ADVANCE INFORMATION 2.5V MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 bits and 2,359,296 bits • • FEATURES: • • • • • • • • • • • • • • Choose from among the following memory density options: IDT72T51546 Total Available Memory = 1,179,648 bits IDT72T51556 Total Available Memory = 2,359,296 bits Configurable from 1 to 32 Queues Queues may be configured at master reset from the pool of Total Available Memory in blocks of 256 x 36 Independent Read and Write access per queue User programmable via serial port User selectable I/O: 2.5V LVTTL, 1.5V HSTL, 1.8V eHSTL Default multi-queue device configurations – IDT72T51546 : 1,024 x 36 x 32Q – IDT72T51556 : 2,048 x 36 x 32Q 100% Bus Utilization, Read and Write on every clock cycle 200 MHz High speed operation (5ns cycle time) 3.6ns access time Echo Read Enable & Echo Read Clock Outputs Individual, Active queue flags (OV, FF, PAE, PAF, PR) 8 bit parallel flag status on both read and write ports Shows PAE and PAF status of 8 Queues • • • • • • • • • • IDT72T51546 IDT72T51556 Direct or polled operation of flag status bus Global Bus Matching - (All Queues have same Input Bus Width and Output Bus Width) User Selectable Bus Matching Options: – x36in to x36out – x18in to x36out – x9in to x36out – x36in to x18out – x36in to x9out FWFT mode of operation on read port Packet mode operation Partial Reset, clears data in single Queue Expansion of up to 8 multi-queue devices in parallel is available Power Down Input provides additional power savings in HSTL and eHSTL modes. JTAG Functionality (Boundary Scan) Available in a 256-pin PBGA, 1mm pitch, 17mm x 17mm HIGH Performance submicron CMOS technology Industrial temperature range (-40°C to +85°C) is available FUNCTIONAL BLOCK DIAGRAM MULTI-QUEUE FLOW-CONTROL DEVICE FSTR WRADD 8 WEN WCLK Q0 READ CONTROL WRITE CONTROL WADEN Q1 RADEN ESTR RDADD 8 REN RCLK EREN ERCLK Q2 Qout Din PAF PAFn 8 WRITE FLAGS FF x36 DATA OUT OV READ FLAGS x36 DATA IN OE Q31 PR PAE PAEn 8 PRn 5998 drw01 IDT and the IDT logo are registered trademarks of Integrated Device Technology, Inc COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES NOVEMBER 2003 1 2003 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice. DSC-5998/3 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits DESCRIPTION: The IDT72T51546/72T51556 multi-queue flow-control devices is a single chip within which anywhere between 1 and 32 discrete FIFO queues can be setup. All queues within the device have a common data input bus, (write port) and a common data output bus, (read port). Data written into the write port is directed to a respective queue via an internal de-multiplex operation, addressed by the user. Data read from the read port is accessed from a respective queue via an internal multiplex operation, addressed by the user. Data writes and reads can be performed at high speeds up to 200MHz, with access times of 3.6ns. Data write and read operations are totally independent of each other, a queue maybe selected on the write port and a different queue on the read port or both ports may select the same queue simultaneously. The device provides Full flag and Output Valid flag status for the queue selected for write and read operations respectively. Also a Programmable Almost Full and Programmable Almost Empty flag for each queue is provided. Two 8 bit programmable flag busses are available, providing status of queues not selected for write or read operations. When 8 or less queues are configured in the device these flag busses provide an individual flag per queue, when more than 8 queues are used, either a Polled or Direct mode of bus operation provides the flag busses with all queues status. Bus Matching is available on this device, either port can be 9 bits, 18 bits or 36 bits wide provided that at least one port is 36 bits wide. When Bus Matching is used the device ensures the logical transfer of data throughput in a Little Endian manner. A packet mode of operation is also provided when the device is configured for 36 bit input and 36 bit output port sizes. The Packet mode provides the user with a flag output indicating when at least one (or more) packets of data within a queue is available for reading. The Packet Ready provides the user with a means by which to mark the start and end of packets of data being passed through the queues. The multi-queue device then provides the user with an internally generated packet ready status per queue. COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES The user has full flexibility configuring queues within the device, being able to program the total number of queues between 1 and 32, the individual queue depths being independent of each other. The programmable flag positions are also user programmable. All programming is done via a dedicated serial port. If the user does not wish to program the multi-queue device, a default option is available that configures the device in a predetermined manner. Both Master Reset and Partial Reset pins are provided on this device. A Master Reset latches in all configuration setup pins and must be performed before programming of the device can take place. A Partial Reset will reset the read and write pointers of an individual queue, provided that the queue is selected on both the write port and read port at the time of partial reset. Echo Read Enable, EREN and Echo Read Clock, ERCLK outputs are provided. These are outputs from the read port of the Queue that are required for high speed data communication, to provide tighter synchronization between the data being transmitted from the Qn outputs and the data being received by the input device. Data read from the read port is available on the output bus with respect to EREN and ERCLK, this is very useful when data is being read at high speed. The multi-queue flow-control device has the capability of operating its IO in either 2.5V LVTTL, 1.5V HSTL or 1.8V eHSTL mode. The type of IO is selected via the IOSEL input. The core supply voltage (VCC) to the multi-queue is always 2.5V, however the output levels can be set independently via a separate supply, VDDQ. The devices also provide additional power savings via a Power Down Input. This input disables the write port data inputs when no write operations are required. A JTAG test port is provided, here the multi-queue flow-control device has a fully functional Boundary Scan feature, compliant with IEEE 1149.1 Standard Test Access Port and Boundary Scan Architecture. See Figure 1, Multi-Queue Flow-Control Device Block Diagram for an outline of the functional blocks within the device. 2 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits D35 = TEOP D34 = TSOP Din x9, x18, x36 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES 2 D0 - D35 WCLK WEN TMS INPUT DEMUX JTAG Logic WRADD WADEN TDI TDO TCK 8 Write Control Logic TRST Write Pointers Packet Mode Logic FSTR PAFn FSYNC 8 PAF General Flag Monitor Upto 32 FIFO Queues FXO FXI FF PAF SI SO SCLK SENI SENO FM IW OW BM Serial Multi-Queue Programming Vref PD ESTR ESYNC EXI EXO 8 Reset Logic Read Control Logic RDADD RADEN NULL-Q REN RCLK Device ID 3 Bit OUTPUT MUX PAE/ PAF Offset 2 OUTPUT REGISTER PRS MRS IOSEL OV PAE Read Pointers PKT DFM PRn/PAEn PAE General Flag Monitor MAST ID0 ID1 ID2 DF 8 Active Q Flags 2.3 Mbit Dual Port Memory Active Q Flags PR Q35 = REOP Q34 = RSOP EREN ERCLK IO Level Control & Power Down OE Q0 - Q35 Qout x9, x18, x36 Figure 1. Multi-Queue Flow-Control Device Block Diagram 3 5998 drw02 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES PIN CONFIGURATION A1 BALL PAD CORNER A D14 D13 D12 D10 D7 D4 D1 TCK TDO ID1 Q3 Q6 Q9 Q12 Q14 Q15 D15 D16 D11 D9 D6 D3 D0 TMS TDI ID0 Q2 Q5 Q8 Q11 Q13 Q19 D17 D18 D19 D8 D5 D2 TRST IOSEL ID2 Q0 Q1 Q4 Q7 Q10 Q17 Q18 D20 D21 D23 D24 D26 D27 D29 D30 D32 D33 GND NULL-Q PD GND SI DFM SENO SENI B C D E C N N O I A T V A D A RM O F IN D22 VDDQ VDDQ VDDQ VCC VCC VCC D25 VDDQ VDDQ VCC VCC GND GND D28 VDDQ VCC GND GND GND D31 VCC VCC GND GND D34 VCC GND GND D35 VCC GND VREF VCC DF VDDQ VDDQ VDDQ Q16 Q21 Q20 VCC VCC VDDQ VDDQ Q24 Q23 Q22 GND GND GND VCC VDDQ Q27 Q26 Q25 GND GND GND GND VCC VCC Q30 Q29 Q28 GND GND GND GND GND GND VCC Q33 Q32 Q31 GND GND GND GND GND GND GND VCC PKT Q35 Q34 VCC GND GND GND GND GND GND VCC VCC GND MAST FM VDDQ VCC GND GND GND GND GND GND VCC VDDQ BM IW SO VDDQ VDDQ VCC VCC GND GND VCC VCC VDDQ VDDQ OE SCLK VDDQ VDDQ VDDQ VCC VCC VCC VCC VDDQ WADEN PAF3 PAF6 PAF7 FF OV PAE PAE7 WRADD6 WRADD5 FSYNC FSTR PAF2 PAF5 PAF4 PAF PR ERCLK WRADD7 FXI FXO PAF0 PAF1 WEN WCLK PRS MRS 1 2 3 4 5 6 7 8 9 E F G H J K L M N WRADD1 WRADD0 P WRADD4 WRADD3 WRADD2 VCC OW RDADD0 RDADD1 VDDQ RDADD2 RDADD3 RDADD4 PAE6 PAE3 RDADD5 RDADD6 RDADD7 EREN PAE5 PAE2 RADEN ESTR ESYNC RCLK REN PAE4 PAE1 PAE0 EXO EXI 10 11 12 13 14 15 16 VDDQ R T 5998 drw03 PBGA (BB256-1, order code: BB) TOP VIEW 4 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES respective queue is selected on the write port, the almost full flag provides status for that queue. Conversely, the read port has an output valid flag, providing status of the data being read from the queue selected on the read port. As well as the output valid flag the device provides a dedicated almost empty flag. This almost empty flag is similar to the almost empty flag of a conventional IDT FIFO. The device provides a user programmable almost empty flag for all 32 queues and when a respective queue is selected on the read port, the almost empty flag provides status for that queue. DETAILED DESCRIPTION MULTI-QUEUE STRUCTURE The IDT multi-queue flow-control device has a single data input port and single data output port with up to 32 FIFO queues in parallel buffering between the two ports. The user can setup between 1 and 32 Queues within the device. These queues can be configured to utilize the total available memory, providing the user with full flexibility and ability to configure the queues to be various depths, independent of one another. PROGRAMMABLE FLAG BUSSES In addition to these dedicated flags, full & almost full on the write port and output valid & almost empty on the read port, there are two flag status busses. An almost full flag status bus is provided, this bus is 8 bits wide. Also, an almost empty flag status bus is provided, again this bus is 8 bits wide. The purpose of these flag busses is to provide the user with a means by which to monitor the data levels within queues that may not be selected on the write or read port. As mentioned, the device provides almost full and almost empty registers (programmable by the user) for each of the 32 queues in the device. In the IDT72T51546/72T51556 multi-queue flow-control devices the user has the option of utilizing anywhere between 1 and 32 queues, therefore the 8 bit flag status busses are multiplexed between the 32 queues, a flag bus can only provide status for 8 of the 32 queues at any moment, this is referred to as a “Quadrant”, such that when the bus is providing status of queues 1 through 8, this is quadrant 1, when it is queues 9 through 16, this is quadrant 2 and so on up to quadrant 4. If less than 32 queues are setup in the device, there are still 4 quadrants, such that in “Polled” mode of operation the flag bus will still cycle through 4 quadrants. If for example only 22 queues are setup, quadrants 1 and 2 will reflect status of queues 1 through 8 and 9 through 16 respectively. Quadrant 3 will reflect the status of queues 17 through 22 on the least significant 6 bits, the most significant 2 bits of the flag bus are don’t care and the 4th quadrant outputs will be don’t care also. The flag busses are available in two user selectable modes of operation, “Polled” or “Direct”. When operating in polled mode a flag bus provides status of each quadrant sequentially, that is, on each rising edge of a clock the flag bus is updated to show the status of each quadrant in order. The rising edge of the write clock will update the almost full bus and a rising edge on the read clock will update the almost empty bus. The mode of operation is always the same for both the almost full and almost empty flag busses. When operating in direct mode, the quadrant on the flag bus is selected by the user. So the user can actually address the quadrant to be placed on the flag status busses, these flag busses operate independently of one another. Addressing of the almost full flag bus is done via the write port and addressing of the almost empty flag bus is done via the read port. MEMORY ORGANIZATION/ ALLOCATION The memory is organized into what is known as “blocks”, each block being 256 x36 bits. When the user is configuring the number of queues and individual queue sizes the user must allocate the memory to respective queues, in units of blocks, that is, a single queue can be made up from 0 to m blocks, where m is the total number of blocks available within a device. Also the total size of any given queue must be in increments of 256 x36. For the IDT72T51546 and IDT72T51556 the Total Available Memory is 128 and 256 blocks respectively (a block being 256 x36). Queues can be built from these blocks to make any size queue desired and any number of queues desired. BUS WIDTHS The input port is common to all queues within the device, as is the output port. The device provides the user with Bus Matching options such that the input port and output port can be either x9, x18 or x36 bits wide provided that at least one of the ports is x36 bits wide, the read and write port widths being set independently of one another. Because the ports are common to all queues the width of the queues is not individually set, so that the input width of all queues are equal and the output width of all queues are equal. WRITING TO & READING FROM THE MULTI-QUEUE Data being written into the device via the input port is directed to a discrete queue via the write queue select address inputs. Conversely, data being read from the device read port is read from a queue selected via the read queue select address inputs. Data can be simultaneously written into and read from the same queue or different queues. Once a queue is selected for data writes or reads, the writing and reading operation is performed in the same manner as a conventional IDT synchronous FIFO, utilizing clocks and enables, there is a single clock and enable per port. When a specific queue is addressed on the write port, data placed on the data inputs is written to that queue sequentially based on the rising edge of a write clock provided setup and hold times are met. Conversely, data is read on to the output port after an access time from a rising edge on a read clock. The operation of the write port is comparable to the function of a conventional FIFO operating in standard IDT mode. Write operations can be performed on the write port provided that the queue currently selected is not full, a full flag output provides status of the selected queue. The operation of the read port is comparable to the function of a conventional FIFO operating in FWFT mode. When a queue is selected on the output port, the next word in that queue will automatically fall through to the output register. All subsequent words from that queue require an enabled read cycle. Data cannot be read from a selected queue if that queue is empty, the read port provides an Output Valid flag indicating when data read out is valid. If the user switches to a queue that is empty, the last word from the previous queue will remain on the output register. As mentioned, the write port has a full flag, providing full status of the selected queue. Along with the full flag a dedicated almost full flag is provided, this almost full flag is similar to the almost full flag of a conventional IDT FIFO. The device provides a user programmable almost full flag for all 32 queues and when a PACKET READY The multi-queue flow-control device also offers a “Packet Mode” operation. Packet Mode is user selectable and requires the device to be configured with both write and read ports as 36 bits wide. In packet mode, users can define the length of packets or frame by using the two most significant bits of the 36-bit word. Bit 34 is used to mark the Start of Packet (SOP) and bit 35 is used to mark the End of Packet (EOP) as shown in Table 5). When writing data into a given queue , the first word being written is marked, by the user setting bit 34 as the “Start of Packet” (SOP) and the last word written is marked as the “End of Packet” (EOP) with all words written between the Start of Packet (SOP) marker (bit 34) and the End of packet (EOP) packet marker (bit 35) constituting the entire packet. A packet can be any length the user desires, up to the total available memory in the multi-queue device. The device monitors the SOP (bit 34) and looks for the word that contains the EOP (bit 35). The read port is supplied with an additional 5 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits status flag, “Packet Ready”. The Packet Ready (PR) flag in conjunction with Output Valid (OV) indicates when at least one packet is available to read. When in packet mode the almost empty flag status , provides packet ready flag status for individual queues. COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES memory blocks within a multi-queue device can be allocated to increase the depth of a queue. For example, depth expansion of 8 devices provides the possibility of 8 queues of 64K x36 deep, each queue being setup within a single device utilizing all memory blocks available to produce a single queue. This is the deepest queue that can setup within a device. For queue expansion a maximum number of 256 (8 x 32) queues may be setup, each queue being 2K x36 deep, if less queues are setup, then