Abstract:
An integrated circuit device may include a first integrated circuit (IC) portion having a memory array that stores data units as storage locations and burst access circuitry that sequentially accesses N relates storage locations within the memory array, where N&gt;1; and a second IC portion comprising a plurality of burst access registers coupled to the burst access circuitry, each burst access register having register locations to store at least N data units, and being coupled to a corresponding port by a single data unit access path.

Description:
This application claims the benefit of U.S. provisional patent application Ser. No. 61/167,971 filed on Apr. 9, 2009, the contents of which are incorporated by reference herein. This application is also a continuation-in-part of U.S. patent application Ser. No. 12/720,517 filed on Mar. 9, 2010 which claims the benefit of U.S. provisional patent application Ser. No. 61/158,676 filed on Mar. 9, 2009. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to integrated circuit devices, and more particularly to memory devices having multiple ports to access storage locations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block schematic diagram of a memory device according to a first embodiment. 
         FIGS. 2A and 2B  are block schematic diagrams of memory devices according to other embodiments. 
         FIGS. 3A to 3C-1  are a sequence of block schematic diagrams showing memory devices and methods according to further embodiments. 
         FIGS. 4A and 4B  are block schematic diagrams showing a memory device and method according to yet other embodiments. 
         FIGS. 5A and 5B  are block schematic diagrams showing a memory device and method according to other embodiments. 
         FIGS. 6A to 6D  are a series of top plan views showing memory devices and methods according to embodiments. 
         FIGS. 7A to 7D  are a sequence of side cross sectional views showing a memory device and method according to yet another embodiment. 
         FIG. 8  is a block schematic diagram of a memory device according to an embodiment. 
         FIG. 9  is a block schematic diagram of a memory device according to a further embodiment. 
         FIG. 10  is a block schematic diagram of a memory device according to yet another embodiment. 
         FIGS. 11A and 11B  are block schematic diagrams of memory devices according to additional embodiments. 
         FIGS. 12A to 12C  are block schematic diagrams of memory devices according to other embodiments. 
         FIG. 13  is a flow diagram of a method according to an embodiment. 
         FIG. 14  is a flow diagram of a method according to a further embodiment. 
         FIG. 15  is a flow diagram of a method according to yet another embodiment. 
         FIG. 16  is a flow diagram of a method according to an embodiment. 
         FIG. 17  is a flow diagram of a method according to an embodiment. 
         FIG. 18  is a block schematic diagram of a memory device according to another embodiment. 
         FIG. 19  is a timing diagram showing multi-port memory accesses according to one particular embodiment. 
         FIG. 20  is a timing diagram showing multi-port memory accesses according to another particular embodiment. 
         FIG. 21  is a block schematic diagram of a memory device according to a further embodiment. 
         FIG. 22  is a block diagram of a first-in-first-out (FIFO) memory device according to an embodiment. 
         FIGS. 23A to 23H  are a sequence of block diagrams showing FIFO device write operations according to an embodiment. 
         FIGS. 24A to 23C  are a sequence of block diagrams showing FIFO device read operations according to an embodiment. 
         FIGS. 25A to 25E  are a sequence of block diagrams showing FIFO device “fall through” operation according to an embodiment. 
         FIGS. 26A to 26D  are a sequence of block diagrams showing FIFO device “fall through” operations according to another embodiment. 
         FIG. 27  is a block diagram of a multi-port memory device according to an embodiment. 
         FIG. 28  is a block schematic diagram showing modify operations that may be performed in an embodiment like that of  FIG. 27 . 
         FIGS. 29A to 29D  are a sequence of block diagrams showing multi-port memory device write operations according to an embodiment. 
         FIGS. 30A to 30D  are a sequence of block diagrams showing multi-port memory device read operations according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments will now be described that show multi-port memory devices and methods that include a single port memory integrated circuit portion connected to two or more memory ports by another integrated circuit portion. In the various embodiments shown herein, like sections may be referred to by the same reference characters, but with the leading digit(s) corresponding to the figure number. 
     Referring now to  FIG. 1 , an integrated circuit device according to a first embodiment is shown in a block schematic diagram and designated by the general reference character  100 . A device  100  may include a single port memory (SPM) portion  102  and a port expansion portion  104  connected to one another over a single port connection  106 . 
     An SPM portion  102  may include one or more SPM memory arrays accessed by one memory port. A memory port may include those signals necessary to access memory device for read and/or write operations. In one embodiment, a memory port may generally include control inputs (C) for determining a type, timing and location of an access operation (e.g., read or write, program or erase) and one or more data paths (D) for enabling data to be read from and/or written to the memory array(s). In a very particular embodiment, a control inputs may include command data signals, address signals, and timing (e.g., clock) signals. 
     An SPM memory portion  102  may differ from “true” dual port arrays in that arrays may not be accessed simultaneously by way of two different ports, but rather may be accessed sequentially by a single port. Consequently, an SPM memory portion  102  may be less complex than, occupy less area than, and be less costly to manufacture than a true dual-port memory circuit. 
     In some embodiments, an SPM memory portion  102  may include memory arrays based all or in part on any of various memory technologies, including but not limited to: dynamic random access memories (DRAMs), static RAMs (SRAMs), “pseudo” SRAMs (e.g., memories with DRAM based cores and SRAM type interfaces), or electrically erasable and programmable read-only-memories (EEPROMs), such and NAND type flash memories and/or NOR type memories. 
     Single port connection  106  may be a parallel port connection, or alternatively, a serial port connection. 
     A port expansion portion  104  may include two or more memory ports  108 - 0  to -n. Each memory port ( 108 - 0  to -n) may serve as a data access “pipe” for another device to access storage locations within SPM portion  102  of memory device. As such, each port ( 108 - 0  to -n) may receive signals for accessing memory locations within SPM portion  102  by way of single port connection  106 , and may also output data from SPM portion  102  to any of ports ( 108 - 0  to -n). A port expansion portion  104  may include multi-port access logic that may transform or forward requests at any of various ports ( 108 - 0  to -n) into ordered accesses to SPM portion  102 . 
     In particular embodiments, such multi-port access may be random access logic that allows requests from various ports to be serviced in a random order. 
     In other embodiments, a port expansion portion  104  may include first-in-first-out (FIFO) logic that may process accesses from multiple ports in first-in-first-out fashion (with respect to port inputs). In such embodiments, requests from multiple ports may be ordered within a port expansion portion and applied in a sequential order to SPM portion  102 . In a similar fashion, data may be output from SPM portion  102  in a sequential fashion and then forwarded to an appropriate port ( 108 - 0  to -n). 
     As will be described in more detail below, in some embodiments, all or a portion of a port expansion portion  104  may be formed with programmable circuits that are programmed with configuration values to provide communication paths between ports ( 108 - 0  to -n) and a single port of SPM portion  102 . Further, in some embodiments, all or a portion of a port expansion portion  104  may be formed in a same substrate as SPM portion  102 . Alternatively, SPM portion  102  and port expansion portion  104  may be separate integrated circuit devices connected to one another in a single integrated circuit package. 
     In this way, an integrated circuit device may include a first IC portion having an SPM and a second IC portion that enables any of multiple ports to access the SPM. 
     Referring to  FIGS. 2A and 2B , very particular embodiments of a dual-port memory device (DPM) are shown in block schematic diagrams. The embodiments of  FIGS. 2A and 2B  may be very particular implementations of that shown in  FIG. 1 . 
     Referring to  FIG. 2A , a DPM device is shown in a block schematic diagram and designated by the general reference character  200 . A DPM  200  may include a single port connection  206  having a data path (D) divided into a read data path (R) that may output data from an SPM portion  202 , as well as a write data path (W) that may receive data from a port expansion portion  204 . 
     In addition, a port expansion portion  204  may include a first parallel port (PORT 0 )  210 - 0  and a second parallel port (PORT 1 )  210 - 1  that may be connected to single port connection  206  by FIFO logic. Parallel ports ( 210 - 0 / 1 ) may provide control and data paths where multi-bit data values are transmitted in parallel. For example, in a read operation multi-bit address and command data may be received in parallel (in one or more sets), on input on signal lines. Subsequently, read data may be output in parallel on signal lines. In a write operation, multi-bit address, command data, and write data may be received in parallel (in one or more sets) on input on signal lines. In particular embodiments, address and data values may be multiplexed, with address values being applied at a different time than corresponding data values. 
