM Column Address Strobe, Low byte 3213  CASH2-    DRAM Column Address Strobe, High byte 2214  CASL2-    DRAM Column Address Strobe, Low byte 2215  CASH1-    DRAM Column Address Strobe, High byte 1216  CASL1-    DRAM Column Address Strobe, Low byte 1217  CASH0-    DRAM Column Address Strobe, High byte 0218  CASL0-    DRAM Column Address Strobe, Low byte 0219  BDIS220  XROMCS-221  LEDOUT-222  GND223  HDRESET-  IDE224  IDED07    IDE Data Bit 7225  HDD08     IDE Data Bit 8226  HDD06     IDE Data Bit 6227  HDD09     IDE Data Bit 9228  HDD05     IDE Data Bit 5229  HDD10     IDE Data Bit 10230  HDD04     IDE Data Bit 4231  HDD11     IDE Data Bit 11232  HDD03     IDE Data Bit 3233  HDD12     IDE Data Bit 12234  HDD02     IDE Data Bit 2235  HDD13     IDE Data Bit 13236  HDD01     IDE Data Bit 1237  HDD14     IDE Data Bit 14238  HDD00     IDE Data Bit 0239  HDD15     IDE Data Bit 15240  HDIOW-    IDE buffered I/O Write strobe______________________________________ 
    
     A second embodiment of the pin configuration for the expansion bus 24 is given in the table below with corresponding pin numbers for expansion bus connectors A, B, C, D. As mentioned before, bus 24 comprises 94 pins that includes VCC and two GND pins. 
     
         ______________________________________                            In/  Cur-Pin    Signal Name                 Function   Out  rent Load*______________________________________38   A31    IOCHCK    Address bit 0                            I/O  12   PU                                 mA39   B30    SD07      14.318 MHz clock                            Out  6 mA 33 SER40   A30    RESETDR   Address bit 1                            I/O  12   PU       V                         mA41   A29    SD06      Address bit 2                            I/O  12   PU                                 mA42   B28    SD05      Address latch enable                            Out  12                                 mA43   A28    IRQ9      Address bit 3                            I/O  12   PU                                 mA44   C18    SD04      System Data bit 15                            I/O  12   PU                                 mA45   B27    SD03      DMA Terminal                            Out  4 mA                 Count46   A27    DRQ2      Address bit 4                            I/O  12   PU                                 mA47   D17    DRQ2OUT   Bus master assert                            In   N/A  330 PU48   C17    SD02      System Data bit 14                            I/O  24   PU                                 mA49   B26    SD01-     DMA Acknowledge                            Out  4 mA                 250   A26    0WS       Address bit 5                            I/O  12   PU                                 mA51   C16    SD00      System Data bit 13                            I/O  24   PU                                 mA52   B25    IOCHRDY   Interrupt Request 3                            In   N/A  PU53   A25    SBHE-     Address bit 6                            I/O  12   PU                                 mA54   D15    MEMCS 16- DMA Request 7                            In   N/A  PD55   C15    AEN       System Data bit 12                            I/O  24   PU                                 mA56   B24    SMEMW-    Interrupt Request 4                            In   N/A  PU57   A24    LA23      Address bit 7                            I/O  12   PU                                 mA58   D14    IOCS16-   DMA Acknowledge                            Out  4 mA                 759   C14    SA19      System Data bit 11                            I/O  24   PU                                 mA60   B23    SMEMR-    Interrupt Request 5                            In   N/A  PU61   A23    LA22      Address bit 8                            I/O  12   PU                                 mA62   D13    IRQ10     DMA Request 6                            In   N/A  PD63   C13    SA18      System Data bit 10                            I/O  24   PU                                 mA64          IOW-      Floppy Disk                 Interrupt Request65   B22    LA21      Interrupt Request 6                            In   N/A  PU66   A22    IRQ11     Address bit 9                            I/O  12   PU                                 mA67          GND68   D12    SA17      DMA Acknowledge                            Out  4 mA                 669   C12    IOR-      System Data bit 9                            I/O  24   PU                                 mA70          LA20      Parallel Port                 Interrupt Request71   B21    IRQ12     Interrupt Request 7                            In   N/A  PU72   A21    SA16      Address bit 10                            I/O  12   PU                                 mA73   D11    DACK3-    DMA Request 5                            In   N/A  PD74   C11    LA19      System Data bit 8                            I/O  24   PU                                 mA75   B20    IRQ15     System clock (8                            Out  12                 MHz)            mA76   A20    SA15      Address bit 11                            I/O  12   PU                                 mA77   D10    DRQ3      DMA Acknowledge                            Out  4 mA                 578   C10    LA18      Memory Write                            I/O  6 mA PU, 33                                      SER79   B19    IRQ14     Memory Refresh                            I/O  6 mA 470 PU,                                      33 SER80   A19    SA14      Address bit 12                            I/O  12   PU                                 mA81   D9     DACK1-    DMA Request 0                            In   N/A  PD82   C9     LA17      Memory Read                            I/O  6 mA PU, 33                                      SER83   B18    DACK0-    DMA Request 1                            In   N/A  PD84   A18    SA13      Address bit 13                            I/O  12   PU85          VCC                       mA86   D8     DRQ1-     DMA Acknowledge                            Out  4 mA                 087   C8     MEMR-     Address bit 17                            I/O  24                                 mA88   B17    DRQ0      DMA Acknowledge                            Out  4 mA                 189   A17    SA12      Address bit 14                            I/O  12   PU                                 mA90   D7     REFRESH-  Interrupt Request 14                            In   N/A  PU91   C7     MEMW-     Address bit 18                            I/O  24                                 mA92   B16    DACK5-    DMA Request 3                            In   N/A  PD93   A16    SA11      Address bit 15                            I/O  12   PU                                 mA94   D6     SYSCLK    Interrupt Request 15                            In   N/A  PU95   C6     SD08      Address bit 19                            I/O  24                                 mA96   B15    DRQ5      DMA Acknowledge                            Out  4 mA                 397   A15    SA10      Address bit 16                            I/O  12   PU                                 mA98   D5     IRQ7      Interrupt Request 12                            In   N/A  PU99   C5     IRQ7OUT   Address bit 20                            I/O  24                                 mA100  B14    SD09      I/O Read   I/O  6 mA PU101  A14    DACK6-    Address bit 17                            I/O  12   PU102         GND                       mA103  D4     SA09      Interrupt Request 11                            In   N/A  PU104  C4     IRQ6      Address bit 21                            I/O  24                                 mA105  B13    IRQ6OUT   I/O Write  I/O  6 mA PU106  A13    SD10      Address bit 18                            I/O  12   PU                                 mA107  D3     DRQ6      Interrupt Request 10                            In   N/A  PU108  C3     SA08      Address bit 22                            I/O  24                                 mA109  B12    IRQ5      Mem Read (lower                            I/O  6 mA 33 SER                 IMB)110  A12    SD11      Address bit 19                            I/O  12   PU                                 mA111  D2     DACK7-    16-bit I/O access                            In   N/A  330 PU112  C2     SA07      Address bit 23                            I/O  24                                 mA113  B11    IRQ4      Mem Write (lower 1                            I/O  6 mA 33 SER                 MB)114  A11    SD12      Address Enable                            I/O  12   PU                                 mA115  D1     DRQ7      16-bit mem access                            In   N/A  330 PU116  C1     SA06      Bus High Enable                            I/O  12   PU                                 mA117  A10    IRQ3      Processor Ready                            In   N/A  1K PU                 Ctrl118  A9     SD13      System Data bit 0                            I/O  24   PU                                 mA119  B8     SA05      Zero wait state                            In   N/A  330 PU120  A8     DACK2-    System Data bit 1                            I/O  24   PU                                 mA121  A7     SD14      System Data bit 2                            I/O  24   PU                                 mA122         MASTER-   Floppy DMA 2                 Request123  B6     SA04      DMA request 2                            In   N/A  PD124  A6     TC        System Data bit 3                            I/O  24   PU                                 mA125  A5     SD15      System Data bit 4                            I/O  24   PU                                 mA126  B4     SA03      Interrupt request 9                            In   N/A  PU127  A4     BALE      System Data bit 5                            I/O  24   PU                                 mA128  A4     SA02      System Data bit 6                            I/O  24   PU                                 mA129  B2     SA01      System reset signal                            Out  24                                 mA130  A2     OSC       System Data bit 7                            I/O  24   PU                                 mA131  A1     SA00      Sub NMI input                            In   N/A  4.7K                                      PU______________________________________ 
    