more memory blocks will be available to increase queue depths if desired. When connecting multi-queue devices in expansion mode all respective input pins (data & control) and output pins (data & flags), should be “connected” together between individual devices. EXPANSION Expansion of multi-queue devices is also possible, up to 8 devices can be connected in a parallel fashion providing the possibility of both depth expansion or queue expansion. Depth Expansion means expanding the depths of individual queues. Queue expansion means increasing the total number of queues available. Depth expansion is possible by virtue of the fact that more 6 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES PIN DESCRIPTIONS Symbol & Pin No. BM (L14) Name Bus Matching D[35:0] Data Input Bus Din (See Pin No. table for details) I/O TYPE LVTTL INPUT Description This pin is setup before Master Reset and must not toggle during any device operation. This pin is used along with IW and OW to setup the multi-queue flow-control device bus width. Please refer to Table 3 for details. HSTL-LVTTL These are the 36 data input pins. Data is written into the device via these input pins on the rising edge INPUT of WCLK provided that WEN is LOW. Note, that in Packet mode D32-D35 may be used as packet markers, please see packet ready functional discussion for more detail. Due to bus matching not all inputs may be used, any unused inputs should be tied LOW. DF(1) (L3) Default Flag LVTTL INPUT If the user requires default programming of the multi-queue device, this pin must be setup before Master Reset and must not toggle during any device operation. The state of this input at master reset determines the value of the PAE/PAF flag offsets. If DF is LOW the value is 8, if DF is HIGH the value is 128. DFM(1) (L2) Default Mode LVTTL INPUT The multi-queue device requires programming after master reset. The user can do this serially via the serial port, or the user can use the default method. If DFM is LOW at master reset then serial mode will be selected, if HIGH then default mode is selected. ERCLK (R10) RCLK Echo HSTL-LVTTL Read Clock Echo output, this output generates a clock based on the read clock input, this is used for Source OUTPUT Synchronous clocking where the receiving devices utilizes the ERCLK to clock data output from the Queue. EREN (R11) REN Echo HSTL-LVTTL Read Enable Echo output, can be used in conjunction with the ERCLK output to load data output from the OUTPUT Queue into the receiving device. ESTR (R15) PAEn Flag Bus Strobe ESYNC (R16) PAEn Bus Sync HSTL-LVTTL ESYNC is an output from the multi-queue device that provides a synchronizing pulse for the PAEn bus OUTPUT during Polled operation of the PAEn bus. During Polled operation each quadrant of queue status flags is loaded on to the PAEn bus outputs sequentially based on RCLK. The first RCLK rising edge loads quadrant 1 on to PAEn, the second RCLK rising edge loads quadrant 2 and so on. The fifth RCLK rising edge will again load quadrant 1. During the RCLK cycle that quadrant 1 of a selected device is placed on to the PAEn bus, the ESYNC output will be HIGH. For all other quadrants of that device, the ESYNC output will be LOW. EXI (T16) PAEn Bus Expansion In LVTTL INPUT The EXI input is used when multi-queue devices are connected in expansion mode and Polled PAEn bus operation has been selected . EXI of device ‘N’ connects directly to EXO of device ‘N-1’. The EXI receives a token from the previous device in a chain. In single device mode the EXI input must be tied LOW if the PAEn bus is operated in direct mode. If the PAEn bus is operated in polled mode the EXI input must be connected to the EXO output of the same device. In expansion mode the EXI of the first device should be tied LOW, when direct mode is selected. EXO (T15) PAEn Bus Expansion Out LVTTL OUTPUT EXO is an output that is used when multi-queue devices are connected in expansion mode and Polled PAEn bus operation has been selected . EXO of device ‘N’ connects directly to EXI of device ‘N+1’. This pin pulses when device N has placed its final (4th) quadrant on to the PAEn bus with respect to RCLK. This pulse (token) is then passed on to the next device in the chain ‘N+1’ and on the next RCLK rising edge the first quadrant of device N+1 will be loaded on to the PAEn bus. This continues through the chain and EXO of the last device is then looped back to EXI of the first device. The ESYNC output of each device in the chain provides synchronization to the user of this looping event. FF (P8) Full Flag LVTTL INPUT If direct operation of the PAEn bus has been selected, the ESTR input is used in conjunction with RCLK and the RDADD bus to select a quadrant of queues to be placed on to the PAEn bus outputs. A quadrant addressed via the RDADD bus is selected on the rising edge of RCLK provided that ESTR is HIGH. If Polled operations has been selected, ESTR should be tied inactive, LOW. Note, that a PAEn flag bus selection cannot be made, (ESTR must NOT go active) until programming of the part has been completed and SENO has gone LOW. HSTL-LVTTL This pin provides the full flag output for the active Queue, that is, the queue selected on the input port OUTPUT for write operations, (selected via WCLK, WRADD bus and WADEN). On the WCLK cycle after a queue selection, this flag will show the status of the newly selected queue. Data can be written to this queue on the next cycle provided FF is HIGH. This flag has High-Impedance capability, this is important during expansion of devices, when the FF flag output of up to 8 devices may be connected together on a common line. The device with a queue selected takes control of the FF bus, all other devices place their FF output into High-Impedance. When a queue selection is made on the write port this output will switch from High-Impedance control on the next WCLK cycle. This flag is synchronized to WCLK. 7 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES PIN DESCRIPTIONS (CONTINUED) Symbol & Pin No. FM(1) (K16) Name Flag Mode I/O TYPE Description HSTL-LVTTL This pin is setup before a master reset and must not toggle during any device operation. The state of the INPUT FM pin during Master Reset will determine whether the PAFn and PAEn flag busses operate in either Polled or Direct mode. If this pin is HIGH the mode is Polled, if LOW then it will be Direct. FSTR (R4) PAFn Flag Bus Strobe LVTTL INPUT If direct operation of the PAFn bus has been selected, the FSTR input is used in conjunction with WCLK and the WRADD bus to select a quadrant of queues to be placed on to the PAFn bus outputs. A quadrant addressed via the WRADD bus is selected on the rising edge of WCLK provided that FSTR is HIGH. If Polled operations has been selected, FSTR should be tied inactive, LOW. Note, that a PAFn flag bus selection cannot be made, (FSTR must NOT go active) until programming of the part has been completed and SENO has gone LOW. FSYNC (R3) PAFn Bus Sync LVTTL OUTPUT FSYNC is an output from the multi-queue device that provides a synchronizing pulse for the PAFn bus during Polled operation of the PAFn bus. During Polled operation each quadrant of queue status flags is loaded on to the PAFn bus outputs sequentially based on WCLK. The first WCLK rising edge loads quadrant 1 on to PAFn, the second WCLK rising edge loads quadrant 2 and so on. The fifth WCLK rising edge will again load quadrant 1. During the WCLK cycle that quadrant 1 of a selected device is placed on to the PAFn bus, the FSYNC output will be HIGH. For all other quadrants of that device, the FSYNC output will be LOW. FXI (T2) PAFn Bus Expansion In LVTTL INPUT The FXI input is used when multi-queue devices are connected in expansion mode and Polled PAFn bus operation has been selected . FXI of device ‘N’ connects directly to FXO of device ‘N-1’. The FXI receives a token from the previous device in a chain. In single device mode the FXI input must be tied LOW if the PAFn bus is operated in direct mode. If the PAFn bus is operated in polled mode the FXI input must be connected to the FXO output of the same device. In expansion mode the FXI of the first device should be tied LOW, when direct mode is selected. FXO (T3) PAFn Bus Expansion Out LVTTL OUTPUT FXO is an output that is used when multi-queue devices are connected in expansion mode and Polled PAFn bus operation has been selected . FXO of device ‘N’ connects directly to FXI of device ‘N+1’. This pin pulses when device N has placed its final (4th) quadrant on to the PAFn bus with respect to WCLK. This pulse (token) is then passed on to the next device in the chain ‘N+1’ and on the next WCLK rising edge the first quadrant of device N+1 will be loaded on to the PAFn bus. This continues through the chain and FXO of the last device is then looped back to FXI of the first device. The FSYNC output of each device in the chain provides synchronization to the user of this looping event. ID[2:0](1) ID2-C9 ID1-A10 ID0-B10 Device ID Pins IOSEL (C8) IO Select LVTTL INPUT This pin is used to select either HSTL or 2.5V LVTTL operation for the I/O. If HSTL or eHSTL I/O are required then IOSEL should be tied HIGH. If LVTTL I/O are required then it should be tied LOW. IW(1) (L15) Input Width LVTTL INPUT This pin is used in conjunction with OW and BM to setup the input and output bus widths to be a combination of x9, x18 or x36, (providing that one port is x36). MAST(1) (K15) Master Device HSTL-LVTTL The state of this input at Master Reset determines whether a given device (within a chain of devices), is the INPUT Master device or a Slave. If this pin is HIGH, the device is the master if it is LOW then it is a Slave. The master device is the first to take control of all outputs after a master reset, all slave devices go to HighImpedance, preventing bus contention. If a multi-queue device is being used in single device mode, this pin must be set HIGH. MRS (T9) Master Reset HSTL-LVTTL A master reset is performed by taking MRS from HIGH to LOW, to HIGH. Device programming is required INPUT after master reset. NULL-Q (J2) Null Queue Select HSTL-LVTTL This pin is used on the read port when a Null-Q is required, it is used in conjunction with the RDADD INPUT and RADEN address bus to address the Null-Q. HSTL-LVTTL For the 32Q multi-queue device the WRADD and RDADD address busses are 8 bits wide. When a queue INPUT selection takes place the 3 MSb’s of this 8 bit address bus are used to address the specific device (the 5 LSb’s are used to address the queue within that device). During write/read operations the 3 MSb’s of the address are compared to the device ID pins. The first device in a chain of multi-queue’s (connected in expansion mode), may be setup as ‘000’, the second as ‘001’ and so on through to device 8 which is ‘111’, however the ID does not have to match the device order. In single device mode these pins should be setup as ‘000’ and the 3 MSb’s of the WRADD and RDADD address busses should be tied LOW. The ID[2:0] inputs setup a respective devices ID during master reset. These ID pins must not toggle during any device operation. Note, the device selected as the ‘Master’ does not have to have the ID of ‘000’. 8 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES PIN DESCRIPTIONS (CONTINUED) Symbol & Pin No. OE (M14) Name I/O TYPE Description Output Enable HSTL-LVTTL The Output enable signal is an Asynchronous signal used to provide three-state control of the multi-queue INPUT data output bus, Qout. If a device has been configured as a “Master” device, the Qout data outputs will be in a Low Impedance condition if the OE input is LOW. If OE is HIGH then the Qout data outputs will be in High Impedance. If a device is configured a “Slave” device, then the Qout data outputs will always be in High Impedance until that device has been selected on the Read Port, at which point OE provides threestate of that respective device. OV (P9) Output Valid Flag HSTL-LVTTL This output flag provides output valid status for the data word present on the multi-queue flow-control device OUTPUT data output port, Qout. This flag is therefore, 2-stage delayed to match the data output path delay. That is, there is a 2 RCLK cycle delay from the time a given queue is selected for reads, to the time the OV flag represents the data in that respective queue. When a selected queue on the read port is read to empty, the OV flag will go HIGH, indicating that data on the output bus is not valid. The OV flag also has High-Impedance capability, required when multiple devices are used and the OV flags are tied together. OW(1) (L16) Output Width PAE (P10) Programmable Almost-Empty Flag PAEn/PRn (PAE7-P11 PAE6-P12 PAE5-R12 PAE4-T12 PAE3-P13 PAE2-R13 PAE1-T13 PAE0-T14) Programmable HSTL-LVTTL On the 32Q device the PAEn/PRn bus is 8 bits wide. During a Master Reset this bus is setup for either Almost-Empty OUTPUT Almost Empty mode or Packet mode. This output bus provides PAE/PRn status of 8 queues (1 quadrant), Flag Bus/Packet within a selected device, having a total of 4 quadrants. During Queue read/write operations these outputs ReadyFlag Bus provide programmable empty flag status or packet ready status, in either direct or polled mode. The mode of flag operation is determined during master reset via the state of the FM input. This flag bus is capable of High-Impedance state, this is important during expansion of multi-queue devices. During direct operation the PAEn/PRn bus is updated to show the PAE/PR status of a quadrant of queues within a selected device. Selection is made using RCLK, ESTR and RDADD. During Polled operation the PAEn/PRn bus is loaded with the PAE/PRn status of multi-queue flow-control quadrants sequentially based on the rising edge of RCLK. PAE or PR operation is determined by the state of PKT during master reset. PAF (R8) Programmable HSTL-LVTTL This pin provides the Almost-Full flag status for the Queue that has been selected on the input port for Almost-Full Flag OUTPUT write operations, (selected via WCLK, WRADD and WADEN). This pin is LOW when the selected Queue is almost-full. This flag output may be duplicated on one of the PAFn bus lines. This flag is synchronized to WCLK. PAFn (PAF7-P7 PAF6-P6 PAF5-R6 PAF4-R7 PAF3-P5 PAF2-R5 PAF1-T5 PAF0-T4) Programmable HSTL-LVTTL On the 32Q device the PAFn bus is 8 bits wide. At any one time this output bus provides PAF status Almost-Full Flag OUTPUT of 8 queues (1 quadrant), within a selected device, having a total of 4 quadrants. During Queue read/ Bus write operations these outputs provide programmable full flag status, in either direct or polled mode. The mode of flag operation is determined during master reset via the state of the FM input. This flag bus is capable of High-Impedance state, this is important during expansion of multi-queue devices. During direct operation the PAFn bus is updated to show the PAF status of a quadrant of queues within a selected device. Selection is made using WCLK, FSTR, WRADD and WADEN. During Polled operation the PAFn bus is loaded with the PAF status of multi-queue flow-control quadrants sequentially based on the rising edge of WCLK. PD (K1) Power Down HSTL INPUT This input is used to provide additional power savings. When the device I/O is setup for HSTL/eHSTL mode a HIGH on the PD input disables the data inputs on the write port only, providing significant power savings. In LVTTL mode this pin has no operation PKT(1) (J14) Packet Mode LVTTL INPUT The state of this pin during a Master Reset will determine whether the part is operating in Packet mode providing both a Packet Ready (PR) output and a Programmable Almost Empty (PAE) discrete output, or standard mode, providing a (PAE) output only. If this pin is HIGH during Master Reset the part will operate in packet mode, if it is LOW then almost empty mode. If packet mode has been selected the read port flag bus becomes packet ready flag bus, PRn and the discrete packet ready flag, PR is functional. If almost empty operation has been selected then the flag bus provides almost empty status, PAEn and LVTTL INPUT This pin is setup during Master Reset and must not toggle during any device operation. This pin is used in conjunction with IW and BM to setup the data input and output bus widths to be a combination of x9, x18 or x36, (providing that one port is x36). HSTL-LVTTL This pin provides the Almost-Empty flag status for the Queue that has been selected on the output port OUTPUT for read operations, (selected via RCLK, RDADD and RADEN). This pin is LOW when the selected Queue is almost-empty. This flag output may be duplicated on one of the PAEn bus lines. This flag is synchronized to RCLK. 9 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES PIN DESCRIPTIONS (CONTINUED) Symbol & Pin No. PKT(1) (Continued) (J14) Name I/O TYPE Packet Mode PR (R9) Packet Ready Flag HSTL-LVTTL If packet mode has been selected this flag output provides Packet Ready status of the Queue selected OUTPUT for read operations. During a master reset the state of the PKT input determines whether Packet mode of operation will be used. If Packet mode is selected, then the condition of the PR flag and OV signal are asserted indicates a packet is ready for reading. The user must mark the start of a packet and the end of a packet when writing data into a queue. Using these Start Of Packet (SOP) and End Of Packet (EOP) markers, the multi-queue device sets PR LOW if one or more “complete” packets are available in the queue. A complete packet(s) must be written before the user is allowed to switch queues. PRS (T8) Partial Reset HSTL-LVTTL A Partial Reset can be performed on a single queue selected within the multi-queue device. Before a Partial INPUT Reset can be