     It is understood that parallel ports (PORT 0  and PORT 1 ) may be different types of parallel ports. Different parallel ports may include, without limitation, DRAM type interfaces (e.g., DDR, DDR2, DDR3), SRAM interfaces, or flash memory interfaces. Referring to  FIG. 2B , another DPM device is shown in a block schematic diagram and designated by the general reference character  200 ′. A DPM device  200 ′ may include sections like those of  FIG. 2A , however, unlike  FIG. 2A , a port expansion portion  204 ′ may include a first serial port (PORT 0 )  212 - 0  and a second serial port (PORT 1 )  212 - 1  which may be connected to single port connection  206  by FIFO logic. Serial ports ( 212 - 0 / 1 ) may provide control and data paths where multi-bit data values are transmitted in a serial manner. For example, in a read operation either of a multi-bit address and command data value may be received in a serial fashion on one or more signal lines. Subsequently, read data may be output in serial fashion on one or more signal lines. In a like fashion, in a write operation, multi-bit address, command data, and write data may be received in a serial fashion on one or more input signal lines. 
     As in the case of  FIG. 2A , in  FIG. 2B  serial ports (PORT 0  and PORT 1 ) may be different types of serial ports. Different serial ports may include, without limitation, PCI Express, RapidlO, USB, Serial ATA (SATA) or IEEE 1394 interface (Firewire). 
     Parallel ports ( 210 - 0 / 1 ) and/or serial ports ( 212 - 0 / 1 ) may have input write data lines separate from output read data lines, or may include data input/output (I/O) lines for both read and write data. 
     While  FIG. 2A  shows only parallel ports and  FIG. 2B  shows only serial ports, other embodiments may include one or more parallel ports in conjunction with one or more serial ports. 
     In this way, a SPM memory may be accessed by any of multiple parallel ports and/or serial ports. 
     Referring now to  FIGS. 3A to 3C-1 , programmable multi-port memory devices and methods according to other embodiments are shown in a series of block schematic diagrams. 
     Referring to  FIG. 3A , a memory device is shown in a block schematic diagram and designated by the general reference character  300 . A device  300  may include an SPM portion  302  and a programmable circuit portion  314 . An SPM portion  302  may have features of SPM portions described in other embodiments herein, and equivalents. 
     A programmable circuit portion  314  may include programmable circuits that may be configured into various functions based on configuration data. In some embodiments, a programmable circuit portion  314  may include circuits that are capable of being reconfigured many times. Such circuits may include volatile storage circuits that are loaded with configuration data (from a nonvolatile memory) for example, to thereby be programmed to a particular configuration. Alternatively, programmable circuit portion  314  may include one-time programmable elements (e.g., anti-fuse) for establishing a desired function. Still further, as a will be shown in other embodiments below, programmable circuit portion  314  may include one or more non-programmable circuit blocks with set functions in addition to programmable circuits. In some embodiments, all or a portion of a programmable circuit portion  314  may be formed in a same substrate as SPM portion  302 . Alternatively, SPM portion  302  and programmable circuit portion  314  may be separate integrated circuit devices connected to one another in a single integrated circuit package. 
     Referring still to  FIG. 3A , in the embodiment shown, a programmable circuit portion  314  may include a number of programmable input/output (I/O) lines  316 - 0  to  316 - 2 . Programmable I/O lines  316 - 0  may be connected to SPM portion  302  (and after a programming step may form a single port connection  306 ). 
     Referring now to  FIG. 3B , a programmable circuit portion  314  may receive configuration data (CFG. DATA). Such configuration data may establish a function of programmable circuits within portion  314 . 
       FIG. 3C-0  shows a first programmed embodiment of device  300  after a programmable circuit portion  314  has been configured in response to one set of configuration data. As shown in the figure, programmable circuit portion  314  may be configured to include a first parallel interface (I/F)  318 - 0 , a second parallel interface (I/F)  318 - 1 , and FIFO logic  320 . With parallel interfaces  318 - 0 / 1  created, programmable I/Os  316 - 1  form part of a first parallel port PORT 0  while programmable I/Os  316 - 2  form part of a second parallel port. In addition, FIFO logic  320  may result in programmable I/Os  316 - 1  forming a single port connection  306 . The programmed device of  FIG. 3C-0  may be one version of that shown in  FIGS. 1 and/or 2A . 
       FIG. 3C-1  shows a second programmed embodiment of device  300  after a programmable circuit portion  314  has been configured in an alternative way in response to another set of configuration data. As shown in the figure, programmable circuit portion  314  may be configured to include a first serial I/F  322 - 0 , a second serial I/F  322 - 1 , and FIFO logic  320 . Consequently, programmable I/Os  316 - 0 , - 1 , and - 2  may form parts of a single port connection  306 , first serial port PORT 0   312 - 0 , and second serial port  312 - 1 , respectively. The programmed device of  FIG. 3C-1  may be one version of that shown in  FIGS. 1 and/or 2B . 
     While the embodiments of  FIGS. 3C-0 and 3C-1  show programmable circuit portion  314  configured to include two ports to access SPM portion  302 , other embodiments may include more ports for accessing a same single port section. Further, while  FIGS. 3C-0 and 3C-1  show FIFO logic  320  other embodiments may have different kind of logic for forwarding requests to SPM portion  302 . 
     In this way, a multi-port memory device may include programmable circuits that may be programmed to form two or more ports for accessing a single port device. Such programmability may enable one device to be deployed that can accommodate multiple different port specifications by allowing the device to be programmed to meet such specifications. Thus, a programmable circuit portion to provide a flexible interface to accommodate various applications. 
     While the embodiments of  FIGS. 3A to 3C-1  show a programmable circuit portion in which various sections of a port expansion section are created with programmable circuits, in other embodiments, a programmable circuit portion may include circuit blocks with predetermined functions that are substantially not programmable. Such embodiments will be described with reference to  FIGS. 4A to 5B . 
     Referring to  FIG. 4A , a memory device is shown in a block schematic diagram and designated by the general reference character  400 . A device  400  may include an SPM portion  402  and a programmable circuit portion  414 , like the embodiment shown in  FIG. 3A . However, unlike  FIG. 3A , programmable circuit portion  414  may include a prefabricated section  424 , which in this case is a memory I/F that may communicate with SPM portion  402  along single port connection  406 . That is, programmable portion  414  is manufactured with a memory interface  424 , thus such all or a portion of such a feature does not necessarily have to be created with programmable circuits. 
       FIG. 4B  shows device  400  after a programmable circuit portion  414  has been configured in response to configuration data. As shown in the figure, programmable circuit portion  414  has been configured to include a first I/F  426 - 0 , a second I/F  426 - 1 , and FIFO logic  420 . Interfaces  426 - 0 / 1  may be parallel or serial interfaces that form memory ports  408 - 0 / 1 . The programmed device of  FIG. 4B  may be one version of that shown in any of  FIGS. 1 to 2B . 
     Referring to  FIG. 5A , a memory device is shown in a block schematic diagram and designated by the general reference character  500 . A device  500  may include an SPM portion  502  and a programmable circuit portion  514 . Programmable circuit portion  514  may also include prefabricated sections  526 - 0  and - 1 , which in this case may be interfaces (I/F) that provide ports ( 508 - 0 / 1 ) for accessing SPM portion  502 . Interfaces (I/F) may be parallel or serial interfaces. 
       FIG. 5B  shows device  500  after a programmable circuit portion  514  has been configured in response to configuration data. As shown in the figure, programmable circuit portion  514  has been programmed to include FIFO logic  520  that may allow access to SPM portion  502  by way of ports  508 - 0 / 1 . 
     In this way, a multi-port memory device may include programmable circuits that may be programmed to form two or more ports for accessing a single port device, where such programmable circuits may include sections with prefabricated circuits that are not substantially programmable. The programmed device of  FIG. 5B  may be one version of any of those shown in  FIGS. 1 to 2B . 
     A memory device according to embodiments may include an SPM portion and a port expansion portion, which may be programmable, partially programmable or substantially not programmable. In some embodiments, such different portions may be formed in a same integrated circuit substrate, as shown in  FIGS. 6A to 6D . 