     The exact pin configuration as illustrated for the expansion bus on FIG. 5 is a critical feature of the invention. Since it forms a single row of pins on the module 10, the pins can be easily connected directly to the expansion bus connectors without having to resort to multiple layer boards to route the PC board tracks from the module 10 to the expansion bus connectors A, B, C, D. Furthermore, as mentioned above, the present invention includes both microprocessor modules as illustrated in FIG. 3, as well as peripheral controller modules such as display controller modules, Ethernet control modules, and PCMCIA compatible modules for extended memory (RAM, ROM, EEPROM, flash memory, etc.), as well as for modem, fax, and network interfaces, and also for wireless communication devices. By providing an identical pin configuration for the ISA buses, the various modules can easily be connected to one another. 
     A further feature of the invention is illustrated in FIG. 6. FIG. 6 illustrates a card 54 having a mounting site 56 for a module having a pin configuration as described above with reference to FIG. 4. The card 54 provides an integrated way for system development in standard ISA passive backplane systems. The card includes an AT-bus and a PC/104 bus, and occupies a single slot in an AT-class (16-bit) passive backplane. This allows development to be performed using a terminal on a serial port as a console. A standard VGA or SVGA display controller can be plugged into another slot on the backplane if desired. Instead, a PC/104 display controller can be installed directly on the PC/104 header 58 on the card 54. Since the module 10 is fully compatible with PC/AT ISA, a wide selection of hardware peripherals may be integrated. The ISA-compatible bus allows an OEM to easily interface his proprietary hardware design with the module 10. Furthermore, the standard BIOS and embedded DOS allows application software to be developed using standard desk top PCs and standard development tools for implementation on the system using one or more modules of the present invention. It will be appreciated that, depending on the nature of the module, the size of the module and the number of pins may vary, however it is an important feature of this invention that the pins for the ISA bus retain their configuration in each module to allow the modules to be readily connected to one another as illustrated in FIG. 7 in which different modules 60, 62, 64 of the invention are connected to each other by means of bus lines 66, 68 extending between the ISA compatible bus pins indicated by reference numerals 70, 72, 74, respectively.