performed on a queue, that queue must be selected on both the write port and read port 2 clock cycles before the reset is performed. A Partial Reset is then performed by taking PRS LOW for one WCLK cycle and one RCLK cycle. The Partial Reset will only reset the read and write pointers to the first memory location, none of the devices configuration will be changed. LVTTL INPUT Description the discrete almost empty flag, PAE is functional, the PR flag is inactive and should not be connected. Packet Ready utilizes user marked locations to identify start and end of packets being written into the device. Packet Mode can only be selected if both the input port width and output port width are 36 bits. Q[35:0] Data Output Bus HSTL-LVTTL These are the 36 data output pins. Data is read out of the device via these output pins on the rising edge Qout OUTPUT of RCLK provided that REN is LOW, OE is LOW and the Queue is selected. Note, that in Packet Ready (See Pin No. mode Q32-Q35 may be used as packet markers, please see packet ready functional discussion for more table for details) detail. Due to bus matching not all outputs may be used, any unused outputs should not be connected. RADEN (R14) Read Address Enable HSTL-LVTTL The RADEN input is used in conjunction with RCLK and the RDADD address bus to select a queue to INPUT be read from. A queue addressed via the RDADD bus is selected on the rising edge of RCLK provided that RADEN is HIGH. RADEN should be asserted (HIGH) only during a queue change cycle(s). RADEN should not be permanently tied HIGH. RADEN cannot be HIGH for the same RCLK cycle as ESTR. Note, that a read queue selection cannot be made, (RADEN must NOT go active) until programming of the part has been completed and SENO has gone LOW. RCLK (T10) Read Clock HSTL-LVTTL When enabled by REN, the rising edge of RCLK reads data from the selected queue via the output INPUT bus Qout. The queue to be read is selected via the RDADD address bus and a rising edge of RCLK while RADEN is HIGH. A rising edge of RCLK in conjunction with ESTR and RDADD will also select the PAEn/PRn flag quadrant to be placed on the PAEn/PRn bus during direct flag operation. During polled flag operation the PAEn/PRn bus is cycled with respect to RCLK and the ESYNC signal is synchronized to RCLK. The PAE, PR and OV outputs are all synchronized to RCLK. During device expansion the EXO and EXI signals are based on RCLK. RCLK must be continuous and free-running. RDADD Read Address [7:0] Bus (RDADD7-P16 RDADD6-P15 RDADD5-P14 RDADD4-N16 RDADD3-N15 RDADD2-N14 RDADD1-M16 RDADD0-M15) HSTL-LVTTL For the 32Q device the RDADD bus is 8 bits. The RDADD bus is a dual purpose address bus. The first INPUT function of RDADD is to select a Queue to be read from. The least significant 5 bits of the bus, RDADD[4:0] are used to address 1 of 32 possible queues within a multi-queue device. The most significant 3 bits, RDADD[7:5] are used to select 1 of 8 possible multi-queue devices that may be connected in expansion mode. These 3 MSB’s will address a device with the matching ID code. The address present on the RDADD bus will be selected on a rising edge of RCLK provided that RADEN is HIGH, (note, that data can be placed on to the Qout bus, read from the previously selected queue on this RCLK edge). On the next rising RCLK edge after a read queue select, a data word from the previous queue will be placed onto the outputs, Qout, regardless of the REN input. Two RCLK rising edges after read queue select, data will be placed on to the Qout outputs from the newly selected queue, regardless of REN due to the first word fall through effect. The second function of the RDADD bus is to select the quadrant of queues to be loaded on to the PAEn/PRn bus during strobed flag mode. The least significant 2 bits, RDADD[1:0] are used to select the quadrant of a device to be placed on the PAEn bus. The most significant 3 bits, RDADD[7:5] are again used to select 1 of 8 possible multi-queue devices that may be connected in expansion mode. Address bits RDADD[4:2] are don’t care during quadrant selection. The quadrant address present on the RDADD bus will be selected on the rising edge of RCLK provided that ESTR is HIGH, (note, that data can be placed on to the Qout bus, read from the previously selected Queue on this RCLK edge). Please refer to Table 2 for details on RDADD bus. 10 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES PIN DESCRIPTIONS (CONTINUED) Symbol & Pin No. REN (T11) Name I/O TYPE Description Read Enable HSTL-LVTTL The REN input enables read operations from a selected Queue based on a rising edge of RCLK. INPUT A queue to be read from can be selected via RCLK, RADEN and the RDADD address bus regardless of the state of REN. Data from a newly selected queue will be available on the Qout output bus on the second RCLK cycle after queue selection regardless of REN due to the FWFT operation. A read enable is not required to cycle the PAEn/PRn bus (in polled mode) or to select the PAEn quadrant , (in direct mode). SCLK (N3) Serial Clock HSTL-LVTTL If serial programming of the multi-queue device has been selected during master reset, the SCLK input INPUT clocks the serial data through the multi-queue device. Data setup on the SI input is loaded into the device on the rising edge of SCLK provided that SENI is enabled, LOW. When expansion of devices is performed the SCLK of all devices should be connected to the same source. SENI (M2) Serial Input Enable HSTL-LVTTL During serial programming of a multi-queue device, data loaded onto the SI input will be clocked into the INPUT part (via a rising edge of SCLK), provided the SENI input of that device is LOW. If multiple devices are cascaded, the SENI input should be connected to the SENO output of the previous device. So when serial loading of a given device is complete, its SENO output goes LOW, allowing the next device in the chain to be programmed (SENO will follow SENI of a given device once that device is programmed). The SENI input of the master device (or single device), should be controlled by the user. SENO (M1) Serial Output Enable HSTL-LVTTL This output is used to indicate that serial programming or default programming of the multi-queue device OUTPUT has been completed. SENO follows SENI once programming of a device is complete. Therefore, SENO will go LOW after programming provided SENI is LOW, once SENI is taken HIGH again, SENO will also go HIGH. When the SENO output goes LOW, the device is ready to begin normal read/write operations. If multiple devices are cascaded and serial programming of the devices will be used, the SENO output should be connected to the SENI input of the next device in the chain. When serial programming of the first device is complete, SENO will go LOW, thereby taking the SENI input of the next device LOW and so on throughout the chain. When a given device in the chain is fully programmed the SENO output essentially follows the SENI input. The user should monitor the SENO output of the final device in the chain. When this output goes LOW, serial loading of all devices has been completed. SI (L1) Serial In HSTL-LVTTL During serial programming this pin is loaded with the serial data that will configure the multi-queue devices. INPUT Data present on SI will be loaded on a rising edge of SCLK provided that SENI is LOW. In expansion mode the serial data input is loaded into the first device in a chain. When that device is loaded and its SENO has gone LOW, the data present on SI will be directly output to the SO output. The SO pin of the first device connects to the SI pin of the second and so on. The multi-queue device setup registers are shift registers. SO (M3) Serial Out HSTL-LVTTL This output is used in expansion mode and allows serial data to be passed through devices in the chain OUTPUT to complete programming of all devices. The SI of a device connects to SO of the previous device in the chain. The SO of the final device in a chain should not be connected. TCK(2) (A8) JTAG Clock LVTTL INPUT Clock input for JTAG function. One of four terminals required by IEEE Standard 1149.1-1990. Test operations of the device are synchronous to TCK. Data from TMS and TDI are sampled on the rising edge of TCK and outputs change on the falling edge of TCK. If the JTAG function is not used this signal needs to be tied to GND. TDI(2) (B9) JTAG Test Data Input LVTTL INPUT One of four terminals required by IEEE Standard 1149.1-1990. During the JTAG boundary scan operation, test data serially loaded via the TDI on the rising edge of TCK to either the Instruction Register, ID Register and Bypass Register. An internal pull-up resistor forces TDI HIGH if left unconnected. TDO(2) (A9) JTAG Test Data Output LVTTL OUTPUT One of four terminals required by IEEE Standard 1149.1-1990. During the JTAG boundary scan operation, test data serially loaded output via the TDO on the falling edge of TCK from either the Instruction Register, ID Register and Bypass Register. This output is high impedance except when shifting, while in SHIFT-DR and SHIFT-IR controller states. TMS(2) (B8) JTAG Mode Select LVTTL INPUT TMS is a serial input pin. One of four terminals required by IEEE Standard 1149.1-1990. TMS directs the device through its TAP controller states. An internal pull-up resistor forces TMS HIGH if left unconnected. TRST(2) (C7) JTAG Reset LVTTL INPUT TRST is an asynchronous reset pin for the JTAG controller. The JTAG TAP controller does not automatically reset upon power-up, thus it must be reset by either this signal or by setting TMS= HIGH for five TCK cycles. If the TAP controller is not properly reset then the outputs will always be in high-impedance. If the JTAG function is used but the user does not want to use TRST, then TRST can be tied with MRS to ensure 11 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES PIN DESCRIPTIONS (CONTINUED) Symbol & Pin No. TRST(2) (Continued) Name JTAG Reset I/O TYPE LVTTL Description proper queue operation. If the JTAG function is not used then this signal needs to be tied to GND. An internal pull-up resistor forces TRST HIGH if left unconnected. WADEN (P4) Write Address Enable HSTL-LVTTL The WADEN input is used in conjunction with WCLK and the WRADD address bus to select a queue to INPUT be written in to. A queue addressed via the WRADD bus is selected on the rising edge of WCLK provided that WADEN is HIGH. WADEN should be asserted (HIGH) only during a queue change cycle(s). WADEN should not be permanently tied HIGH. WADEN cannot be HIGH for the same WCLK cycle as FSTR. Note, that a write queue selection cannot be made, (WADEN must NOT go active) until programming of the part has been completed and SENO has gone LOW. WCLK (T7) Write Clock HSTL-LVTTL When enabled by WEN, the rising edge of WCLK writes data into the selected Queue via the input INPUT bus, Din. The Queue to be written to is selected via the WRADD address bus and a rising edge of WCLK while WADEN is HIGH. A rising edge of WCLK in conjunction with FSTR and WRADD will also select the flag quadrant to be placed on the PAFn bus during direct flag operation. During polled flag operation the PAFn bus is cycled with respect to WCLK and the FSYNC signal is synchronized to WCLK. The PAFn, PAF and FF outputs are all synchronized to WCLK. During device expansion the FXO and FXI signals are based on WCLK. The WCLK must be continuous and free-running. WEN (T6) Write Enable HSTL-LVTTL The WEN input enables write operations to a selected Queue based on a rising edge of WCLK. A INPUT queue to be written to can be selected via WCLK, WADEN and the WRADD address bus regardless of the state of WEN. Data present on Din can be written to a newly selected queue on the second WCLK cycle after queue selection provided that WEN is LOW. A write enable is not required to cycle the PAFn bus (in polled mode) or to select the PAFn quadrant , (in direct mode). WRADD Write Address [7:0] Bus (WRADD7-T1 WRADD6-R1 WRADD5-R2 WRADD4-P1 WRADD3-P2 WRADD2-P3 WRADD1-N1 WRADD0-N2) HSTL-LVTTL For the 32Q device the WRADD bus is 8 bits. The WRADD bus is a dual purpose address bus. The INPUT first function of WRADD is to select a Queue to be written to. The least significant 5 bits of the bus, WRADD[4:0] are used to address 1 of 32 possible queues within a multi-queue device. The most significant 3 bits, WRADD[7:5] are used to select 1 of 8 possible multi-queue devices that may be connected in expansion mode. These 3 MSB’s will address a device with the matching ID code. The address present on the WRADD bus will be selected on a rising edge of WCLK provided that WADEN is HIGH, (note, that data present on the Din bus can be written into the previously selected queue on this WCLK edge and on the next rising WCLK also, providing that WEN is LOW). Two WCLK rising edges after write queue select, data can be written into the newly selected queue. The second function of the WRADD bus is to select the quadrant of queues to be loaded on to the PAFn bus during strobed flag mode. The least significant 2 bits, WRADD[1:0] are used to select the quadrant of a device to be placed on the PAFn bus. The most significant 3 bits, WRADD[7:5] are again used to select 1 of 8 possible multi-queue devices that may be connected in expansion mode. Address bits WRADD[4:2] are don’t care during quadrant selection. The quadrant address present on the WRADD bus will be selected on the rising edge of WCLK provided that FSTR is HIGH, (note, that data can be written into the previously selected queue on this WCLK edge). Please refer to Table 1 for details on the WRADD bus. VCC (See pg. 13) +2.5V Supply Power These are VCC power supply pins and must all be connected to a +2.5V supply rail. VDDQ (See pg. 13) O/P Rail Voltage Power These pins must be tied to the desired output rail voltage. For LVTTL I/O these pins must be connected to +2.5V, for HSTL these pins must be connected to +1.5V and for eHSTL these pins must be connected to +1.8V. GND (See pg. 13) Ground Pin Ground These are Ground pins and must all be connected to the GND supply rail. Vref (K3) Reference Voltage HSTL INPUT This is a Voltage Reference input and must be connected to a voltage level determined from the table "Recommended DC Operating Conditions". The input provides the reference level for HSTL/eHSTL inputs. For LVTTL I/O mode this input should be tied to GND. NOTES: 1. Inputs should not change after Master Reset. 2. These pins are for the JTAG port. Please refer to pages 59-62 and Figures 36-38. 12 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES PIN NUMBER TABLE Symbol Name I/O TYPE Pin Number D[35:0] Din Data Input Bus HSTL-LVTTL D35-J3, D(34-32)-H(3-1), D(31-29)-G(3-1), D(28-26)-F(3-1), D(25-23)-E(3-1), D(22-20)-D(3-1), INPUT D(19-17)-C(3-1), D(16,15)-B(2,1), D(14-12)-A(1-3), D11-B3, D10-A4, D9-B4, D8-C4, D7-A5, D6-B5, D5-C5, D4-A6, D3-B6, D2-C6, D1-A7, D0-B7 Q[35:0] Qout Data Output Bus HSTL-LVTTL Q(35,34)-J(15,16), Q(33-31)-H(14-16), Q(30-28)-G(14-16), Q(27-25)-F(14-16), Q(24-22)-E(14-16), OUTPUT Q(21,20)-D(15,16), Q19-B16, Q(18,17)-C(16,15), Q16-D14, Q(15,14)-A(16,15), Q13-B15, Q12-A14, Q11-B14, Q10-C14, Q9-A13, Q8-B13, Q7-C13, Q6-A12, Q5-B12, Q4-C12, Q3-A11, Q2-B11, Q(1,0)-C(11,10) V CC +2.5V Supply Power D(7-10), E(6,7,10,11), F(5,12), G(4,5,12,13), H(4,13), J(4,13), K(4,5,12,13), L(5,12), M(6,7,10,11), N(7-10) VDDQ O/P Rail Voltage Power D(4-6,11-13), E(4,5,12,13), F(4,13), L(4,13), M(4,5,12,13), N(4-6,11-13) GND Ground Pin Ground E(8-9), F(6-11), G(6-11), H(5-12), J(1,5-12), K(2,6-11,14), L(6-11), M(8-9) 13 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits ABSOLUTE MAXIMUM RATINGS COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES CAPACITANCE (TA = +25°C, f = 1.0MHz) Symbol VTERM Rating Terminal Voltage with respect to GND Commercial –0.5 to +3.6(2) Unit V TSTG Storage Temperature –55 to +125 °C IOUT DC Output Current –50 to +50 mA NOTES: 1. Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability. 2. Compliant with JEDEC JESD8-5. VCC terminal only. Symbol CIN (2,3) COUT(1,2) Parameter(1) Conditions VCC GND Parameter Supply Voltage Supply Voltage 10 pF Output Capacitance VOUT = 0V 15 pF Typ. Max. Unit 2.375 0 2.5 0 2.625 0 V V VIH Input High Voltage LVTTL eHSTL HSTL 1.7 VREF+0.2 VREF+0.2 — — — 3.45 — — V V V VIL Input Low Voltage LVTTL eHSTL HSTL -0.3 — — — — — 0.7 VREF-0.2 VREF-0.2 V V V eHSTL HSTL 0.8 0.68 0.9 0.75 1.0 0.9 V V 0 — 70 °C -40 — 85 °C Voltage Reference Input VREF (HSTL only) TA Operating Temperature Commercial TA Operating Temperature Industrial NOTE: 1. VREF is only required for HSTL or eHSTL inputs. VREF should be tied LOW for LVTTL operation. 14 Unit VIN = 0V NOTES: 1. With output deselected, (OE ≥ VIH). 2. Characterized values, not currently tested. 3. CIN for Vref is 20pF. Min. (3) Input Capacitance RECOMMENDED DC OPERATING CONDITIONS Symbol Max. IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES DC ELECTRICAL CHARACTERISTICS (Commercial: VCC = 2.5V ± 0.125V, TA = 0°C to +70°C;Industrial: VCC = 2.5V ± 0.125V, TA = -40°C to +85°C) Symbol Parameter Min. Max. Unit ILI Input Leakage Current –10 10 µA ILO Output Leakage Current –10 10 µA VDDQ -0.4 VDDQ -0.4 VDDQ -0.4 — — — — — — 0.4V 0.4V 0.4V V V V V V V I/O = LVTTL I/O = HSTL I/O = eHSTL — — — 80 150 150 mA mA mA I/O = LVTTL I/O = HSTL I/O = eHSTL Standby VCC Current in Power Down mode(VCC = 2.5V) I/O = LVTTL I/O = HSTL I/O = eHSTL — — — — — — 25 100 100 — 50 50 mA mA mA mA mA mA Active VDDQ Current (VDDQ = 2.5V LVTTL) (VDDQ = 1.5V HSTL) (VDDQ = 1.8V eHSTL) — — — 10 10 10 mA mA mA VOH (3) Output Logic “1” Voltage, IOH = –8 mA @VDDQ = 2.5V ± 0.125V (LVTTL) IOH = –8 mA @VDDQ = 1.8V ± 0.1V (eHSTL) IOH = –8 mA @VDDQ = 1.5V ± 0.1V (HSTL) IOL = 8 mA @VDDQ = 2.5V ± 0.125V (LVTTL) IOL = 8 mA @VDDQ = 1.8V ± 0.1V (eHSTL) IOL = 8 mA @VDDQ = 1.5V ± 0.1V (HSTL) VOL Output Logic “0” Voltage, ICC1(1,2) Active VCC Current (VCC = 2.5V) ICC2(1) Standby VCC Current (VCC = 2.5V) ICC3(1) IDDQ(1,2) I/O = LVTTL I/O = HSTL I/O = eHSTL NOTES: 1. Both WCLK and RCLK toggling at 20MHz. 2. Data inputs toggling at 10MHz. 3. Total Power consumed: PT = [(VCC x ICC) + (VDDQ x IDDQ)]. 