     Referring to  FIG. 6A , memory devices  600 -A to -I may be formed in a manufacturing substrate  628  (memory devices  600 -B to -I only shown in part). Each memory device ( 600 -A to -I) may include an SPM portion  602  and a programmable circuit portion  614  such as those described in the embodiments herein, or equivalents. Accordingly, an SPM portion  602  may be conceptualized as being embedded with a programmable circuit  614 , or vice versa. 
     In one embodiment, a substrate  628  may be a semiconductor substrate. In a particular embodiment, a substrate may be a semiconductor wafer and portions  602  and  614  may be fabricated with integrated circuit manufacturing techniques. 
     Referring to  FIG. 6B , a manufacturing substrate  628  may be divided into individual device substrates (one shown as  630 ). In one embodiment, a wafer may be cut into individual dice (e.g.,  630 ). Thus, each die has integrated on it both an SPM portion  602  and a programmable circuit portion  614 . 
     Referring to  FIG. 6C , design data (HDL)  632  may be created for a particular port configuration that is compatible with programmable circuit portion  614 . Such design data  632  may be converted to configuration data (CFG) suitable for programmable circuit portion  614  by a data converter  634 . As a result, programmable circuit portion  614  may be programmed to provide multiple ports for accessing SPM portion  602 . In very particular embodiments, a programmable circuit portion  614  may be programmed as shown in  3 A to  3 B. 
     While devices may be fabricated with a programmable portion that is configured with design data to provide multiple ports to a single port memory architecture, the same design data may be utilized to fabricate a substantially non-programmable port expansion portion. Such an embodiment is shown in  FIG. 6D . 
     Referring to  FIG. 6D , design data (HDL)  632 ′ may be created for a particular port configuration that is compatible with programmable circuit portion  614 . Such design data  632 ′ may be converted into a physical design by a design tool  636 . Physical design data may include the physical circuit layout (e.g., mask layers) for creating a port expansion portion. Such a physical design may create a port expansion portion  604  with SPM portion  602  to create a substantially non-programmable multi-port device. In particular embodiments, a port expansion portion  604  may be a logic “sliver” (e.g., relatively small portion of a semiconductor substrate) that may be added to an existing SPM portion  602  design. 
     Referring to  FIGS. 6C and 6D , in some embodiments, design data  632 ′ may be the same as that shown as  632  in  FIG. 6C . For example, while an initial manufacturing of a memory product may occur as shown in  FIG. 6C , if demand reaches a predetermined level, a device having the same functionality may be created as shown in  FIG. 6D . In such an embodiment, a port expansion portion formed with the physical design may be substantially smaller than a programmable circuit portion  614 . 
     In very particular embodiments, a device like that of  FIG. 6C  may be one version of any of those shown in  FIGS. 1 to 5B . Further, a device like that of  FIG. 6D  may be one version of that shown in any of  FIG. 1, 2A or 2B . 
     In this way, a memory device may have a single port memory portion and a port expansion portion formed in a same substrate. 
     While the embodiments of  FIGS. 6A to 6D  show a memory device in which an SPM portion and a port expansion portion may be formed in a same integrated circuit (IC) substrate, other embodiments may include such portions being formed in different IC substrates. One such embodiment is shown in  FIGS. 7A to 7D . 
     Referring to  FIG. 7A , a memory device  700  may include a multi-die IC package structure  738 . A package structure  738  may provide conductive connections between multiple IC devices (e.g., dice) as well as other circuit elements such as passive circuit elements. In addition, a package structure  738  may also provide input and output connections for communicating with other devices of a larger system. In the embodiment shown, a package structure  738  may be multi-chip circuit board structure that allows connections to IC dice on one side, and package connections on another. However, other embodiments may include other device orientations, such as vertical dice stacking, including dice connected by vertical through vias and/or aligned pad locations. 
     Referring to  FIG. 7B , a first IC substrate may be connected to package structure  738 . In the embodiment shown, such a first IC substrate may be an SPM portion  702 . An SPM portion  702  may have a structure like that described in other embodiments, and equivalents. 
     Referring to  FIG. 7C , a second IC substrate may be connected to package structure  738 . In the embodiment shown, such a second IC substrate may be a port expansion portion  704 . In some embodiments, such a port expansion portion may be a programmable circuit portion  714  that is programmed to provide multi-port access to SPM portion  702 , or may be programmed (or reprogrammed) at a later point to provide such function. 
     Referring to  FIG. 7D , a protection structure  740  may be formed over SPM portion  702  and port expansion portion  704 . Further external package connections (one shown as  742 ) may be finalized to form a memory device  700 . A memory device  700  may thus form a “system-in-package” (SIP) that includes SPM portion and port expansion portion (or programmable circuits to form a port expansion portion). 
     In particular embodiments, a memory device  700  may be one implementation of those shown in any of  FIGS. 1 to 5B . 
     In this way, a memory device may have a single port memory portion and a port expansion portion formed in different substrates and assembled into a same integrated circuit package. 
     Referring to  FIG. 8 , a very particular embodiment of a memory device is shown in a block schematic diagram and designated by the general reference character  800 . A memory device  800  may include a DPM portion  802  and a port expansion portion  804 . A memory device  800  may include single port memory (SPM) arrays  844 , a write data register  846 , a write address decoder  848 , a read data register  850 , a read address decoder  852 , and a timing and control circuit  854 . SPM arrays  844  may include storage locations to store data received in write operations, and output stored data in read operations. SPM arrays  844  may be accessible for read and write operations in a sequential fashion. In particular embodiments, SPM arrays  844  may be volatile memory arrays, even more particularly, static random access memory (SRAM) arrays. 
     A write data register  846  may store write data received on a write data bus (W) that is to be stored within one of single port memory arrays  844 . A write address decoder  848  may receive a write address on address lines (ADD), and decode such an address to determine where write data is to be stored within SPM arrays  844 . Similarly, a read address decoder  852  may receive a read address on address lines (ADD), and decode such an address to determine from where read data is to be output. Read data register  850  may store read data output from SPM arrays  844 , and provide such data on read data bus (R). 
     A timing and control circuit  854  may receive command data (CMD) indicating a type of operation (e.g., read or write) as well as timing signals (K) for controlling the timing of operations executed by SPM portion  802 . 
     In one particular embodiment, an SPM portion  802  may have an architecture of a QDR™ Synchronous SRAM like those manufactured by Cypress Semiconductor Corporation having offices in San Jose, Calif., U.S.A. In a very particular embodiment, an SPM portion  802  may be a QDR™ Synchronous SRAM in die form. 
     In the embodiment of  FIG. 8 , a SPM portion  802  may be connected to a port expansion portion  804  by a single port connection  806  that includes a write data input (W), a read data output (R), and a control input (C) that may include timing signals (K), command data (CMD), and address values (ADD). 
     Referring still to  FIG. 8 , a port expansion portion  804  may include a first I/F circuit  826 - 0 , a second I/F circuit  826 - 1 , a FIFO input path  856 , a port control circuit  858 , an output multiplexer (MUX) circuit  860 , and optionally, an output translation circuit  862 . First and second I/F circuits  826 - 0 / 1  may be parallel and/or serial interfaces according to embodiments described herein, and equivalents. Such I/F circuits  826 - 0 / 1  may provide separate ports  808 - 0 / 1  for accessing SPM portion  802 . 
     FIFO input path  856  may be connected to first and second I/F circuits  826 - 0 / 1 , and receive port access requests from such I/F circuits. Such access requests may include control data (e.g., address data, command data, and optionally timing signals) and input write data. A FIFO input path  856  may order such requests in a first-in-first-out fashion, to provide a sequence of requests to SPM portion  802  (through port control circuit  858 ). Accordingly, in particular embodiments, if two requests are received substantially simultaneously, FIFO input path  856  will order such requests in a sequential fashion according to predetermined criteria. Further, FIFO input path  856  may receive and/or determine port origination information for a port control circuit that indicates from which port (e.g.,  808 - 0  or - 1 ) a request (in particular a read request) originates. 
     A port control circuit  858  may receive sequences of requests from FIFO input path  856 , and generate memory control signals suitable to SPM portion  802  to execute such requests. In addition, a port control circuit  858  may provide port select signals PSEL to FIFO output path  860  based on port origin information. Such an arrangement may ensure output data (e.g., read data) is output to the port originating the corresponding read request. In some embodiments, a port control circuit  858  may include command translation circuits in the event signals received at a port (e.g.,  808 - 0 / 1 ) are not compatible with an architecture of SPM portion  802 . In particular embodiments, a port control circuit  858  may be a circuit created with programmable circuits, thus a device  800  may accommodate various memory request formats. 
     Output MUX circuit  860  may have outputs connected to first and second I/F circuits  826 - 0 / 1  and receive output data from SPM portion  802 . Based on port selection information (PSEL), output MUX circuit  860  may output data to a designated port (e.g.,  808 - 0  or - 1 ). 
     Optional output translation circuit  862  may receive data output from SPM portion  802  and translate it into a different format in the event devices at the ports  808 - 0 / 1  expect a different data format than that provided by SPM portion  802 . As in the case of port control circuit  858 , in particular embodiments, an output translation circuit  862  may be a circuit created with programmable circuits, thus a device  800  may accommodate various data format types. 
     In very particular embodiments, a memory device  800  may be one version of any of those shown in  FIGS. 1 to 7D . 
     In this way, a memory device may include an SPM portion having separate read and write data buses, as well as separate read and write address decoders that receive address values from a same address bus. 
     Referring to  FIG. 9 , another very particular embodiment of a memory device is shown in a block schematic diagram and designated by the general reference character  900 . A memory device  900  may include a SPM portion  902  and a programmable circuit portion  914 . An SPM portion  902  may take the form of SPM portions shown in other embodiments herein, and equivalents. 
     A programmable circuit portion  914  may have programmable I/Os  916 - 0  that are connected or connectable to SPM portion  902 , as well as programmable I/Os  916 - 1 / 2  that may serve as port I/Os in a programmed device. All or a portion of programmable circuit portion  914  may have a field programmable gate array (FPGA) type architecture, including a number of programmable sectors  964 . 
     A programmable sector  964  for inclusion in the embodiments is shown in circle in  FIG. 9 . In the embodiment shown, programmable sector  964  may include a programmable core  966 , programmable input MUXs  968 - 0 / 1 , programmable output de-MUXs  970 - 0 / 1 , data lanes  972 - 0  to - 3 , and programmable switch sections  974 - 0  to - 3 . A programmable core  966  may provide selectable logic functions according to configuration data, and may include programmable logic circuits, as but one example. 
     Data lanes  972 - 0  to - 3  may include multiple signal lines, and collectively, may interconnect multiple programmable sectors  964  with one another. Programmable input MUXs  968 - 0 / 1  may selectively connect signals lines from data lanes  972 - 1 / 3  to inputs of programmable core  966  based on configuration data. Similarly, programmable output de-MUXs  970 - 0 / 1  may selectively connect outputs from programmable core  966  to signals lines of data lanes  972 - 1 / 3  based on configuration data. Switch sections  974 - 0  to - 3  may selective connect signals of data lines to one another based on configuration information. An FPGA like architecture may enable the creation of re-configurable port expansion circuits having high data throughput rates, while allowing for flexibility in designs. 
     In very particular embodiments, a memory device  900  may be one version of any of those shown in  FIGS. 1 to 6C and 7A to 8 . 
     In this way, a memory device may include an SPM portion and a programmable circuit portion with an FPGA type architecture that may be programmed into a port expansion portion. 
     While some embodiments shown herein may include port expansion portions that allow two ports to access an SPM portion, other embodiments may include more than two ports. One particular embodiment having more than two ports is shown in  FIG. 10 . 
     Referring to  FIG. 10 , an embodiment of a memory device is shown in a block schematic diagram and designated by the general reference character  1000 . A memory device  1000  may include a SPM portion  1002  and a port expansion portion  1004 . An SPM portion  902  may take the form of SPM portions shown in other embodiments herein, and equivalents. 
     A port expansion portion  1004  may include multiple FIFO logic sections to order requests from more than two ports. In the embodiment shown, port expansion portion  1004  may include three FIFO logic sections  1020 - 0  to - 2  to enable requests to be sequentially ordered from four ports (PORT 0  to PORT 3 )  1008 - 0  to - 3  prior to being applied to SPM portion  1002 . In more detail, a FIFO logic section  1020 - 0  may sequence requests from ports  1008 - 0 / 1  (PORT 0  and PORT 1 ). FIFO logic section  1020 - 1  may sequence requests from ports  1008 - 2 / 3  (PORT 2  and PORT 3 ). FIFO logic section  1020 - 2  may sequence requests output from the other FIFO logic sections  1020 - 0 / 1 . Memory device of  FIG. 10  may be one particular implementation of that shown in  FIG. 1 . 
     In this way, a memory device may include a port expansion portion with more than two ports that order requests form such ports with FIFO logic sections. 
     While embodiments of the invention may include circuits for enabling multi-port communication with an SPM portion, other embodiments may additionally include processing of data stored by an SPM portion. Two such embodiments will now be described with reference to  FIGS. 11A and 11B . 
     Referring now to  FIGS. 11A and 11B , memory devices according to further embodiments are shown in block schematic diagrams and designated by the general reference characters  1100  and  1100 ′, respectively. Memory device  1100  and  1100 ′ may each include an SPM portion  1102  and a port expansion portion  1104 . An SPM portion  1102  may take the form of SPM portions shown in other embodiments herein, and equivalents. 
     Port expansion portions  1104  and  1104 ′ may include I/F circuits  1126 - 0 / 1  and access logic  1120 . Such items may take the form of those shown in other embodiments, or equivalents. However, port expansion portions  1104  and  1104 ′ may also include data processing sections  1178  and  1178 ′. 
     Referring to  FIG. 11A , a data processing section  1178  of memory device  1100  may include an encryption circuit  1180 - 0  and a decryption circuit  1180 - 1 . An encryption circuit  1180 - 0  may encrypt write data prior to such data being written into SPM portion  1102 . A decryption circuit  1180 - 1  may decrypt read data prior to such data being output from SPM portion  1102 . 
     In a particular embodiment, data processing section  1178  may be formed with programmable circuits, thus enabling different encryption/decryption schemes to be implemented according to application. 
     Referring to  FIG. 11B , a data processing section  1178 ′ of memory device  1100 ′ may include error correction circuits. In particular, an error code generation circuit  1182 - 1  may generate error correction codes (ECC) from received write data, and allow such codes to be stored with corresponding write data within SPM portion  1102 . In addition, a error check and correction circuit  1182 - 0  may receive read data values and corresponding ECC values from SPM portion, and check (and correct, if necessary) read data values prior to such data values being output from a port (e.g.,  1108 - 0  or - 1 ). 
     It is noted that the error correction configuration like that shown in  FIG. 11B  may also be implemented in the opposite data direction. That is, write data with corresponding ECC values may arrive from a port (e.g.,  1108 - 0  or - 1 ). An error check and correction circuit may receive such write data values and corresponding ECC values and check (and correct, if necessary) the write data prior to such data values being written into an SPM portion. In addition, an error code generation circuit may generate error correction codes (ECC) from read data output from SPM portion, and provide the read data and ECC values on a port. 
     In a particular embodiment, data processing section  1178 ′ may be formed with programmable circuits, thus enabling different error check and/or correction schemes to be implemented according to application. 
     While embodiments of the invention may include circuits for enabling multi-port communication with an SPM portion, other embodiments may additionally include circuits that control how (or if) an SPM portion is accessed via any of multiple ports. Two such embodiments will now be described with reference to  FIGS. 12A and 12B . 
     Referring now to  FIGS. 12A to 12C , memory devices according to further embodiments are shown in block schematic diagrams and designated by the general reference characters  1200 -A to  1200 -C, respectively. Memory devices  1200 -A to  1200 -C may each include an SPM portion  1202  and a port expansion portion  1204 . An SPM portion  1202  may take the form of SPM portions shown in other embodiments herein, and equivalents. Port expansion portions  1204  and  1204 ′ may include I/F circuits  1226 - 0 / 1  and access logic  1220  as shown in other embodiments, or equivalents. Port expansion portions  1204  and  1204 ′ may also include data access sections  1284 ,  1284 ′  1284 - 0  and/or  1284 - 1 . 