4. Outputs are not 3.3V tolerant. 5. The following inputs should be pulled to GND: WRADD, RDADD, WADEN, FSTR, ESTR, SCLK, SI, EXI, FXI and all Data Inputs. The following inputs should be pulled to VCC: WEN, REN, SENI, PRS, MRS, TDI, TMS and TRST. All other inputs are don't care and should be at a known state. 15 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES HSTL 1.5V AC TEST CONDITIONS AC TEST LOADS VDDQ/2 Input Pulse Levels Input Rise/Fall Times Input Timing Reference Levels Output Reference Levels 0.25 to 1.25V 0.4ns 0.75 VDDQ/2 50Ω Z0 = 50Ω I/O 5998 drw04 NOTE: 1. VDDQ = 1.5V±. Figure 2a. AC Test Load EXTENDED HSTL 1.8V AC TEST CONDITIONS 0.4 to 1.4V 0.4ns 0.9 VDDQ/2 ∆tCD (Typical, ns) Input Pulse Levels Input Rise/Fall Times Input Timing Reference Levels Output Reference Levels 6 5 4 3 2 1 NOTE: 1. VDDQ = 1.8V±. 20 30 50 2.5V LVTTL 2.5V AC TEST CONDITIONS 80 100 Capacitance (pF) 200 5998 drw04a Figure 2b. Lumped Capacitive Load, Typical Derating Input Pulse Levels Input Rise/Fall Times Input Timing Reference Levels Output Reference Levels GND to 2.5V 1ns VCC/2 VDDQ/2 NOTE: 1. For LVTTL VCC = VDDQ. OUTPUT ENABLE & DISABLE TIMING Output Enable Output Disable VIH OE VIL tOE & tOLZ Output Normally LOW Output Normally HIGH VCC/2 tOHZ VCC/2 100mV 100mV VOL VOH 100mV 100mV VCC/2 VCC/2 NOTE: 1. REN is HIGH. 5998 drw04b 16 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES AC ELECTRICAL CHARACTERISTICS (Commercial: VCC = 2.5V ± 0.15V, TA = 0°C to +70°C;Industrial: VCC = 2.5V ± 0.15V, TA = -40°C to +85°C; JEDEC JESD8-A compliant) fS tA tCLK tCLKH tCLKL tDS tDH tENS tENH tRS tRSS tRSR tPRSS tPRSH tOLZ (OE-Qn)(2) tOHZ(2) tOE fC tSCLK tSCKH tSCKL tSDS tSDH tSENS tSENH tSDO tSENO tSDOP tSENOP tPCWQ tPCRQ tAS tAH tWFF tROV tSTS tSTH tQS tQH tWAF tRAE tPAF tPAE Parameter Clock Cycle Frequency (WCLK & RCLK) Data Access Time Clock Cycle Time Clock High Time Clock Low Time Data Setup Time Data Hold Time Enable Setup Time Enable Hold Time Reset Pulse Width Reset Setup Time Reset Recovery Time Partial Reset Setup Partial Reset Hold Output Enable to Output in Low-Impedance Output Enable to Output in High-Impedance Output Enable to Data Output Valid Clock Cycle Frequency (SCLK) Serial Clock Cycle Serial Clock High Serial Clock Low Serial Data In Setup Serial Data In Hold Serial Enable Setup Serial Enable Hold SCLK to Serial Data Out SCLK to Serial Enable Out Serial Data Out Propagation Delay Serial Enable Propagation Delay Programming Complete to Write Queue Selection Programming Complete to Read Queue Selection Address Setup Address Hold Write Clock to Full Flag Read Clock to Output Valid PAE/PAF Strobe Setup PAE/PAF Strobe Hold Queue Setup Queue Hold WCLK to PAF flag RCLK to PAE flag Write Clock to Synchronous Almost-Full Flag Bus Read Clock to Synchronous Almost-Empty Flag Bus Com'l & Ind'l(1) IDT72T51546L6 IDT72T51556L6 Min. Max. Unit — 0.6 5 2.3 2.3 1.5 0.5 1.5 0.5 30 15 10 1.5 0.5 0.6 0.6 0.6 — 100 45 45 20 1.2 20 1.2 — — 1.5 1.5 20 20 1.5 1.0 — — 1.5 0.5 1.5 1.0 0.6 0.6 0.6 0.6 — 0.6 6 2.7 2.7 2.0 0.5 2.0 0.5 30 15 10 2.0 0.5 0.6 0.6 0.6 — 100 45 45 20 1.2 20 1.2 — — 1.5 1.5 20 20 2.5 1.5 — — 2.0 0.5 2.0 0.5 0.6 0.6 0.6 0.6 MHz ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns MHz ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns 200 3.6 — — — — — — — — — — — — 3.6 3.6 3.6 10 — — — — — — — 20 20 3.7 3.7 — — — — 3.6 3.6 — — — — 3.6 3.6 3.6 3.6 166 3.7 — — — — — — — — — — — — 3.7 3.7 3.7 10 — — — — — — — 20 20 3.7 3.7 — — — 3.7 3.7 — — — — 3.7 3.7 3.7 3.7 AD INF VA O R NCE MA TIO N Symbol Commercial IDT72T51546L5 IDT72T51556L5 Min. Max. NOTES: 1. Industrial temperature range product for the 6ns is available as a standard device. All other speed grades available by special order. 2. Values guaranteed by design, not currently tested. 17 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES AC ELECTRICAL CHARACTERISTICS (CONTINUED) (Commercial: VCC = 2.5V ± 0.15V, TA = 0°C to +70°C;Industrial: VCC = 2.5V ± 0.15V, TA = -40°C to +85°C; JEDEC JESD8-A compliant) tERCLK tCLKEN tPAELZ(2) tPAEHZ(2) tPAFLZ(2) tPAFHZ(2) tFFHZ(2) tFFLZ(2) tOVLZ(2) tOVHZ(2) tFSYNC tFXO tESYNC tEXO tPR tSKEW1 tSKEW2 tSKEW3 tSKEW4 tSKEW5 tXIS tXIH Parameter RCLK to Echo RCLK Output RCLK to Echo REN Output RCLK to PAE Flag Bus to Low-Impedance RCLK to PAE Flag Bus to High-Impedance WCLK to PAF Flag Bus to Low-Impedance WCLK to PAF Flag Bus to High-Impedance WCLK to Full Flag to High-Impedance WCLK to Full Flag to Low-Impedance RCLK to Output Valid Flag to Low-Impedance RCLK to Output Valid Flag to High-Impedance WCLK to PAF Bus Sync to Output WCLK to PAF Bus Expansion to Output RCLK to PAE Bus Sync to Output RCLK to PAE Bus Expansion to Output RCLK to Packet Ready Flag SKEW time between RCLK and WCLK for FF and OV SKEW time between RCLK and WCLK for PAF and PAE SKEW time between RCLK and WCLK for PAF[0:7] and PAE[0:7] SKEW time between RCLK and WCLK for PR and OV SKEW time between RCLK and WCLK for OV when in Packet Mode Expansion Input Setup Expansion Input Hold Com'l & Ind'l(1) IDT72T51546L6 IDT72T51556L6 Min. Max. — — 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 4 5 5 5 8 1.0 0.5 — — 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 4.5 6 6 6 10 1.0 0.5 4.0 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 — — — — — — — 4.2 3.7 3.7 3.7 3.7 3.7 3.7 3.7 3.7 3.7 3.7 3.7 3.7 3.7 3.7 — — — — — — — AD INF VA O R NCE MA TIO N Symbol Commercial IDT72T51546L5 IDT72T51556L5 Min. Max. NOTES: 1. Industrial temperature range product for the 6ns is available as a standard device. All other speed grades available by special order. 2. Values guaranteed by design, not currently tested. 18 Unit ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits FUNCTIONAL DESCRIPTION MASTER RESET A Master Reset is performed by toggling the MRS input from HIGH to LOW to HIGH. During a master reset all internal multi-queue device setup and control registers are initialized and require programming either serially by the user via the serial port, or using the default settings. During a master reset the state of the following inputs determine the functionality of the part, these pins should be held HIGH or LOW. PKT – Packet Mode FM – Flag bus Mode IW, OW, BM – Bus Matching options MAST – Master Device ID0, 1, 2 – Device ID DFM – Programming mode, serial or default DF – Offset value for PAE and PAF Once a master reset has taken place, the device must be programmed either serially or via the default method before any read/write operations can begin. See Figure 5, Master Reset for relevant timing. PARTIAL RESET A Partial Reset is a means by which the user can reset both the read and write pointers of a single queue that has been setup within a multi-queue device. Before a partial reset can take place on a queue, the respective queue must be selected on both the read port and write port a minimum of 2 RCLK and 2 WCLK cycles before the PRS goes LOW. The partial reset is then performed by toggling the PRS input from HIGH to LOW to HIGH, maintaining the LOW state for at least one WCLK and one RCLK cycle. Once a partial reset has taken place a minimum of 3 WCLK and 3 RCLK cycles must occur before enabled writes or reads can occur. A Partial Reset only resets the read and write pointers of a given queue, a partial reset will not effect the overall configuration and setup of the multi-queue device and its queues. See Figure 6, Partial Reset for relevant timing. SERIAL PROGRAMMING The multi-queue flow-control device is a fully programmable device, providing the user with flexibility in how queues are configured in terms of the number of queues, depth of each queue and position of the PAF/PAE flags within respective queues. All user programming is done via the serial port after a master reset has taken place. Internally the multi-queue device has setup registers which must be serially loaded, these registers contain values for every queue within the device, such as the depth and PAE/PAF offset values. The IDT72T51546/72T51556 devices are capable of up to 32 queues and therefore contain 32 sets of registers for the setup of each queue. During a Master Reset if the DFM (Default Mode) input is LOW, then the device will require serial programming by the user. It is recommended that the user utilize a ‘C’ program provided by IDT, this program will prompt the user for all information regarding the multi-queue setup. The program will then generate a serial bit stream which should be serially loaded into the device via the serial port. For the IDT72T51546/72T51556 devices the serial programming requires a total number of serially loaded bits per device, (SCLK cycles with SENI enabled), calculated by: 19+(Qx72) where Q is the number of queues the user wishes to setup within the device. Once the master reset is complete and MRS is HIGH, the device can be serially loaded. Data present on the SI (serial in), input is loaded into the serial port on a rising edge of SCLK (serial clock), provided that SENI (serial in enable), is LOW. Once serial programming of the device has been successfully 19 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES completed the device will indicate this via the SENO (serial output enable) going active, LOW. Upon detection of completion of programming, the user should cease all programming and take SENI inactive, HIGH. Note, SENO follows SENI once programming of a device is complete. Therefore, SENO will go LOW after programming provided SENI is LOW, once SENI is taken HIGH again, SENO will also go HIGH. The operation of the SO output is similar, when programming of a given device is complete, the SO output will follow the SI input. If devices are being used in expansion mode the serial ports of devices should be cascaded. The user can load all devices via the serial input port control pins, SI & SENI, of the first device in the chain. Again, the user may utilize the ‘C’ program to generate the serial bit stream, the program prompting the user for the number of devices to be programmed. The SENO and SO (serial out) of the first device should be connected to the SENI and SI inputs of the second device respectively and so on, with the SENO & SO outputs connecting to the SENI & SI inputs of all devices through the chain. All devices in the chain should be connected to a common SCLK. The serial output port of the final device should be monitored by the user. When SENO of the final device goes LOW, this indicates that serial programming of all devices has been successfully completed. Upon detection of completion of programming, the user should cease all programming and take SENI of the first device in the chain inactive, HIGH. As mentioned, the first device in the chain has its serial input port controlled by the user, this is the first device to have its internal registers serially loaded by the serial bit stream. When programming of this device is complete it will take its SENO output LOW and bypass the serial data loaded on the SI input to its SO output. The serial input of the second device in the chain is now loaded with the data from the SO of the first device, while the second device has its SENI input LOW. This process continues through the chain until all devices are programmed and the SENO of the final device goes LOW. Once all serial programming has been successfully completed, normal operations, (queue selections on the read and write ports) may begin. When connected in expansion mode, the IDT72T51546/72T51556 devices require a total number of serially loaded bits per device to complete serial programming, (SCLK cycles with SENI enabled), calculated by: n[19+(Qx72)] where Q is the number of queues the user wishes to setup within the device, where n is the number of devices in the chain. See Figure 7, Serial Port Connection and Figure 8, Serial Programming for connection and timing information. DEFAULT PROGRAMMING During a Master Reset if the DFM (Default Mode) input is HIGH the multiqueue device will be configured for default programming, (serial programming is not permitted). Default programming provides the user with a simpler, however limited means by which to setup the multi-queue flow-control device, rather than using the serial programming method. The default mode will configure a multi-queue device such that the maximum number of queues possible are setup, with all of the parts available memory blocks being allocated equally between the queues. The values of the PAE/PAF offsets is determined by the state of the DF (default) pin during a master reset. For the IDT72T51546/72T51556 devices the default mode will setup 32 queues, each queue being 1024 x36 and 2048 x36 deep respectively. For both devices the value of the PAE/PAF offsets is determined at master reset by the state of the DF input. If DF is LOW then both the PAE & PAF offset will be 8, if HIGH then the value is 128. When configuring the IDT72T51546/72T51556 devices in default mode the user simply has to apply WCLK cycles after a master reset, until SENO goes LOW, this signals that default programming is complete. These clock cycles are required for the device to load its internal setup registers. When a single multiqueue device is used, the completion of device programming is signaled by the IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits SENO output of a device going from HIGH to LOW. Note, that SENI must be held LOW when a device is setup for default programming mode. When multi-queue devices are connected in expansion mode, the SENI of the first device in a chain can be held LOW. The SENO of a device should connect to the SENI of the next device in the chain. The SENO of the final device is used to indicate that default programming of all devices is complete. When the final SENO goes LOW normal operations may begin. Again, all devices will be programmed with their maximum number of queues and the memory divided equally between them. Please refer to Figure 9, Default Programming. COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES selection. The queue selection requires 1 WCLK cycle. All subsequent data writes will be to this queue until another queue is selected. Standard mode operation is defined as individual words will be written to the device as opposed to Packet Mode where complete packets may be written. The write port is designed such that 100% bus utilization can be obtained. This means that data can be written into the device on every WCLK rising edge including the cycle that a new queue is being addressed. Changing queues requires a minimum of 3 WCLK cycles on the write port (see Figure 10, Write Queue Select, Write Operation and Full flag Operation). WADEN goes high signaling a change of queue (clock cycle “A”). The address on WRADD at that time determines the next queue. Data presented during that cycle (“A”) and the next cycle (“B” and “C”), will be written to the active (old) queue, provided WEN is active LOW. If WEN is HIGH (inactive) for these 3 clock cycles, data will not be written in to the previous queue. The write port discrete full flag will update to show the full status of the newly selected queue (QX) at this last cycle’s rising edge (“C”). Data present on the data input bus (Din), can be written into the newly selected queue (QX) on the rising edge of WCLK on the third cycle (“D”) following a change of queue, provided WEN is LOW and the new queue is not full. If the newly selected queue is full at the point of its selection, any writes to that queue will be prevented. Data cannot be written into a full queue. Refer to Figure 10, Write Queue Select, Write Operation and Full flag Operation, Figure 11, Write Operations & First Word Fall Through for timing diagrams and Figure 12, Full Flag Timing in Expansion Mode for timing diagrams. READING AND WRITING TO THE IDT MULTI-QUEUE FLOW-CONTROL DEVICE The IDT72T51546/72T51556 multi-queue flow-control devices can be configured in two distinct modes, namely Standard Mode and Packet Mode. STANDARD MODE OPERATION (PKT = LOW ON MASTER RESET) WRITE QUEUE SELECTION AND WRITE OPERATION (STANDARD MODE) The IDT72T51546/72T51556 multi-queue flow-control devices can be configured up to a maximum of 32 queues into which data can be written via a common write port using the data inputs (Din), write clock (WCLK) and write enable (WEN). The queue to be written is selected by the address present on the write address bus (WRADD) during a rising edge on WCLK while write address enable (WADEN) is HIGH. The state of WEN does not impact the queue TABLE 1 — WRITE ADDRESS BUS, WRADD[7:0] Operation WCLK WADEN FSTR Write Queue Select 1 PAFn Quadrant Select 0 0 WRADD[7:0] 7 6 5 4 3 2 1 0 Device Select Write Queue Address (Compared to (5 bits = 32 Queues) ID0,1,2) 1 Quadrant Address 00 01 10 11 7 6 5 Device Select (Compared to ID0,1,2) 4 3 2 X X 1 0 X Quadrant Address Queue Status on PAFn Bus Q0 : Q7 → PAF0 : PAF7 Q8 : Q15 → PAF0 : PAF7 Q16 : Q23 → PAF0 : PAF7 Q24 : Q31 → PAF0 : PAF7 5998 drw05 20 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits READ QUEUE SELECTION AND READ OPERATION (STANDARD MODE) The IDT72T51546/72T51556 multi-queue flow-control devices can be configured up to a maximum of 32 queues which data can be read via a common read port using the data outputs (Qout), read clock (RCLK) and read enable (REN). An output enable, OE control pin is also provided to allow HighImpedance selection of the Qout data outputs. The multi-queue device read port operates in a mode similar to “First Word Fall Through” on a SuperSync IDT FIFO, but with the added feature of data output pipelining (see Figure 11, Write Operations & First Word Fall Through). The queue to be read is selected by the address presented on the read address bus (RDADD) during a rising edge on RCLK while read address enable (RADEN) is HIGH. The state of REN does not impact the queue selection. The queue selection requires 1 RCLK cycles. All subsequent data reads will be from this queue until another queue is selected. Standard mode operation is defined as individual words will be read from the device as opposed to Packet Mode where complete packets may be read. The read port is designed such that 100% bus utilization can be obtained. This means that data can be read out of the device on every RCLK rising edge including the cycle that a new queue is being addressed. Changing queues requires a minimum of three RCLK cycles on the read port (see Figure 13, Read Queue Select, Read Operation). RADEN goes high signaling a change of queue (clock cycle “D”). The address on RDADD at that time determines the next queue. Data presented during that cycle (“D”) will be read at “D” (+ tA), and the next cycle (“E”), can continue to be read from the active (old) queue (QP), provided REN is active LOW. If REN is HIGH (inactive) for these two clock cycles, data will not be read from the previous queue. The next COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES cycle’s rising edge (“F”), the read port discrete empty flag will update to show the empty status of the newly selected queue (QF). The internal pipeline is also loaded at this time (“F”) with the last word from the previous (old) queue (QF) as well as the next word from the new queue (QF). Both of these words will fall through to the output register (provided the OE is asserted) consecutively (cycles “F” and “G” respectively) following the selection of the new queue regardless of the state of REN, unless the new queue (QF) is empty. If the newly selected queue is empty, any reads from that queue will be prevented. Data cannot be read from an empty queue. The last word in the data output register (from the previous queue), will remain on the data bus, but the output valid flag, OV will go HIGH, to indicate that the data present is no longer valid. This pipelining effect provides the user with 100% bus utilization, and brings about the possibility that a “NULL” queue may be required within a multi-queue device. Null queue operation is discussed in the next section. Remember that OE allows the user to place the data output bus (Qout) into High-Impedance and the data can be read in to the output register regardless of OE. Refer to Table 2, for Read Address Bus arrangement. Also, refer to Figures 13, 15, and 16 for read queue selection and read port operation timing diagrams. PACKET MODE OPERATION (PKT = HIGH on Master Reset) The Packet mode operation provides the capability where, user defined packets or frames can be written to the device as opposed to Standard mode where individual words are written. For clarification, in Packet Mode, a packet can be written to the device with the starting location designated as Transmit Start of Packet (TSOP) and the ending location designated as Transmit End of Packet (TEOP). In conjunction, a packet read from the device will be designated as TABLE 2 — READ ADDRESS BUS, RDADD[7:0] Operation RCLK RADEN ESTR Null-Q Read Queue Select 1 0 0 PAEn/PRn Quadrant Select 0 1 0 Null Queue Select 1 0 1 RDADD[7:0] 7 6 5 4 3 2 1 0 Device Select Read Queue Address (Compared to (5 bits = 32 Queues) ID0,1,2) Quadrant Address 00 01 10 11 7 6 5 Device Select (Compared to ID0,1,2) 4 3 2 X X X 1 0 Quadrant Address 7 6 5 4 3 2 1 0 X X X X X X X X Queue Status on PAEn/PRn Bus Q0 : Q7 → PAE0 : PAE7 Q8 : Q15 → PAE0 : PAE7 Q16 : Q23 → PAE0 : PAE7 Q24 : Q31 → PAE0 : PAE7 5998 drw06 21 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits Receive Start of Packet (RSOP) and a Receive End of Packet (REOP). The minimum size for a packet is four words (SOP, two words of data and EOP). The almost empty flag bus becomes the “Packet Ready” PR flag bus when the device is configured for packet mode. Valid packets are indicated when both PR and OV are asserted. WRITE QUEUE SELECTION AND WRITE OPERATION (PACKET MODE) It is required that a full packet be written to a queue before moving to a different queue. The device requires three cycles to change queues. Packet mode, has 2 restrictions: <1> An extra word (or filler word) is required to be written after each packet on the cycle following the queue change to ensure the RSOP in the old queue is not read out on a queue change because of the first word fall through. <2> No SOP/EOP is allowed to read/written at cycle (“D” or “K”) the second cycle after a queue change. In this mode, the write port may not obtain 100% bus utilization. Changing queues requires a minimum of 3 WCLK cycles on the write port (see Figure 17, Writing in Packet Mode during a Queue Change). WADEN goes high signaling a change of queue (clock cycle “B” or “I”). The address on WRADD at the rising edge of WCLK determines the next queue. Data presented on Din during that cycle (“B” or “I”) and the next cycle (“C” or “J”) can continue to be written to the active (old) queue (QA or QB respectively), provided WEN is LOW (active). If WEN is HIGH (inactive) for these two clock cycles (H), data will not be written in to the previous queue (QA). The second cycle following a request for queue change (“D” or “K”) will require a “filler” word to be written to the device. This can be done by clocking the TEOP twice or by writing a “filler” word. In packet mode, the multi-queue is designed under the 2 restrictions listed previously. Note, an erroneous Packet Ready flag may occur if the EOP or SOP marker shows up at the second cycle after a queue change. To prevent an erroneous Packet Ready flag from occurring a filler word should be written into the old queue at the last clock cycle of writing. It is important to know that no SOP or EOP may be written into the device during this cycle (“D” or “K”). The write port discrete full flag will update to show the full status of the newly selected queue (QB) at this last cycle’s rising edge (“D” or “K”). Data values presented on the data input bus (Din), can be written into the newly selected queue (QX) on the rising edge of WCLK on the third cycle (“E”) following a request for change of queue, provided WEN is LOW (active) and the new queue is not full. If a selected queue is full (FF is LOW), then writes to that queue will be prevented. Note, data cannot be written into a full queue. Refer to Figure 17, Writing in Packet Mode during a Queue Change and Figure 19, Data Input (Transit) Packet Mode of Operation for timing diagrams. READ QUEUE SELECTION AND READ OPERATION (PACKET MODE) In packet Mode it is required that a full packet is read from a queue before moving to a different queue. The device requires three cycles to change queues. In Packet Mode, there are 2 restrictions <1> An extra word (or filler word) should have been inserted into the data stream after each packet to insure the RSOP in the old queue is not read out on a queue change because of the first word fall through and this word should be discarded. <2> No EOP/SOP is allowed to be read/written at cycle (“D” or “K”) the second cycle after a queue change). In this mode, the read port may not obtain 100% bus utilization. Changing queues requires a minimum of 3 RCLK cycles on the read port (see Figure 18, Reading in Packet Mode during a Queue Change). RADEN goes high signaling a change of queue (clock cycle “B” or “I”). The address on RDADD at the rising edge of RCLK determines the queue. As illustrated in Figure 18 during cycle (“B” or “I”), and the next cycle (“C” or “J”) data can continue to be read from the active (old) queue (QA or QB respectively), provided both REN and OE are LOW (active) simultaneously with changing queues. REOP for packet located in queue (QA) must be read on or before a queue change COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES request is made (“C” or “J”). If REN is HIGH (inactive) for these two clock cycles, data will not be read from the previous queue (QA). In applications where the multi-queue flow-control device is connected to a shared bus, an output enable, OE control pin is also provided to allow High-Impedance selection of the data outputs (Qout). With reference to Figure 18 when changing queues, a packet marker (SOP or EOP) should not be read on cycle (“E” or “L”). Reading a SOP or EOP should not occur during the cycles required for a queue change. It is also recommended that a queue change should not occur once the reading of the packet has commenced, The EOP marker of the packet prior to a queue change should be read on or before the queue change. If the EOP word is read before a queue change, REN can be pulled high to disable further reads. When the queue change is initiated, the filler word written into the current queue after the EOP word will fall through followed by and the first word from the new queue. Refer to Figure 18, Reading in Packet Mode during a Queue Change as well as Figures 13, 15, and 16 for timing diagrams and Table 2, for Read Address bus arrangement. Note, the almost empty flag bus becomes the “Packet Ready” flag bus when the device is configured for packet ready mode. . PACKET READY FLAG The 36-bit multi-queue flow-control device provides the user with a Packet Ready feature. During a Master Reset the logic “1” (HIGH) on the PKT input signal (packet mode select), configures the device in packet mode. The PR discrete flag, provides a packet ready status of the active queue selected on the read port. A packet ready status is individually maintained on all queues; however only the queue selected on the read port has its packet ready status indicated on the PR output flag. A packet is available on the output for reading when both PR and OV are asserted LOW. If less than a full packet is available, the PR flag will be HIGH (packet not ready). In packet mode, no words can be read from a queue until a complete packet has been written into that queue, regardless of REN. When packet mode is selected the Programmable Almost Empty bus, PAEn, becomes the Packet Ready bus, PRn. When configured in Direct Bus (FM = LOW during a master reset), the PRn bus provides packet ready status in 8 queue increments. The PRn bus supports either Polled or Direct modes of operation. The PRn mode of operation is configured through the Flag Mode (FM) bit during a Master Reset. When the multi-queue is configured for packet mode operation, the device must also be configured for 36 bit write data bus and 36 bit read data bus. The two most significant bits of the 36-bit data bus are used as “packet markers”. On the write port these are bits D34 (Transmit Start of Packet,) D35 (Transmit End of Packet) and on the read port Q34, Q35. All four bits are monitored by the packet control logic as data is written into and read out from the queues. The packet ready status for individual queues is then determined by the packet ready logic. On the write port D34 is used to “mark” the first word being written into the selected queue as the “Transmit Start of Packet”, TSOP. To further clarify, when the user requires a word being written to be marked as the start of a packet, the TSOP input (D34) must be HIGH for the same WCLK rising edge as the word that is written. The TSOP marker is stored in the queue along with the data it was written in until the word is read out of the queue via the read port. On the write port D35 is used to “mark” the last word of the packet currently being written into the selected queue as the “Transmit End of Packet” TEOP. When the user requires a word being written to be marked as the end of a packet, the TEOP input must be HIGH for the same WCLK rising edge as the word that is written in. The TEOP marker is stored in the queue along with the data it was written in until the word is read out of the queue via the read port. The packet ready logic monitors all start and end of packet markers both as they enter respective queues via the write port and as they exit queues via the 22 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES BYTE D TMOD1 (D33) RMOD1 (Q33) 0 0 1 1 BYTE C TMOD2 (D32) RMOD2 (Q32) 0 1 0 1 D0/Q0 D7/Q7 D15/Q15 D23/Q23 D31/Q31 MOD 2 D32/Q32 D34/Q34 SOP MOD 1 D33/Q33 D35/Q35 EOP TABLE 5 — PACKET MODE VALID BYTE BYTE B BYTE A VALID BYTES A, B, C, D A A, B A, B, C 5998 drw07 NOTE: Packet Mode is only available when the Input Port and Output Port are 36 bits wide. of packet. This is a useful feature when due to latencies within the system, monitoring the REOP marker alone does not prevent “over reading” of the data from the queue selected. For example, an AEOP marker set 4 writes before the TEOP marker provides the device connected to the read port with and “almost end of packet” indication 4 cycles before the end of packet. The AEOP can be set any number of words before the end of packet determined by user requirements or latencies involved in the system. See Figure 18, Reading in Packet Mode during a Queue Change, Figure 19, Data Input (Transmit) Packet Mode of Operation and Figure 20, Data Output (Receive) Packet Mode of Operation. read port. The multi-queue internal logic increments and decrements a packet counter, which is provided for each queue. The functionality of the packet ready logic provides status as to whether at least one full packet of data is available within the selected queue. A partial packet in a queue is regarded as a packet not ready and PR (active LOW) will be HIGH. In Packet mode, no words can be read from a queue until at least one complete packet has been written into the queue, regardless of REN. For example, if a TSOP has been written and some number of words later a TEOP is written a full packet of data is deemed to be available, and the PR flag and OV will go active LOW. Consequently if reads begin from a queue that has only one complete packet and the RSOP is detected on the output port as data is being read out, PR will go inactive HIGH. OV will remain LOW indicating there is still valid data being read out of that queue until the REOP is read. The user may proceed with the reading operation until the current packet has been read out and no further complete packets are available. If during that time another complete packet has been written into the queue and the PR flag will again gone active, then reads from the new packet may follow after the current packet has been completely read out. The packet counters therefore look for start of packet markers followed by end of packet markers and regard data in between the TSOP and TEOP as a full packet of data. The packet monitoring has no limitation as to how many packets are written into a queue, the only constraint is the depth of the queue. Note, there is a minimum allowable packet size of four words, inclusive of the TSOP marker and TEOP marker. The packet logic does expect a TSOP marker to be followed by a TEOP marker. If a second TSOP marker is written after a first, it is ignored and the logic regards data between the first TSOP and the first subsequent TEOP as the full packet. The same is true for TEOP; a second consecutive TEOP mark is ignored. On the read side the user should regard a packet as being between the first RSOP and the first subsequent REOP and disregard consecutive RSOP markers and/or REOP markers. This is why a TEOP may be written twice, using the second TEOP as the “filler” word. As an example, the user may also wish to implement the use of an “Almost End of Packet” (AEOP) marker. For example, the AEOP can be assigned to data input bit D33. The purpose of this AEOP marker is to provide an indicator that the end of packet is a fixed (known) number of reads away from the end PACKET MODE – MODULO OPERATION The internal packet ready control logic performs no operation on these modulo bits, they are only informational bits that are passed through with the respective data byte(s). When utilizing the multi-queue flow-control device in packet mode, the user may also want to consider the implementation of “Modulo” operation or “valid byte marking”. Modulo operation may be useful when the packets being transferred through a queue are in a specific byte arrangement even though the data bus width is 36 bits. In Modulo operation the user can concatenate bytes to form a specific data string through the multi-queue device. A possible scenario is where a limited number of bytes are extracted from the packet for either analysis or filtered for security protection. This will only occur when the first 36 bit word of a packet is written in and the last 36 bit word of packet is written in. The modulo operation is a means by which the user can mark and identify specific data within the Queue. On the write port data input bits, D32 (transmit modulo bit 2, TMOD2) and D33 (transmit modulo bit 1, TMOD1) can be used as data markers. An example of this could be to use D32 and D33 to code which bytes of a word are part of the packet that is also being marked as the “Start of Marker” or “End of Marker”. Conversely on the read port when reading out these marked words, data outputs Q32 (receive modulo bit 2, RMOD2) and Q33 (receive modulo bit 1, RMOD1) will pass on the byte validity information for that word. Refer to Table 5 for one example of how the modulo bits may be setup and used. See Figure 19, Data Input (Transmit) Packet Mode of Operation and Figure 20, Data Output (Receive) Packet Mode of Operation. 