     Referring to  FIG. 12A , a data access section  1284  of memory device  1200  may include an authentication circuit  1286 - 0  and secure access path  1286 - 1 . In one embodiment, an authentication circuit  1286 - 0  may execute an authentication operation on predetermined data with a secure key, or the like, and compare such an authentication result to a received authentication value from a device external to memory device  1200 . If such values match, authentication circuit  1286 - 0  may enable secure access path  1286 - 1 , thereby enabling accesses to SPM portion  1202 . However, if authentication values do not match, authentication circuit  1286 - 0  may disable secure access path  1286 - 1 , thereby preventing accesses to SPM portion  1202 . 
     In a particular embodiment, data access section  1284  may be formed with programmable circuits, thus enabling different authentication schemes to be implemented according to application. 
     Referring to  FIG. 12B , a data access section  1284 ′ of memory device  1200 ′ may include an address control circuit  1288 . An address control circuit  1288  may logically partition areas of SPM portion  1202 . In the embodiment shown, command and address data received from a port (e.g.,  1208 - 0 / 1 ) may be altered by address control circuit  1288  to direct accesses to SPM locations. Further, an address control circuit  1288  may accessed through a “master” port (in this embodiment PORT 1 ) to be placed in a particular configuration. According to such a configuration, port accesses may be restricted, including being unable to access particular sections of SPM portion  1202 , or only being able to perform certain operations (e.g., reads and not writes) at particular locations within SPM portion  1202 . 
     In a particular embodiment, data access section  1284 ′ may be formed with programmable circuits, thus enabling different partitioning schemes to be implemented according to application. Referring to  FIG. 12C , a data access section  1284  of memory device  1200  may include a built-in-self-test (BIST) circuit  1284 - 0  and/or a redundancy circuit  1284 - 1 . A BIST circuit  1284 - 0  may execute self-test operations on SPM section  1202  over single port connection  1202 . In the embodiment shown, BIST circuit  1284 - 0  may also be accessed over port  1208 - 0 . In a very particular embodiment, a BIST circuit  1284 - 0  may write data into locations of SPM portion  1202  according test patterns, and then read such data and compare it to expected data values. Results of such tests may be output over  1208 - 0 . 
     A redundancy circuit  1284 - 1  may include a remapping circuit  1283  and a redundancy memory  1285 . A remapping circuit  1283  may compare a received address to known addresses of defective locations indicated by redundancy memory  1285 , and access a redundant location instead of the defective location. 
     In a particular embodiment, data access sections  1284 - 0  and/or  1284 - 1  may be formed with programmable circuits, thus enabling different BIST or redundancy schemes to be implemented according to application. 
     In particular embodiments, the memory devices of  FIGS. 11A to 12C  may particular implementations of those shown in  FIGS. 1A to 9 . It is noted that the particular embodiments of  FIGS. 11A to 12C  show but a few of the possible different examples of functions that may be added by a port expansion. It is understood that other embodiments may include various other circuits. 
     In this way, a memory device may include an SPM portion and port expansion portion having data processing and/or data access circuits. 
     Embodiments of the invention may also include various methods. Examples of such embodiments will now be described with reference to a number of flow diagrams. 
     Referring to  FIG. 13 , a method  1300  according to one embodiment may include forming a first integrated circuit (IC) portion having one or more single port memories (box  1303 ). A method  1300  may also include forming a second IC portion having two or more ports in communication with a single port of the first IC portion (box  1305 ). 
     Referring to  FIG. 14 , a method  1400  according to another embodiment may include forming a first IC portion having one or more single port memories in a substrate (box  1407 ). In addition, a second IC portion, having two or more ports in communication with a single port of the first IC portion, may be formed in the same substrate (box  1409 ). 
     Referring to  FIG. 15 , a method  1500  according to another embodiment may include forming a first IC portion having one or more single port memories in a substrate (box  1511 ). A second IC portion having two or more ports in communication with a single port of the first IC portion may be formed in a different substrate (box  1513 ). The first and second IC portions may be formed in a same IC package (box  1515 ). 
     Referring now to  FIG. 16 , a method according to yet another embodiment is shown in a flow diagram and designated by the general reference character  1600 . A method  1600  may include forming a first IC portion having one or more single port memories in a substrate (box  1617 ). A second IC portion may be formed that includes programmable circuits (box  1619 ). Programmable circuits may be configured to form two or more ports in communication with a single port of the first IC portion (box  1621 ). Optionally, a method  1600  may include configuring programmable circuits to form data processing circuits between the single port of the 1 st  IC portion and the two or more ports of the second IC portion (box  1623 ). In addition or alternatively, a method  1600  may optionally include configuring programmable circuits to form data access circuits between the single port of the 1 st  IC portion and the two or more ports of the second IC portion (box  1625 ). 
     Referring to  FIG. 17 , a further method according to an embodiment is shown in flow diagram and designated by the general reference character  1700 . A method  1700  may include a programmable device portion  1727  and a substantially non-programmable device portion  1729 . A programmable device portion  1727  may include forming first IC portions having one or more single port memories in a substrate (box  1731 ). Second IC portions may be formed that includes programmable circuits (box  1733 ). Design data may then be created for a circuit having 2+ ports in communication with a single port (box  1735 ). Configuration data may then be generated form the design data that is compatible with the programmable circuits of the second IC portion (box  1737 ). Programmable circuits may then be programmed with the configuration data (box  1739 ). Multi-port memory devices may be formed with first and second IC portions (box  1741 ). 
     In this way, multi-port memory device may be formed with IC portions having programmable circuits. 
     Referring still to  FIG. 17 , a substantially non-programmable device portion  1729  may include generating physical circuit design data from the design data used to program the programmable circuits (box  1743 ). Third IC portions may then be formed with the physical circuit design data (box  1745 ). Multi-port memory devices may be formed with first and third IC portions (box  1747 ). 
     In this way, multi-port memory device may be formed with one IC portion having an SPM memory, and another IC portion with a circuit design used to program other devices. 
     Referring now to  FIG. 18 , another multi-port memory device according to a further embodiment is shown in a block schematic diagram and designated by the general reference character  1800 . In the particular embodiment shown, a port expansion portion  1804  may include “n+1” ports, each of which may transmit data at a maximum bandwidth BW_Px, (where “x” is a port number). Bandwidth values BW_Px, may be the same or may be different. 
     An SPM section  1802  may be capable of a bandwidth (BW_SP) with respect to port expansion portion  1804  equal to or greater than a total of all the maximum bandwidths of the ports together. 
     In this way, a bandwidth between a single memory section and a port expansion portion may be greater than or equal to the bandwidth on all ports together. 
     Referring now to  FIG. 19 , a timing diagram shows one very particular example of read latency in one very particular embodiment. The timing diagram of  FIG. 19  shows commands and data on four different ports (PORT 0  to PORT 3 ), as well as operations within an SPM portion (SP MEM) accessed by such ports. 
       FIG. 19  shows a minimum time between commands (tcmin) for each port, and how such a value may be selected according to a worst case port access case. In the embodiment shown it is assumed that each port may read data in four value bursts. Thus, a worst case read access may result when all ports request a four value burst substantially simultaneously. As shown, a value tcmin may be selected to ensure that the SPM portion may service such a worst case request before outputting data for a subsequent request. 
     In particular, at time t 0  each port may receive a four burst read request (RD 0  to RD 3 ). 
     Starting at time t 1 , such read requests may serviced within SPM portion in a sequence RD 0 , RD 1 , RD 2 , RD 3  to output four data bursts in a corresponding sequence (D 00 -D 03 , D 10 -D 13 , D 20 -D 23 , D 30 -D 33 ). 
     A port expansion portion may provide such data values on the ports at about time t 2 . 
     As shown, to ensure an SPM portion has sufficient bandwidth to service the request, a second read request on PORT 0  may be issued until after a time tcmin. 
     Referring now to  FIG. 20 , a timing diagram shows one very particular example of an alternate read latency in one very particular embodiment. The timing diagram of  FIG. 20  shows the same ports and SPM portion as  FIG. 19 . However, unlike  FIG. 19 , two ports (PORT 1  and PORT 3 ) may receive write commands at time to. 
       FIG. 20  shows an example of a SPM portion that may be a quad data rate type memory device in which write requests may be serviced concurrently with read requests. Accordingly, if port accesses types are varied (e.g., at least one port writes or is idle) a minimum time between commands may be reduced. 