23 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits NULL QUEUE OPERATION (OF THE READ PORT) Pipelining of data to the output port enables the device to provide 100% bus utilization in standard mode. Data can be read out of the multi-queue flow-control device on every RCLK cycle regardless of queue switches or other operations. The device architecture is such that the pipeline is constantly filled with the next words in a selected queue to be read out, again providing 100% bus utilization. This type of architecture does assume that the user is constantly switching queues such that during a queue switch, the last data word required from the previous queue will fall through the pipeline to the output. Note, that if reads cease at the empty boundary of a queue, then the last word will automatically flow through the pipeline to the output. The Null Q operation is achieved by setting the Null Q signal HIGH during a queue select. Note that the read address bus RDADD[7:0] is a don't care. The Null Queue is a separate queue within the device and thus the maximum number of queues and memory is always available regardless of whether or not the Null queue is used. Also note that in expansion mode a user may want to use a dedicated null queue for each device. A null queue can be selected when no further reads are required from a previously selected queue. Changing to a null queue will continue to propagate data in the pipeline to the previous queue's output. The Null Q can remain selected until a data becomes available in another queue for reading. The Null-Q can be utilized in either standard or packet mode. Note: If the user switches the read port to the null queue, this queue is seen as and treated as an empty queue, therefore after switching to the null queue the last word from the previous queue will remain in the output register and the OV flag will go HIGH, indicating data is not valid. The Null queue operation only has significance to the read port of the multiqueue, it is a means to force data through the pipeline to the output. Null Q selection and operation has no meaning on the write port of the device. Also, refer to Figure 21, Read Operation and Null Queue Select for diagram. PAFn FLAG BUS OPERATION The IDT72T51546/72T51556 multi-queue flow-control device can be configured for up to 32 queues, each queue having its own almost full status. An active queue has its flag status output to the discrete flags, FF and PAF, on the write port. Queues that are not selected for a write operation can have their PAF status monitored via the PAFn bus. The PAFn flag bus is 8 bits wide, so that 8 queues at a time can have their status output to the bus. If 9 or more queues are setup within a device then there are 2 methods by which the device can share the bus between queues, “Direct” mode and “Polled” mode depending on the state of the FM (Flag Mode) input during a Master Reset. If 8 or less queues are setup within a device then each will have its own dedicated output from the bus. If 8 or less queues are setup in single device mode, it is recommended to configure the PAFn bus to polled mode as it does not require using the write address (WRADD). EXPANDING UP TO 256 QUEUES OR PROVIDING DEEPER QUEUES Expansion can take place using either the standard mode or the packet mode. In the 32 queue multi-queue device, the WRADD address bus is 8 bits wide. The 5 Least Significant bits (LSbs) are used to address one of the 32 available queues within a single multi-queue device. The 3 Most Significant bits (MSbs) are used when a device is connected in expansion mode with up to 8 devices connected in width expansion, each device having its own 3-bit address. When logically expanded with multiple parts, each device is statically setup with a unique chip ID code on the ID pins, ID0, ID1, and ID2. A device is selected when the 3 Most Significant bits of the WRADD address bus matches a 3-bit ID code. The maximum logical expansion is 256 queues (32 queues x 8 devices) or a minimum of 8 queues (1 queue per device x 8 devices), each of the maximum size of the individual memory device. COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES Note: The WRADD bus is also used in conjunction with FSTR (almost full flag bus strobe), to address the almost full flag bus during direct mode of operation. Refer to Table 1, for Write Address bus arrangement. Also, refer to Figure 12, Full Flag Timing Expansion Mode, Figure 14, Output Valid Flag Timing (In Expansion Mode), and Figure 35, Multi-Queue Expansion Diagram, for timing diagrams. BUS MATCHING OPERATION Bus Matching operation between the input port and output port is available. During a master reset of the multi-queue the state of the three setup pins, BM (Bus Matching), IW (Input Width) and OW (Output Width) determine the input and output port bus widths as per the selections shown in Table 3, “Bus Matching Set-Up”. 9 bit bytes, 18 bit words and 36 bit long words can be written into and read from the Queues provided that at least one of the ports is setup for x36 operation. When writing to or reading from the multi-queue in a bus matching mode, the device orders data in a “Little Endian” format. See Figure 4, Bus Matching Byte Arrangement for details. The Full flag and Almost Full flag operation is always based on writes and reads of data widths determined by the write port width. For example, if the input port is x36 and the output port is x9, then four data reads from a full queue will be required to cause the full flag to go HIGH (queue not full). Conversely, the Output Valid flag and Almost Empty flag operations are always based on writes and reads of data widths determined by the read port. For example, if the input port is x18 and the output port is x36, two write operations will be required to cause the output valid flag of an empty queue to go LOW, output valid (queue is not empty). Note, that the input port serves all queues within a device, as does the output port, therefore the input bus width to all queues is equal (determined by the input port size) and the output bus width from all queues is equal (determined by the output port size). TABLE 3 — BUS-MATCHING SET-UP BM IW x36 DEVICE OW Write Port Read Port 0 1 1 1 1 X 0 0 1 1 X 0 1 0 1 x36 x36 x36 x18 x9 x36 x18 x9 x36 x36 FULL FLAG OPERATION The multi-queue flow-control device provides a single Full Flag output, FF. The FF flag output provides a full status of the queue currently selected on the write port for write operations. Internally the multi-queue flow-control device monitors and maintains a status of the full condition of all queues within it, however only the queue that is selected for write operations has its full status output to the FF flag. This dedicated flag is often referred to as the “active queue full flag”. When queue switches are being made on the write port, the FF flag output will switch to the new queue and provide the user with the new queue status, on the cycle after a new queue selection is made. The user then has a full status for the new queue one cycle ahead of the WCLK rising edge that data can be written into the new queue. That is, a new queue can be selected on the write port via the WRADD bus, WADEN enable and a rising edge of WCLK. On the second rising edge of WCLK, the FF flag output will show the full status of the newly selected queue. On the third rising edge of WCLK following the queue selection, data can be written into the newly selected queue provided that data and enable setup & hold times are met. 24 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits Note, the FF flag will provide status of a newly selected queue two WCLK cycle after queue selection, which is one cycle before data can be written to that queue. This prevents the user from writing data to a queue that is full, (assuming that a queue switch has been made to a queue that is actually full). The FF flag is synchronous to the WCLK and all transitions of the FF flag occur based on a rising edge of WCLK. Internally the multi-queue device monitors and keeps a record of the full status for all queues. It is possible that the status of a FF flag maybe changing internally even though that flag is not the active queue flag (selected on the write port). A queue selected on the read port may experience a change of its internal full flag status based on read operations. See Figure 10, Write Queue Select, Write Operation and Full Flag Operation and Figure 12, Full Flag Timing in Expansion Mode for timing information. COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES When a queue selection is made the first data from that queue will appear on the Qout data outputs 3 RCLK cycles later, the OV will change state to indicate validity of the data from the newly selected queue on this 3rd RCLK cycle also. The previous cycles will continue to output data from the previous queue and the OV flag will indicate the status of those outputs. Again, the OV flag always indicates status for the data currently present on the output register. The OV flag is synchronous to the RCLK and all transitions of the OV flag occur based on a rising edge of RCLK. Internally the multi-queue device monitors and keeps a record of the output valid (empty) status for all queues. It is possible that the status of an OV flag may be changing internally even though that respective flag is not the active queue flag (selected on the read port). A queue selected on the write port may experience a change of its internal OV flag status based on write operations, that is, data may be written into that queue causing it to become “not empty”. See Figure 13, Read Queue Select, Read Operation and Figure 14, Output Valid Flag Timing for details of the timing. EXPANSION MODE - FULL FLAG OPERATION When multi-queue devices are connected in Expansion mode the FF flags of all devices should be connected together, such that a system controller monitoring and managing the multi-queue devices write port only looks at a single FF flag (as opposed to a discrete FF flag for each device). This FF flag is only pertinent to the queue being selected for write operations at that time. Remember, that when in expansion mode only one multi-queue device can be written to at any moment in time, thus the FF flag provides status of the active queue on the write port. This connection of flag outputs to create a single flag requires that the FF flag output have a High-Impedance capability, such that when a queue selection is made only a single device drives the FF flag bus and all other FF flag outputs connected to the FF flag bus are placed into High-Impedance. The user does not have to select this High-Impedance state, a given multi-queue flow-control device will automatically place its FF flag output into High-Impedance when none of its queues are selected for write operations. When queues within a single device are selected for write operations, the FF flag output of that device will maintain control of the FF flag bus. Its FF flag will simply update between queue switches to show the respective queue full status. The multi-queue device places its FF flag output into High-Impedance based on the 3 bit ID code found in the 3 most significant bits of the write queue address bus, WRADD. If the 3 most significant bits of WRADD match the 3 bit ID code setup on the static inputs, ID0, ID1 and ID2 then the FF flag output of the respective device will be in a Low-Impedance state. If they do not match, then the FF flag output of the respective device will be in a High-Impedance state. See Figure 12, Full Flag Timing in Expansion Mode for details of flag operation, including when more than one device is connected in expansion. EXPANSION MODE – OUTPUT VALID FLAG OPERATION When multi-queue devices are connected in Expansion mode, the OV flags of all devices should be connected together, such that a system controller monitoring and managing the multi-queue devices read port only looks at a single OV flag (as opposed to a discrete OV flag for each device). This OV flag is only pertinent to the queue being selected for read operations at that time. Remember, that when in expansion mode only one multi-queue device can be read from at any moment in time, thus the OV flag provides status of the active queue on the read port. This connection of flag outputs to create a single flag requires that the OV flag output have a High-Impedance capability, such that when a queue selection is made only a single device drives the OV flag bus and all other OV flag outputs connected to the OV flag bus are placed into High-Impedance. The user does not have to select this High-Impedance state, a given multi-queue flow-control device will automatically place its OV flag output into High-Impedance when none of its queues are selected for read operations. When queues within a single device are selected for read operations, the OV flag output of that device will maintain control of the OV flag bus. Its OV flag will simply update between queue switches to show the respective queue output valid status. The multi-queue device places its OV flag output into High-Impedance based on the 3 bit ID code found in the 3 most significant bits of the read queue address bus, RDADD. If the 3 most significant bits of RDADD match the 3 bit ID code setup on the static inputs, ID0, ID1 and ID2 then the OV flag output of the respective device will be in a Low-Impedance state. If they do not match, then the OV flag output of the respective device will be in a High-Impedance state. See Figure 14, Output Valid Flag Timing for details of flag operation, including when more than one device is connected in expansion. OUTPUT VALID FLAG OPERATION The multi-queue flow-control device provides a single Output Valid flag output, OV. The OV provides an empty status or data output valid status for the data word currently available on the output register of the read port. The rising edge of an RCLK cycle that places new data onto the output register of the read port, also updates the OV flag to show whether or not that new data word is actually valid. Internally the multi-queue flow-control device monitors and maintains a status of the empty condition of all queues within it, however only the queue that is selected for read operations has its output valid (empty) status output to the OV flag, giving a valid status for the word being read at that time. The nature of the first word fall through operation means that when the last data word is read from a selected queue, the OV flag will go HIGH on the next enabled read, that is, on the next rising edge of RCLK while REN is LOW. When queue switches are being made on the read port, the OV flag will switch to show status of the new queue in line with the data output from the new queue. ALMOST FULL FLAG As previously mentioned the multi-queue flow-control device provides a single Programmable Almost Full flag output, PAF. The PAF flag output provides a status of the almost full condition for the active queue currently selected on the write port for write operations. Internally the multi-queue flow-control device monitors and maintains a status of the almost full condition of all queues within it, however only the queue that is selected for write operations has its full status output to the PAF flag. This dedicated flag is often referred to as the “active queue almost full flag”. The position of the PAF flag boundary within a queue can be at any point within that queues depth. This location can be user programmed via the serial port or one of the default values (8 or 128) can be selected if the user has performed default programming. 