     Referring now to  FIG. 21 , an integrated circuit device according to another embodiment is shown in a block schematic diagram and designated by the general reference character  2100 . The embodiment of  FIG. 21  may be one very particular implementation of that shown in  FIG. 1 . 
     A device  2100  may include a burst access memory portion  2190  and a port expansion portion  2104 . A burst access memory portion  2190  may include a memory cell array  2192 , burst access circuits  2196 , and optionally, memory registers  2194 . A memory cell array  2192  may include storage locations that store data in data units. A data unit may be a multi-bit data value, such as a byte (8-bits), word (16-bits), double word (32-bits), or larger values. Burst access circuits  2196  may transfer data units in bursts between memory cell array  2192  and port expansion portion  2104 . Such a burst access may access related addresses sequentially in an automated fashion. In one embodiment, related addresses may include a base address and one or more next numerical addresses. However, other embodiments may generate an address sequence according to other sequences, and may include operations on an address (e.g., adding/subtracting an offset, hashing function, etc.). Accordingly, a burst access may access a number of addressable locations based on a single base address. 
     Optional memory registers  2194  may store multiple data units received in a burst sequence from burst access circuits  2196  for subsequent writing into memory cell array  2192 . In addition or alternatively, memory registers  2194  may store multiple data units for subsequent output with a burst sequence from burst access circuits  2196 . 
     A port expansion portion  2104  may include two or more ports  2108 - 0  to -n, interfaces  2146 - 0  to -n corresponding to the ports, access logic  2120 , and a register section  2198 . Ports ( 2108 - 0  to -n) and interfaces ( 2146 - 0  to -n) may take the form of embodiments shown above, or equivalents. Access logic  2120  may provide control signals to burst access memory portion  2190  and register section  2198 . 
     A register section  2198  may include a number of burst access registers  2199 - 0  to -n, with one or more such registers corresponding to each port ( 2108 - 0  to -n). Burst access registers ( 2199 - 0  to -n) may each include storage locations for at least a burst sequence of data units, as well as other values as will be described in more detail below. Data transfers between each burst access register ( 2199 - 0  to -n) and a corresponding port ( 2108 - 0  to -n) may be by single data units, in non-burst accesses. That is, one data unit may be received according to one address value. In contrast, data transfers between each burst access register ( 2199 - 0  to -n) and burst access memory portion  2190  may be according to bursts (sequences of two or more) of data units. 
     In this way, an integrated circuit device may include a first IC portion having memory locations accessed according to burst accesses, a second IC portion with registers that access ports in non-burst accesses, but access the first IC portion with burst accesses. 
     Referring now to  FIG. 22 , an integrated circuit device according to a further embodiment is shown in a block diagram and designated by the general reference character  2200 . The embodiment of  FIG. 22  may be one very particular implementation of that shown in  FIG. 21 . A device  2200  may be a first-in-first-out (FIFO) memory device that may output single data units at a read port  2208 - 1  in the same order that such data units are received at a write port  2208 - 0 . 
     A device  2200  may include a burst access memory portion  2290  connected to a port expansion portion  2204  by a write data path  2295 , address/control path  2293 , and a read data path  2291 . In one embodiment, a write data path  2295  may be different from a read data path  2291 . However, in other embodiments, such paths may be the same (e.g., a bi-directional data bus). 
     Port expansion portion  2204  may include a register section  2298  and an access control circuit  2222 . A register section  2298  may include a write burst buffer  2299 - 0  and a read burst buffer  2299 - 1 . A write burst buffer  2299 - 0  may receive data units, in single, non-burst accesses via write port  2208 - 0 . Such data units may be stored in register storage locations  2297 . Data units stored in storage locations  2297  may be transferred to storage locations within burst access memory portion  2290  with a burst write operation that sequentially transfers data units on write data path  2295 . 
     A read burst buffer  2299 - 1  may receive read data with burst read operations that sequentially transfer data units stored in burst access memory portion  2190  on read data path  2291  to corresponding storage locations  2297  within read burst buffer  2299 - 1 . Read burst buffer  2299 - 1  may output data units, in single, non-burst accesses via read port  2208 - 1 . 
     Access control circuit  2222  may receive control and timing signals from write and read ports ( 2208 - 0 / 1 ), and control access to write and read burst buffers ( 2299 - 0 / 1 ). In addition, access control circuit  2222  may generate control and address signals on address/control path  2293 . Access control to write burst buffer  2299 - 0  may include generating one or more write buffer “pointers” (WPB) that identify a particular storage location  2297  within write burst buffer  2299 - 0 . In a similar fashion, access control to read burst buffer  2299 - 1  may include generating one or more read write buffer “pointers” (RPB) that identify a particular storage location  2297  within read burst buffer  2299 - 0 . 
     In this way, a FIFO memory device may include a write buffer that accumulates data units in single access operations and then burst writes such data units into a memory portion. In addition or alternatively, a FIFO memory device may include a read buffer that receives data units in burst read operations from the memory portion then outputs such data units in single access operations. 
     Referring now to  FIGS. 23A to 23H , write operations for a FIFO memory device like that of  FIG. 22  are shown in a sequence of block diagrams.  FIGS. 23A to 23H  show a FIFO memory device  2300  having a burst access memory portion  2390  and write burst buffer  2399 - 0 . Such sections may be like those shown as  2290  and  2299 - 0 , respectively, in  FIG. 22 . In addition, a write buffer pointer (WBP) and pointer trigger  2387  are shown. A write buffer pointer WPB may point to a storage location (e.g., any of  2397 - 0  to - 7 ) to which an incoming write data unit is to be stored. A pointer trigger  2387  represents a pointer position that may result in a burst write of data currently stored within write burst buffer  2399 - 0 . 
     Referring to  FIG. 23A , initially a WBP points to a storage location  2397 - 0 . In addition, pointer trigger  2387  corresponds to storage location  2397 - 4 . A write data unit D 0  is received at write port  2308 - 0 . 
     Referring to  FIG. 23B , data unit D 0  is stored at storage location  2397 - 0 , and WBP advances to storage location  2397 - 1 . Pointer trigger  2387  continues to correspond to storage location  2397 - 4 . A next write data unit D 1  is received at write port  2308 - 0 . 
     Referring to  FIGS. 23C to 23E , data units are stored and a WBP pointer advanced in the same fashion, until WPB corresponds to pointer trigger  2387 , represented by the bold arrow in  FIG. 23E . 
     Referring to  FIG. 23F , in response to a WBP value corresponding to pointer trigger, a burst write operation may occur, storing data units D 0 , D 1 , D 2  and D 3  within burst access memory portion  2390  by way of a write data path  2395 . It is understood that such a burst write occurs in a sequential fashion, with data units D 0 -D 3  following one another (though not necessarily in a particular numerical order). In addition, a pointer trigger  2387  is advanced to a next location. Because a write burst buffer  2399 - 0  is circular buffer, such a location may correspond to storage location  2397 - 0 . 
     Referring to  FIG. 23G , data values D 4 -D 7  may be received in single unit data transfers and stored by advancing a WBP as described above, until the WBP once again corresponds to pointer trigger  2387 , as shown in  FIG. 23G . 
     Referring to  FIG. 23H , in response to a WBP value corresponding to the pointer trigger, a burst write operation may occur once again, storing data values D 4 -D 7  within burst access memory portion  2390 , and a pointer trigger  2387  may be advanced once again. 
     Such operations may repeat to accumulate data units one-by-one, and then burst write them into a memory portion. 
     In this way, a FIFO memory device may have a write buffer pointer, and burst write data values to memory locations when the write buffer pointer advances a predetermined amount and/or predetermined number of times. 
     Referring now to  FIGS. 24A to 24C , read operations for a FIFO memory device like that of  FIG. 22  are shown in a sequence of block diagrams.  FIGS. 24A to 24C  show a FIFO memory device  2400  having a burst access memory portion  2490  and read burst buffer  2499 - 1 . Such sections may be like those shown as  2290  and  2299 - 1 , respectively, in  FIG. 22 . In addition, a read buffer pointer (RBP) and pointer trigger  2487  are shown. A read buffer pointer RPB may point to a storage location (e.g., any of  2497 - 0  to - 7 ) from which a stored data unit is to be output on a read port  2408 - 1 . A pointer trigger  2487  represents a pointer position that may result in a burst read of data stored in burst access memory portion  2490  into read burst buffer  2499 - 1 . 
     Referring to  FIG. 24A , a burst access memory portion  2490  may store a number of data units shown as D 0  to D 11 . Previous burst read operations (and or “fall through” operations described below), may result in data units D 0  to D 7  being stored in storage locations  2497 - 0  to - 7 . Initially a RBP points to a storage location  2497 - 0 . In addition, pointer trigger  2487  corresponds to storage location  2497 - 4 . In response to the RBP, data unit D 0  stored at storage location  2497 - 0  may be output in a non-burst, singe data unit read operation at read port  2408 - 1 . 
     Referring to  FIG. 24B , data units may continue to be output and RBP pointer advanced in the same fashion. 
     Referring to  FIG. 24C , in response to a RBP value corresponding to pointer trigger  2487  (represented by a bold arrow), a burst read operation may occur. In the example shown, such a burst read operation reads data units D 8 , D 9 , D 10  and D 11  stored within burst access memory portion  2490 , via read data path  2491  into storage locations  2497 - 0  to - 3 , respectively. It is understood that such a burst read occurs in a sequential fashion, with data units D 8 -D 11  following one another (though not necessarily in a particular numerical order). In addition, a pointer trigger may be advanced to a next location (not shown). 
     Such operations may repeat to accumulate data units in burst read operations from a memory portion, and output them one-by-one on a read port. 
     In this way, a FIFO memory device may have a read buffer pointer, and burst read data values to buffer locations when the read buffer pointer advances a predetermined amount and/or predetermined number of times. 
     Referring now to  FIGS. 25A to 25E , a “fall through” operation of a FIFO memory device like that of  FIG. 22  according to one embodiment is shown in a sequence of block diagrams. A “fall through” operation may allow one or more initial data units to be read out of a burst buffer. 
       FIGS. 25A to 25E  show a FIFO memory device  2500  having a burst access memory portion  2590 , a write burst buffer  2599 - 0 , and a read burst buffer  2599 - 1 . Such sections may be like those shown as  2290 ,  2299 - 0  and  2299 - 1 , respectively, in  FIG. 22 . 
       FIGS. 25A to 25E  also show a read buffer pointer (RBP), write pointer buffer (WPB), write pointer trigger  2587 - 0 , and read pointer trigger  2587 - 1 , which may operate as described in embodiments above. 
     Referring to  FIG. 25A , a write burst buffer  2599 - 0  may receive an initial data unit D 0 , and store it in a location indicated by write buffer pointer WBP. 
     Referring to  FIG. 25B , unlike previously described write operations, an initial data unit D 0  may be output through read port  2508 - 1 , without being written as part of burst sequence into a burst access memory portion  2590  (not shown in  FIGS. 25A and 25B ). Such a read operation may be directly from write burst buffer  2599 - 0 , or alternatively, from write burst buffer  2599 - 0  through read burst buffer  2599 - 1 . In one particular embodiment, a read buffer pointer (RPB) may have an initial value, signifying that no data units have yet been read into the read burst buffer  2599 - 1 . At the same time, additional data units D 1 -D 3  may continue to be accumulated within write burst buffer  2599 - 0 . 
     Referring to  FIG. 25C , in response to a WBP value corresponding to pointer trigger  2587 - 0  (represented by a bold arrow), a burst write operation may occur, writing data units D 1 -D 4  into burst access memory portion  2590 . Data units (e.g., D 5 ) may continue to be accumulated within write burst buffer  2599 - 0 . 
     Referring to  FIG. 25D , as data units (e.g., D 6 ) continue to be accumulated, a burst read operation may burst write data values D 1 -D 4  from burst access memory portion  2491  into read burst buffer  2599 - 1 . 
     Referring to  FIG. 25E , in response to receiving a first read burst of data, a RBP may point to a first storage location (corresponding to data unit D 1 ), and subsequent read operations may read single data units, one-by-one, from read burst buffer  2599 - 1 . In addition, a read pointer trigger  2587 - 1  may be set to an appropriate storage location (corresponding to data unit D 4 , in the embodiment shown). 
     Referring now to  FIGS. 26A to 26D , “fall through” operations of a FIFO memory device like that of  FIG. 22  according to another embodiment is shown in a sequence of block diagrams. 
       FIGS. 26A to 26D  show a FIFO memory device  2600  having a burst access memory portion  2690 , a write burst buffer  2699 - 0 , and a read burst buffer  2699 - 1 . Such sections may be like those shown as  2290 ,  2299 - 0  and  2299 - 1 , respectively, in  FIG. 22 . 
       FIGS. 26A to 26D  also show a read buffer pointer (RBP), write pointer buffer (WPB), write pointer trigger  2687 - 0 , and read pointer trigger  2687 - 1 , which may operate as described in embodiments above. 
     Referring to  FIG. 26A , an initial data unit D 0  may be received at a write port  2608 - 0 . Unlike previously described write operations, an initial data unit D 0  may be stored in read burst buffer  2699 - 1  without being written as part of burst sequence into a burst access memory portion  2690  (not shown in  FIGS. 26A and 26B ). Such a storing of initial data unit D 0  may be directly to read burst buffer  2699 - 1  from write port  2608 - 0 , or alternatively, through write burst buffer  2699 - 0 . In one particular embodiment, a write buffer pointer (WPB) may have an initial value, signifying that only initial data unit(s) have been received. A read buffer pointer (RPB) and read pointer trigger  2687 - 1  may be established as described in above embodiments. 
     Referring to  FIG. 26B , in response to receiving an initial data unit(s) D 0 , a WPB and write pointer trigger  2687 - 0  may be established. Thus, write data units may start to be accumulated within write burst buffer  2699 - 0 . As shown in  FIG. 26B , a received data unit D 1  may be stored as indicated by WBP, and not directly stored in read burst buffer  2699 - 1 . 
     Referring to  FIG. 26C , in response to a WBP value corresponding to write pointer trigger  2687 - 0  (represented by a bold arrow), a burst write operation may occur, writing data units D 1 -D 4  into burst access memory portion  2690 . Data units (e.g., D 5 ) may continue to be accumulated within write burst buffer  2699 - 0 . 
     Referring to  FIG. 26D , as data units (e.g., D 6 ) continue to be accumulated, a burst read operation may burst write data values D 1 -D 4  from burst access memory portion  2490  into read burst buffer  2699 - 1 . In the particular embodiment shown, initial data unit D 0  may be read out on read data path  2608 - 1 . Consequently, RBP may advance to a next storage location (corresponding to data unit D 1 , in the embodiment shown). Subsequent read operations may continue reading single data units, one-by-one, from read burst buffer  2699 - 1 . 
     While the embodiment shows the fall through of a first initial data unit (D 0 ), alternate embodiments may allow larger numbers of data units to be read from a burst register without being written to a memory portion in a burst write access. 
     Referring now to  FIG. 27 , an integrated circuit device according to a further embodiment is shown in a block diagram and designated by the general reference character  2700 . The embodiment of  FIG. 27  may be one very particular implementation of that shown in  FIG. 21 . A device  2700  may be a multi-port memory device that may read or write single data units at any of multiple ports (two shown as  2708 - 0 / 1 ). 
     A device  2700  may include a burst access memory portion  2790  connected to a port expansion portion  2704  by a write data path  2795 , address path  2793 - 0 , control path  2793 - 1 , and a read data path  2791 . As in the case of  FIG. 22 , in one embodiment, a write data path  2795  may be different from a read data path  2791 . However, in other embodiments, such paths may be the same (e.g., a bi-directional data bus). 
     Port expansion portion  2704  may include a register section  2798  and an access control circuit  2722 . A register section  2798  may include write access registers  2799 - 0  connected to each port (e.g.,  2708 - 0 / 1 ), as well as read access registers  2799 - 1  connected to each port (e.g.,  2708 - 0 / 1 ). Thus, unlike the FIFO device, write and read access registers  2799 - 0 / 1  are common to each port. 