25 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits As mentioned, every queue within a multi-queue device has its own almost full status, when a queue is selected on the write port, this status is output via the PAF flag. The PAF flag value for each queue is programmed during multi-queue device programming (along with the number of queues, queue depths and almost empty values). The PAF offset value, m, for a respective queue can be programmed to be anywhere between ‘0’ and ‘D’, where ‘D’ is the total memory depth for that queue. The PAF value of different queues within the same device can be different values. When queue switches are being made on the write port, the PAF flag output will switch to the new queue and provide the user with the new queue status, on the third cycle after a new queue selection is made, on the same WCLK cycle that data can actually be written to the new queue. That is, a new queue can be selected on the write port via the WRADD bus, WADEN enable and a rising edge of WCLK. On the third rising edge of WCLK following a queue selection, the PAF flag output will show the full status of the newly selected queue. The PAF is flag output is triple register buffered, so when a write operation occurs at the almost full boundary causing the selected queue status to go almost full the PAF will go LOW 3 WCLK cycles after the write. The same is true when a read occurs, there will be a 3 WCLK cycle delay after the read operation. So the PAF flag delays are: from a write operation to PAF flag LOW is 2 WCLK + tWAF The delay from a read operation to PAF flag HIGH is tSKEW2 + WCLK + tWAF Note, if tSKEW is violated there will be one added WCLK cycle delay. The PAF flag is synchronous to the WCLK and all transitions of the PAF flag occur based on a rising edge of WCLK. Internally the multi-queue device monitors and keeps a record of the almost full status for all queues. It is possible that the status of a PAF flag maybe changing internally even though that flag is not the active queue flag (selected on the write port). A queue selected on the read port may experience a change of its internal almost full flag status based on read operations. The multi-queue flow-control device also provides a duplicate of the PAF flag on the PAF[7:0] flag bus, this will be discussed in detail in a later section of the data sheet. See Figures 23 and 24 for Almost Full flag timing and queue switching. ALMOST EMPTY FLAG As previously mentioned the multi-queue flow-control device provides a single Programmable Almost Empty flag output, PAE. The PAE flag output provides a status of the almost empty condition for the active queue currently selected on the read port for read operations. Internally the multi-queue flowcontrol device monitors and maintains a status of the almost empty condition of all queues within it, however only the queue that is selected for read operations has its empty status output to the PAE flag. This dedicated flag is often referred to as the “active queue almost empty flag”. The position of the PAE flag boundary within a queue can be at any point within that queues depth. This location can be user programmed via the serial port or one of the default values (8 or 128) can be selected if the user has performed default programming. As mentioned, every queue within a multi-queue device has its own almost empty status, when a queue is selected on the read port, this status is output via the PAE flag. The PAE flag value for each queue is programmed during multiqueue device programming (along with the number of queues, queue depths and almost full values). The PAE offset value, n, for a respective queue can be programmed to be anywhere between ‘0’ and ‘D’, where ‘D’ is the total memory depth for that queue. The PAE value of different queues within the same device can be different values. When queue switches are being made on the read port, the PAE flag output will switch to the new queue and provide the user with the new queue status, on the third cycle after a new queue selection is made, on the same RCLK cycle that data actually falls through to the output register from the new queue. That COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES is, a new queue can be selected on the read port via the RDADD bus, RADEN enable and a rising edge of RCLK. On the third rising edge of RCLK following a queue selection, the data word from the new queue will be available at the output register and the PAE flag output will show the empty status of the newly selected queue. The PAE is flag output is triple register buffered, so when a read operation occurs at the almost empty boundary causing the selected queue status to go almost empty the PAE will go LOW 3 RCLK cycles after the read. The same is true when a write occurs, there will be a 3 RCLK cycle delay after the write operation. So the PAE flag delays are: from a read operation to PAE flag LOW is 2 RCLK + tRAE The delay from a write operation to PAE flag HIGH is tSKEW2 + RCLK + tRAE Note, if tSKEW is violated there will be one added RCLK cycle delay. The PAE flag is synchronous to the RCLK and all transitions of the PAE flag occur based on a rising edge of RCLK. Internally the multi-queue device monitors and keeps a record of the almost empty status for all queues. It is possible that the status of a PAE flag maybe changing internally even though that flag is not the active queue flag (selected on the read port). A queue selected on the write port may experience a change of its internal almost empty flag status based on write operations. The multi-queue flow-control device also provides a duplicate of the PAE flag on the PAE[7:0] flag bus, this will be discussed in detail in a later section of the data sheet. See Figures 25 and 26 for Almost Empty flag timing and queue switching. POWER DOWN (PD) This device has a power down feature intended for reducing power consumption for HSTL/eHSTL configured inputs when the device is idle for a long period of time. By entering the power down state certain inputs can be disabled, thereby significantly reducing the power consumption of the part. All WEN and REN signals must be disabled for a minimum of four WCLK and RCLK cycles before activating the power down signal. The power down signal is asynchronous and needs to be held LOW throughout the desired powerdowntime. During power down, the following conditions for the inputs/outputs signals are: • All data in Queue(s) memory are retained. • All data inputs become inactive. • All write and read pointers maintain their last value before power down. • All enables, chip selects, and clock input pins become inactive. • All data outputs become inactive and enter high-impedance state. • All flag outputs will maintain their current states before power down. • All programmable flag offsets maintain their values. • All echo clocks and enables will become inactive and enter highimpedance state. • The serial programming and JTAG port will become inactive and enter high-impedance state. • All setup and configuration CMOS static inputs are not affected, as these pins are tied to a known value and do not toggle during operation. All internal counters, registers, and flags will remain unchanged and maintain their current state prior to power down. Clock inputs can be continuous and freerunning during power down, but will have no affect on the part. However, it is recommended that the clock inputs be low when the power down is active. To exit power down state and resume normal operations, disable the power down signal by bringing it HIGH. There must be a minimum of 1µs waiting period before read and write operations can resume. The device will continue from where it had stopped and no form of reset is required after exiting power down state. The power down feature does not provide any power savings when the inputs are configured for LVTTL operation. However, it will reduce the current for I/Os that are not tied directly to VCC or GND. See Figure 34, Power Down Operation, for the associated timing diagram. 26 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES TABLE 4 — FLAG OPERATION BOUNDARIES & TIMING I/O Set-Up Output Valid, OV Flag Boundary OV Boundary Condition I/O Set-Up Full Flag, FF Boundary FF Boundary Condition In36 to out36 (Almost Empty Mode) (Both ports selected for same queue when the 1st Word is written in) OV Goes LOW after 1st Write (see note 1 below for timing) In36 to out36 (Both ports selected for same queue when the 1st Word is written in) FF Goes LOW after D+1 Writes (see note below for timing) In36 to out36 (Packet Mode) (Both ports selected for same queue when the 1st Word is written in) OV Goes LOW after 1st Write (see note 2 below for timing) In36 to out36 (Write port only selected for queue when the 1st Word is written in) FF Goes LOW after D Writes (see note below for timing) In36 to out18 (Both ports selected for same queue when the 1st Word is written in) OV Goes LOW after 1st Write (see note 1 below for timing) In36 to out18 (Both ports selected for same queue when the 1st Word is written in) FF Goes LOW after D Writes (see note below for timing) In36 to out9 (Both ports selected for same queue when the 1st Word is written in) OV Goes LOW after 1st Write (see note 1 below for timing) In36 to out18 (Write port only selected for queue when the 1st Word is written in) FF Goes LOW after D Writes (see note below for timing) In18 to out36 (Both ports selected for same queue when the 1st Word is written in) OV Goes LOW after 1st Write (see note 1 below for timing) In36 to out9 (Both ports selected for same queue when the 1st Word is written in) FF Goes LOW after D Writes (see note below for timing) In9 to out36 (Both ports selected for same queue when the 1st Word is written in) OV Goes LOW after 1st Write (see note 1 below for timing) In36 to out9 (Write port only selected for queue when the 1st Word is written in) FF Goes LOW after D Writes (see note below for timing) In18 to out36 (Both ports selected for same queue when the 1st Word is written in) FF Goes LOW after ([D+1] x 2) Writes (see note below for timing) In18 to out36 (Write port only selected for queue when the 1st Word is written in) FF Goes LOW after (D x 2) Writes (see note below for timing) In9 to out36 (Both ports selected for same queue when the 1st Word is written in) FF Goes LOW after ([D+1] x 4) Writes (see note below for timing) In9 to out36 (Write port only selected for queue when the 1st Word is written in) FF Goes LOW after (D x 4) Writes (see note below for timing) NOTE: 1. OV Timing Assertion: Write to OV LOW: tSKEW1 + RCLK + tROV If tSKEW1 is violated there may be 1 added clock: tSKEW1 + 2 RCLK + tROV De-assertion: Read Operation to OV HIGH: tROV 2. OV Timing when in Packet Mode (36 in to 36 out only) Assertion: Write to OV LOW: tSKEW4 + RCLK + tROV If tSKEW4 is violated there may be 1 added clock: tSKEW4 + 2 RCLK + tROV De-assertion: Read Operation to OV HIGH: tROV NOTE: D = Queue Depth FF Timing Assertion: Write Operation to FF LOW: tWFF De-assertion: Read to FF HIGH: tSKEW1 + tWFF If tSKEW1 is violated there may be 1 added clock: tSKEW1+WCLK +tWFF Programmable Almost Full Flag, PAF & PAFn Bus Boundary I/O Set-Up PAF & PAFn Boundary in36 to out36 PAF/PAFn Goes LOW after (Both ports selected for same queue when the 1st D+1-m Writes Word is written in until the boundary is reached) (see note below for timing) in36 to out36 PAF/PAFn Goes LOW after (Write port only selected for same queue when the D-m Writes 1st Word is written in until the boundary is reached) (see note below for timing) in36 to out18 PAF/PAFn Goes LOW after D-m Writes (see below for timing) in36 to out9 PAF/PAFn Goes LOW after D-m Writes (see below for timing) in18 to out36 PAF/PAFn Goes LOW after ([D+1-m] x 2) Writes (see note below for timing) in9 to out36 PAF/PAFn Goes LOW after ([D+1-m] x 4) Writes (see note below for timing) NOTE: D = Queue Depth m = Almost Full Offset value. Default values: if DF is LOW at Master Reset then m = 8 if DF is HIGH at Master Reset then m= 128 PAF Timing Assertion: Write Operation to PAF LOW: 2 WCLK + tWAF De-assertion: Read to PAF HIGH: tSKEW2 + WCLK + tWAF If tSKEW2 is violated there may be 1 added clock: tSKEW2 + 2 WCLK + tWAF PAFn Timing Assertion: Write Operation to PAFn LOW: 2 WCLK* + tPAF De-assertion: Read to PAFn HIGH: tSKEW3 + WCLK* + tPAF If tSKEW3 is violated there may be 1 added clock: tSKEW3 + 2 WCLK* + tPAF * If a queue switch is occurring on the write port at the point of flag assertion or de-assertion there may be one additional WCLK clock cycle delay. 27 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES TABLE 4 — FLAG OPERATION BOUNDARIES & TIMING (CONTINUED) Programmable Almost Empty Flag, PAE Boundary Programmable Almost Empty Flag Bus, PAEn Boundary I/O Set-Up PAE Assertion I/O Set-Up PAEn Boundary Condition in36 to out36 (Both ports selected for same queue when the 1st Word is written in until the boundary is reached) PAE Goes HIGH after n+2 Writes (see note below for timing) in36 to out18 (Both ports selected for same queue when the 1st Word is written in until the boundary is reached) PAE Goes HIGH after n+1 Writes (see note below for timing) in36 to out9 (Both ports selected for same queue when the 1st Word is written in until the boundary is reached) PAE Goes HIGH after n+1 Writes (see note below for timing) in36 to out36 (Both ports selected for same queue when the 1st Word is written in until the boundary is reached) in36 to out36 (Write port only selected for same queue when the 1st Word is written in until the boundary is reached) in36 to out18 in18 to out36 (Both ports selected for same queue when the 1st Word is written in until the boundary is reached) PAE Goes HIGH after ([n+2] x 2) Writes (see note below for timing) in9 to out36 (Both ports selected for same queue when the 1st Word is written in until the boundary is reached) PAE Goes HIGH after ([n+2] x 4) Writes (see note below for timing) PAEn Goes HIGH after n+2 Writes (see note below for timing) PAEn Goes HIGH after n+1 Writes (see note below for timing) PAEn Goes HIGH after n+1 Writes (see below for timing) PAEn Goes HIGH after n+1 Writes (see below for timing) PAEn Goes HIGH after ([n+2] x 2) Writes (see note below for timing) PAEn Goes HIGH after ([n+1] x 2) Writes (see note below for timing) PAEn Goes HIGH after ([n+2] x 4) Writes (see note below for timing) PAEn Goes HIGH after ([n+1] x 4) Writes (see note below for timing) NOTE: n = Almost Empty Offset value. Default values: if DF is LOW at Master Reset then n = 8 if DF is HIGH at Master Reset then n = 128 PAE Timing Assertion: Read Operation to PAE LOW: 2 RCLK + tRAE De-assertion: Write to PAE HIGH: tSKEW2 + RCLK + tRAE If tSKEW2 is violated there may be 1 added clock: tSKEW2 + 2 RCLK + tRAE in36 to out9 in18 to out36 (Both ports selected for same queue when the 1st Word is written in until the boundary is reached) in18 to out36 (Write port only selected for same queue when the 1st Word is written in until the boundary is reached) in9 to out36 (Both ports selected for same queue when the 1st Word is written in until the boundary is reached) in9 to out36 (Write port only selected for same queue when the 1st Word is written in until the boundary is reached) NOTE: n = Almost Empty Offset value. Default values: if DF is LOW at Master Reset then n = 8 if DF is HIGH at Master Reset then n = 128 PAEn Timing Assertion: Read Operation to PAEn LOW: 2 RCLK* + tPAE De-assertion: Write to PAEn HIGH: tSKEW3 + RCLK* + tPAE If tSKEW3 is violated there may be 1 added clock: tSKEW3 + 2 RCLK* + tPAE * If a queue switch is occurring on the read port at the point of flag assertion or de-assertion there may be one additional RCLK clock cycle delay. PACKET READY FLAG BUS, PRn BOUNDARY Assertion: Both the rising and falling edges of PRn are synchronous to RCLK. PRn Falling Edge occurs upon writing the first TEOP marker, on input D35, (assuming a TSOP marker, on input D34 has previously been written). i.e. a complete packet is available within a queue. Timing: From WCLK rising edge writing the TEOP word PR goes LOW after: tSKEW4 + 2 RCLK* + tPAE If tSKEW4 is violated PRn goes LOW after tSKEW4 + 3 RCLK* + tPAE *If a queue switch is occurring on the read port at the point of flag assertion there may be one additional RCLK clock cycle delay. De-assertion: PR Rising Edge occurs upon reading the last RSOP marker, from output Q34. i.e. there are no more complete packets available within the queue. Timing: From RCLK rising edge Reading the RSOP word the PR goes HIGH after: 3 RCLK* + tPAE *If a queue switch is occurring on the read port at the point of flag assertion or de-assertion there may be one additional RCLK clock cycle delay. PACKET READY FLAG, PR BOUNDARY Assertion: Both the rising and falling edges of PR are synchronous to RCLK. PR Falling Edge occurs upon writing the first TEOP marker, on input D35, (assuming a TSOP marker, on input D34 has previously been written). i.e. a complete packet is available within a queue. Timing: From WCLK rising edge writing the TEOP word PR goes LOW after: tSKEW4 + 2 RCLK + tPR If tSKEW4 is violated: PR goes LOW after tSKEW4 + 3 RCLK + tPR (Please refer to Figure 19, Data Input (Transmit) Packet Mode of Operation, for timing diagram). De-assertion: PR Rising Edge occurs upon reading the last RSOP marker, from output Q34. i.e. there are no more complete packets available within the queue. Timing: From RCLK rising edge Reading the RSOP word the PR goes HIGH after: 3 RCLK + tPR (Please refer to Figure 20, Data Output (Receive) Packet Mode of Operation for timing diagram). 