     A write access register  2799 - 0  may include particular storage locations accessed when a write operation occurs at a particular port. In the embodiment shown, each write register for a given port may include an external address store location (Ext. Add. Reg.), a write data store location (DWR), burst data store locations (DBrst 1  to Dbrst 4 ), and optionally, a base address store location (Base Add). A write address received at a port (e.g.,  2708 - 0  or - 1 ) in a non-burst access may be stored in location Ext. Add. Reg. Similarly, a write data unit received at a port (e.g.,  2708 - 0  or - 1 ) in a non-burst access may be stored in location DWR. In addition, data units stored in storage locations DBrst 1  to Dbrst 4  may be transferred to storage locations within burst access memory portion  2790  with a burst write operation. In addition, data units stored in burst access memory portion  2790  may be burst read into storage locations DBrst 1  to Dbrst  4 . 
     A read access register  2799 - 1  may include particular storage locations accessed when a read operation occurs at a particular port. In the embodiment shown, each read register for a given port may include an external address store location (Ext. Add. Reg.), burst data store locations (DBrst 1  to Dbrst 4 ), and optionally, a base address store location (Base Add). A read address received at a port (e.g.,  2708 - 0  or - 1 ) in a non-burst access may be stored in location Ext. Add. Reg. Data units stored in burst access memory portion  2790  may be burst read into storage locations DBrst 1  to Dbrst  4  of read access registers  2799 - 1 . 
     Access control circuit  2722  may receive control and timing signals from ports ( 2708 - 0 / 1 ), and control access to write and read access registers ( 2799 - 0 / 1 ). In addition, access control circuit  2722  may generate control signals on control path  2793 - 1 , and apply addresses on address path  2793 - 0  from values stored in read and write access registers  2799 - 0 / 1 . Access control circuit  2722  may also selectively modify values stored in storage locations DBrst 1 - 4  of write access registers  2799 - 0 . 
     In the embodiment shown, a port expansion portion  2704  may also include a data selector circuit  2783 . A data selector circuit  2783  may output one data unit from those stored in locations DBurst 1 - 4  of read access registers  2799 - 1 . 
     In this way, a multi-port memory device may include write access registers that may receive data in single units from ports, but write data units in bursts to a memory portion. In addition or alternatively, a multi-port memory device may include read access registers that receive read data units in bursts from a memory portion, but output single read data units on ports, in non-burst accesses. 
     Referring now to  FIG. 28 , modification circuits according to an embodiment is shown in a block schematic diagram. Modification circuits may include a write access register  2899 - 0  and an access control circuit  2822 . In one embodiment, such items may correspond to those shown as  2799 - 0  and  2722  in  FIG. 27 . 
     Access control circuit  2822  may include control circuits  2881  that generate register address values REG. ADD that may be applied to write access register  2899 - 0  to access particular storage locations therein for write and/or read operations. A modification register  2885 , controlled by control circuits  2881 , may serve as a temporary store to store data values read from write access register. 
     In one particular operation, control circuits  2881  may read at least a portion of write address value (value at storage location Ext. Add. Reg.) and read a write data unit (data unit stored at location DWR) into modification register  2885 . According to the address value portion, control circuit  2881  may write the write data unit from modification register  2885  into one of the storage locations DBrst 1 - 4  of the same write access register  2899 - 0 , thus over-writing any data unit value stored at the location. 
     In this way, one data unit from a sequence of data units stored in a write access register may be modified according to a received write data unit. 
     Referring now to  FIGS. 29A to 29D , write operations for a multi-port memory device like that of  FIG. 27  are shown in a sequence of block diagrams.  FIGS. 29A to 29D  show a multi-port memory device  2900  having a burst access memory portion  2990  and a write burst buffer  2999 - 0 . Such sections may be like those shown as  2790  and  2799 - 0 , respectively, in  FIG. 27 . 
     Referring to  FIG. 29A , in response to a write operation, a write address ([ADDx]:[1:0]) and write data unit Dz may be received. The write address ([ADDx]:[1:0]) may be stored in storage location Ext. Add. Reg. corresponding to the port receiving the write request. Write data unit Dz may be stored in location DWR corresponding to the port receiving the write request. In the embodiment shown, a write address ([ADDx]:[1:0]) may include a base address portion [ADDx] and a burst portion[1:0]. A base address portion [ADDx] may be more significant bits (MSBs) of an address while burst portion[1:0] may be the least significant bits (LSBs) of an address. 
     Referring to  FIG. 29B , a base address [ADDx] may be extracted from a write address value with an address extraction operation  2977  and stored in location [Base Add] corresponding to the port requesting the write operation. Such a base address value [ADDx] may be applied to burst access memory device  2990  as a base address for a burst read access (e.g., starting at [ADDx]:[00], and bursting through [ADDx]:01], [ADDx]:10], [ADDx]:11]). In an alternate embodiment, a base address may be applied from location Ext. Add. Reg. 
     Referring still to  FIG. 29B , in response to the base address, a burst sequence of data (Da, Db, Dc, Dd) corresponding to the base address may be sequentially output from burst access memory device  2990  and stored in locations Dbrst 1 - 4 , respectively. 
     Referring to  FIG. 29C , each of data locations DBrst 1 - 4  may be conceptualized as corresponding to LSB values 00, 01, 10 and 11, respectively. As shown in  FIG. 29C , a data unit corresponding to the LSBs of the write address may be modified to store the write data unit (Dz) according to such LSB. Thus, in the example shown, write data unit Dz may be written into location DBrst 2 , replacing data unit Db. 
     Referring to  FIG. 29D , a base address [ADDx] may again be applied to burst access memory device  2990 , but this time as a base address for a burst write access. As in the case of  FIG. 29B , in an alternate embodiment, a base address may be applied from location Ext. Add. Reg. In response to such a write base address, a burst sequence of modified data (Da, Dz, Dc, Dd) corresponding to the base address may be sequentially written into burst access memory device  2990  from locations Dbrst 1 - 4 , respectively, of write access register  2999 - 0 . 
     In this way, a multi-port memory device may burst read data from a memory portion in response to a write operation, modify one data unit of the burst, and then burst write the modified data back into the memory portion. 
     Referring now to  FIGS. 30A to 30D , read operations for a multi-port memory device like that of  FIG. 27  are shown in a sequence of block diagrams.  FIGS. 30A to 30D  show a multi-port memory device  3000  having a burst access memory portion  3090  and a read burst buffer  3099 - 1 . Such sections may be like those shown as  2790  and  2799 - 1 , respectively, in  FIG. 27 . 
     Referring to  FIG. 30A , in response to a read operation, a read address ([ADDx]:[1:0]) may be received. The read address ([ADDx]:[1:0]) may be stored in storage location Ext. Add. Reg. corresponding to the port receiving the read request. As in the case of  FIGS. 29A to 29D , a read address ([ADDx]:[1:0]) may include a base address portion [ADDx] and a burst portion[1:0]. 
     Referring to  FIG. 30B , a base address [ADDx] may be extracted from a read address value with an address extraction operation  3077 , in the same or equivalent fashion, as described in  FIG. 29B . 
     Referring to  FIG. 30C , base address value [ADDx] may be applied to burst access memory portion  3090  as a base address for a burst read access. In an alternate embodiment, a base address may be applied from location Ext. Add. Reg. In response to the base address, a burst sequence of data (Da, Db, Dc, Dd) corresponding to the base address may be sequentially output from burst access memory device  3090  and stored in locations Dbrst 1 - 4 , respectively. 
     Referring to  FIG. 30D , like  FIGS. 29A to 29D , each of data locations DBrst 1 - 4  may be conceptualized as corresponding to LSB values 00, 01, 10 and 11 respectively. As shown in  FIG. 30D , a data unit corresponding to the LSBs of the read address may be selected for output by data selector circuit  3083 . Thus, in the example shown, read data unit Dc may be output on the port requesting the read operation. 
     In this way, a multi-port memory device may burst read data from a memory portion in response to a read operation, but output one data unit of the burst based on a portion of the read address. 
     It should be appreciated that in the foregoing description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention. 
     It is also understood that the embodiments of the invention may be practiced in the absence of an element and/or step not specifically disclosed. That is, an inventive feature of the invention may be elimination of an element. 
     Accordingly, while the various aspects of the particular embodiments set forth herein have been described in detail, the present invention could be subject to various changes, substitutions, and alterations without departing from the spirit and scope of the invention.