28 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits PAFn - DIRECT BUS If FM is LOW at master reset then the PAFn bus operates in Direct (addressed) mode. In direct mode the user can address the quadrant of queues they require to be placed on to the PAFn bus. For example, consider the operation of the PAFn bus when 26 queues have been setup. To output status of the first quadrant, Queue[0:7] the WRADD bus is used in conjunction with the FSTR (PAF flag strobe) input and WCLK. The address present on the 2 least significant bits of the WRADD bus with FSTR HIGH will be selected as the quadrant address on a rising edge of WCLK. So to address quadrant 1, Queue[0:7] the WRADD bus should be loaded with “xxxxxx00”, the PAFn bus will change status to show the new quadrant selected 1 WCLK cycle after quadrant selection. PAFn[0:7] gets status of queues, Queue[0:7] respectively. To address the second quadrant, Queue[8:15], the WRADD address is “xxxxxx01”. PAFn[0:7] gets status of queues, Queue[8:15] respectively. To address the third quadrant, Queue[16:23], the WRADD address is “xxxxxx10”. PAF[0:7] gets status of queues, Queue[16:23] respectively. To address the fourth quadrant, Queue[24:31], the WRADD address is “xxxxxx11”. PAF[0:1] gets status of queues, Queue[24:25] respectively. Remember, only 26 queues were setup, so when quadrant 4 is selected the unused outputs PAF[2:7] will be don't care states. Note, that if a read or write operation is occurring to a specific queue, say queue ‘x’ on the same cycle as a quadrant switch which will include the queue ‘x’, then there may be an extra WCLK cycle delay before that queues status is correctly shown on the respective output of the PAFn bus. However, the active PAF flag will show correct status at all times. Quadrants can be selected on consecutive clock cycles, that is the quadrant on the PAFn bus can change every WCLK cycle. Also, data present on the input bus, Din, can be written into a Queue on the same WCLK rising edge that a quadrant is being selected, the only restriction being that a write queue selection and PAFn quadrant selection cannot be made on the same cycle. If 8 or less queues are setup then queues, Queue[0:7] have their PAF status output on PAF[0:7] constantly. When the multi-queue devices are connected in expansion of more than one device the PAFn busses of all devices are connected together, when switching between quadrants of different devices the user must utilize the 3 most significant bits of the WRADD address bus (as well as the 2 LSB’s). These 3 MSB’s correspond to the device ID inputs, which are the static inputs, ID0, ID1 & ID2. Please refer to Figure 29 PAFn - Direct Mode Quadrant Selection for timing information. Also refer to Table 1, Write Address Bus, WRADD. COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES devices hold their PAFn outputs in High-Impedance. When the master device has cycled all of its quadrants it passes a token to the next device in the chain and that device assumes control of the PAFn bus and then cycles its quadrants and so on, the PAFn bus control token being passed on from device to device. This token passing is done via the FXO outputs and FXI inputs of the devices (“PAF Expansion Out” and “PAF Expansion In”). The FXO output of the master device connects to the FXI of the second device in the chain and the FXO of the second connects to the FXI of the third and so on. The final device in a chain has its FXO connected to the FXI of the first device, so that once the PAFn bus has cycled through all quadrants of all devices, control of the PAFn will pass to the master device again and so on. The FSYNC of each respective device will operate independently and simply indicate when that respective device has taken control of the bus and is placing its first quadrant on to the PAFn bus. When operating in single device mode the FXI input must be connected to the FXO output of the same device. In single device mode a token is still required to be passed into the device for accessing the PAFn bus. Please refer to Figure 32, PAFn Bus – Polled Mode for timing information. PAEn/PRn FLAG BUS OPERATION The IDT72T51546/72T51556 multi-queue flow-control device can be configured for up to 32 queues, each queue having its own almost empty/ packet ready status. An active queue has its flag status output to the discrete flags, OV, PAE and PR, on the read port. Queues that are not selected for a read operation can have their PAE/PR status monitored via the PAEn/PRn bus. The PAEn/PRn flag bus is 8 bits wide, so that 8 queues at a time can have their status output to the bus. If 9 or more queues are setup within a device then there are 2 methods by which the device can share the bus between queues, "Direct" mode and "Polled" mode depending on the state of the FM (Flag Mode) input during a Master Reset. If 8 or less queues are setup within a device then each will have its own dedicated output from the bus. If 8 or less queues are setup in single device mode, it is recommended to configure the PAFn bus to polled mode as it does not require using the write address (WRADD). PAEn/PRn - DIRECT BUS If FM is LOW at master reset then the PAEn/PRn bus operates in Direct (addressed) mode. In direct mode the user can address the quadrant of queues they require to be placed on to the PAEn/PRn bus. For example, consider the operation of the PAEn/PRn bus when 26 queues have been setup. To output status of the first quadrant, Queue[0:7] the RDADD bus is used in conjunction with the ESTR (PAE/PR flag strobe) input and RCLK. The address present on the 2 least significant bits of the RDADD bus with ESTR HIGH will be selected as the quadrant address on a rising edge of RCLK. So to address quadrant 1, Queue[0:7] the RDADD bus should be loaded with “xxxxxx00”, the PAEn/PRn bus will change status to show the new quadrant selected 1 RCLK cycle after quadrant selection. PAEn[0:7] gets status of queues, Queue[0:7] respectively. To address the second quadrant, Queue[8:15], the RDADD address is “xxxxxx01”. PAEn[0:7] gets status of queues, Queue[8:15] respectively. To address the third quadrant, Queue[16:23], the RDADD address is “xxxxxx10”. PAE[0:7] gets status of queues, Queue[16:23] respectively. To address the fourth quadrant, Queue[24:31], the RDADD address is “xxxxxx11”. PAE[0:1] gets status of queues, Queue[24:25] respectively. Remember, only 26 queues were setup, so when quadrant 4 is selected the unused outputs PAE[2:7] will be don't care states. Note, that if a read or write operation is occurring to a specific queue, say queue ‘x’ on the same cycle as a quadrant switch which will include the queue ‘x’, then there may be an extra RCLK cycle delay before that queues status is correctly shown on the respective output of the PAEn/PRn bus. PAFn – POLLED BUS If FM is HIGH at master reset then the PAFn bus operates in Polled (looped) mode. In polled mode the PAFn bus automatically cycles through the 4 quadrants within the device regardless of how many queues have been setup in the part. Every rising edge of the WCLK causes the next quadrant to be loaded on the PAFn bus. The device configured as the master (MAST input tied HIGH), will take control of the PAFn after MRS goes LOW. For the whole WCLK cycle that the first quadrant is on PAFn the FSYNC (PAFn bus sync) output will be HIGH, for all other quadrants, this FSYNC output will be LOW. This FSYNC output provides the user with a mark with which they can synchronize to the PAFn bus, FSYNC is always HIGH for the WCLK cycle that the first quadrant of a device is present on the PAFn bus. When devices are connected in expansion mode, only one device will be set as the Master, MAST input tied HIGH, all other devices will have MAST tied LOW. The master device is the first device to take control of the PAFn bus and will place its first quadrant on the bus on the rising edge of WCLK after the MRS input goes HIGH. For the next 3 WCLK cycles the master device will maintain control of the PAFn bus and cycle its quadrants through it, all other 29 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES can synchronize to the PAEn/PRn bus, ESYNC is always HIGH for the RCLK cycle that the first quadrant of a device is present on the PAEn/PRn bus. When devices are connected in expansion mode, only one device will be set as the Master, MAST input tied HIGH, all other devices will have MAST tied LOW. The master device is the first device to take control of the PAEn/PRn bus and will place its first quadrant on the bus on the rising edge of RCLK after the MRS input goes LOW. For the next 3 RCLK cycles the master device will maintain control of the PAEn/PRn bus and cycle its quadrants through it, all other devices hold their PAEn/PRn outputs in High-Impedance. When the master device has cycled all of its quadrants it passes a token to the next device in the chain and that device assumes control of the PAEn/PRn bus and then cycles its quadrants and so on, the PAEn/PRn bus control token being passed on from device to device. This token passing is done via the EXO outputs and EXI inputs of the devices (“PAE Expansion Out” and “PAE Expansion In”). The EXO output of the master device connects to the EXI of the second device in the chain and the EXO of the second connects to the EXI of the third and so on. The final device in a chain has its EXO connected to the EXI of the first device, so that once the PAEn/PRn bus has cycled through all quadrants of all devices, control of the PAEn/PRn will pass to the master device again and so on. The ESYNC of each respective device will operate independently and simply indicate when that respective device has taken control of the bus and is placing its first quadrant on to the PAEn/PRn bus. When operating in single device mode the EXI input must be connected to the EXO output of the same device. In single device mode a token is still required to be passed into the device for accessing the PAEn bus. Please refer to Figure 33, PAEn/PRn Bus – Polled Mode for timing information. Quadrants can be selected on consecutive clock cycles, that is the quadrant on the PAEn/PRn bus can change every RCLK cycle. Also, data can be read out of a Queue on the same RCLK rising edge that a quadrant is being selected, the only restriction being that a read queue selection and PAEn/PRn quadrant selection cannot be made on the same RCLK cycle. If 8 or less queues are setup then queues, Queue[0:7] have their PAE/PR status output on PAE[0:7] constantly. When the multi-queue devices are connected in expansion of more than one device the PAEn/PRn busses of all devices are connected together, when switching between quadrants of different devices the user must utilize the 3 most significant bits of the RDADD address bus (as well as the 2 LSB’s). These 3 MSB’s correspond to the device ID inputs, which are the static inputs, ID0, ID1 & ID2. Please refer to Figure 28, PAEn/PRn - Direct Mode Quadrant Selection for timing information. Also refer to Table 2, Read Address Bus, RDADD. PAEn – POLLED BUS If FM is HIGH at master reset then the PAEn/PRn bus operates in Polled (looped) mode. In polled mode the PAEn/PRn bus automatically cycles through the 4 quadrants within the device regardless of how many queues have been setup in the part. Every rising edge of the RCLK causes the next quadrant to be loaded on the PAEn/PRn bus. The device configured as the master (MAST input tied HIGH), will take control of the PAEn/PRn after MRS goes LOW. For the whole RCLK cycle that the first quadrant is on PAEn/PRn the ESYNC (PAEn/ PRn bus sync) output will be HIGH, for all other quadrants, this ESYNC output will be LOW. This ESYNC output provides the user with a mark with which they 30 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits ECHO READ CLOCK (ERCLK) The Echo Read Clock output is provided in both HSTL and LVTTL mode, selectable via IOSEL. The ERCLK is a free-running clock output, it will always follow the RCLK input regardless of REN and RADEN. The ERCLK output follows the RCLK input with an associated delay. This delay provides the user with a more effective read clock source when reading data from the Qn outputs. This is especially helpful at high speeds when variables within the device may cause changes in the data access times. These variations in access time maybe caused by ambient temperature, supply voltage, device characteristics. The ERCLK output also compensates for any trace length delays between the Qn data outputs and receiving devices inputs. Any variations effecting the data access time will also have a corresponding effect on the ERCLK output produced by the Queue device, therefore the ERCLK output level transitions should always be at the same position in time relative to the data outputs. Note, that ERCLK is guaranteed by design to be slower than the slowest Qn, data output. Refer to Figure 3, Echo Read Clock and Data Output Relationship and Figure 27, Echo RCLK & Echo REN Operation for timing information. ECHO READ ENABLE (EREN) The Echo Read Enable output is provided in both HSTL and LVTTL mode, selectable via IOSEL. The EREN output is provided to be used in conjunction with the ERCLK output and provides the reading device with a more effective scheme for reading data from the Qn output port at high speeds. The EREN output is controlled by internal logic that behaves as follows: The EREN output is active LOW for the RCLK cycle that a new word is read out of the Queue. That is, a rising edge of RCLK will cause EREN to go active (LOW) if REN is active and the Queue is NOT empty. RCLK tERCLK tERCLK ERCLK tA COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES tD QSLOWEST(3) 5998 drw08 NOTES: 1. REN is LOW. OE is LOW. 2. tERCLK > tA, guaranteed by design. 3. Qslowest is the data output with the slowest access time, tA. 4. Time, tD is greater than zero, guaranteed by design. Figure 3. Echo Read Clock and Data Output Relationship 31 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits BYTE ORDER ON INPUT PORT: BYTE ORDER ON OUTPUT PORT: BM IW OW L L L D35-D27 D26-D18 A B Q35-Q27 A D17-D9 C Q26-Q18 B COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES D8-D0 D Q17-Q9 Q8-Q0 C D Write to Queue Read from Queue (a) x36 INPUT to x36 OUTPUT Q35-Q27 BM IW OW H L L Q35-Q27 Q26-Q18 Q26-Q18 Q17-Q9 Q8-Q0 C D Q17-Q9 Q8-Q0 A B 1st: Read from Queue 2nd: Read from Queue (b) x36 INPUT to x18 OUTPUT Q35-Q27 BM IW OW H L H Q26-Q18 Q17-Q9 Q8-Q0 D Q35-Q27 Q26-Q18 Q17-Q9 Q8-Q0 C Q35-Q27 Q26-Q18 Q17-Q9 Q26-Q18 Q17-Q9 2nd: Read from Queue Q8-Q0 B Q35-Q27 1st: Read from Queue 3rd: Read from Queue Q8-Q0 A 4th: Read from Queue (c) x36 INPUT to x9 OUTPUT BYTE ORDER ON INPUT PORT: D35-D27 D35-D27 BYTE ORDER ON OUTPUT PORT: BM IW OW H H L D26-D18 D26-D18 D17-D9 D8-D0 A B D17-D9 D8-D0 C D Q35-Q27 Q26-Q18 Q17-Q9 Q8-Q0 C D A B 1st: Write to Queue 2nd: Write to Queue Read from Queue (d) x18 INPUT to x36 OUTPUT BYTE ORDER ON INPUT PORT: D35-D27 D26-D18 D17-D9 D8-D0 A D35-D27 D26-D18 D17-D9 D8-D0 B D35-D27 D26-D18 D17-D9 D26-D18 D17-D9 BM IW OW H H H Q35-Q27 Q26-Q18 Q17-Q9 Q8-Q0 D C B A (e) x9 INPUT to x36 OUTPUT Figure 4. Bus-Matching Byte Arrangement 32 3rd: Write to Queue D8-D0 D BYTE ORDER ON OUTPUT PORT: 2nd: Write to Queue D8-D0 C D35-D27 1st: Write to Queue 4th: Write to Queue Read from Queue 5998 drw09 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES tRS MRS tRSS WEN REN tRSS tRSR SENI tRSS FSTR, ESTR tRSS WADEN, RADEN tRSS ID0, ID1, ID2 tRSS OW, IW, BM tRSS FM HIGH = Looped LOW = Strobed (Direct) tRSS HIGH = Master Device MAST LOW = Slave Device tRSS HIGH = Packet Ready Mode PKT LOW = Almost Empty tRSS DFM HIGH = Default Programming LOW = Serial Programming tRSS HIGH = Offset Value is 128 DF LOW = Offset value is 8 tRSF HIGH-Z if Slave Device FF LOGIC "0" if Master Device tRSF OV LOGIC "1" if Master Device HIGH-Z if Slave Device tRSF LOGIC "1" if Master Device PAF HIGH-Z if Slave Device tRSF HIGH-Z if Slave Device PAE LOGIC "0" if Master Device tRSF LOGIC "1" if Master Device PAFn HIGH-Z if Slave Device tRSF HIGH-Z if Slave Device PAEn tRSF LOGIC "0" if Master Device LOGIC "1" if Master Device PR HIGH-Z if Slave Device tRSF PRn LOGIC "1" if Master Device HIGH-Z if Slave Device tRSF LOGIC "1" if OE is LOW and device is Master Qn NOTES: 1. OE can toggle during this period. 2. PRS should be HIGH during a MRS. HIGH-Z if OE is HIGH or Device is Slave 5998 drw10 Figure 5. Master Reset 33 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits w-3 w-2 w-1 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES w w+1 w+2 w+3 WCLK tQH tQS WADEN tENS tENS WEN tAS tAH WRADD Qx tWFF FF tWAF PAF tPAF Active Bus PAF-Qx(5) tPRSS tPRSH PRS tPRSH tPRSS RCLK tENS tENS REN tQH tQS RADEN tAS RDADD tAH Qx tROV OV tRAE PAE tPAE Active Bus PAE-Qx(6) r-2 r-1 r r+1 r+2 r+3 r+4 5998 drw11 NOTES: 1. For a Partial Reset to be performed on a Queue, that Queue must be selected on both the write and read ports. 2. The queue must be selected a minimum of 3 clock cycles before the Partial Reset takes place, on both the write and read ports. 3. The Partial Reset must be LOW for a minimum of 1 WCLK and 1 RCLK cycle. 4. Writing or Reading to the queue (or a queue change) cannot occur until a minimum of 3 clock cycles after the Partial Reset has gone HIGH, on both the write and read ports. 5. The PAF flag output for Qx on the PAFn flag bus may update one cycle later than the active PAF flag. 6. The PAE flag output for Qx on the PAEn flag bus may update one cycle later than the active PAE flag. Figure 6. Partial Reset Master Reset Default Mode DFM = 0 MRS DFM Serial Input SENI SENO SI SO SCLK SENI MQn SENO SI MRS DFM MQ2 MQ1 Serial Enable MRS DFM SO SENI SENO SO SI SCLK Serial Loading Complete SCLK Serial Clock 5998 drw12 Figure 7. Serial Port Connection for Serial Programming 34 35 tSCKH tSCLK tSCKL tSDS tSENS B11 1st B12 HIGH - Z HIGH - Z tSDH 2nd 1st Device in Chain B1n nth tSENO tSDO B21 B21 1st B22 B22 2nd 2nd Device in Chain B2n nth B2n tSENO B81 1st B81 tSDOP B82 2nd B82 Final Device in Chain B8n nth B8n Figure 8. Serial Programming NOTES: 1. SENI can be toggled during serial loading. Once serial programming of a device is complete, the SENI and SI inputs become transparent. SENI → SENO and SI → SO. 2. DFM is LOW during Master Reset to provide Serial programming mode, DF is don't care. 3. When SENO of the final device is LOW no further serial loads will be accepted. 4. n = 19+(Qx72); where Q is the number of queues required for the IDT72T51546/72T51556. 5. This diagram illustrates 8 devices in expansion. 6. Programming of all devices must be complete (SENO of the final device is LOW), before any write or read port operations can take place, this includes queue selections. OV (Slave Device) RADEN/ ESTR RCLK WEN FF (Slave Device) WADEN/ FSTR WCLK SENO (MQ8) SENO (MQ2) SENO (MQ1) SO (MQ1) SI (MQ1) SENI (MQ1) SCLK MRS tRSR tPCWQ tQS tQH tQH tENS tWFF Programming Complete tPCRQ tQS tSENO tSENOP 5998 drw13 tROV tSENOP IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES 36 1st HIGH - Z HIGH - Z 3rd 1st Device in Chain 2nd nth tSENO NOTES: 1. This diagram illustrates multiple devices connected in expansion. The SENO of the final device in a chain is the "programming complete" signal. 2. SENI of the first device in the chain can be held LOW 3. The SENO of a device should connect to the SENI of the next device in the chain. The final device SENO is used to indicate programming complete. 4. When Default Programming is complete the SENO of the final device will go LOW. 5. SCLK is not used and can be tied LOW. 6. Programming of all devices must be complete (SENO of the final device is LOW), before any write or read port operations can take place, this includes queue selections. OV (Slave Device) RADEN/ ESTR RCLK WEN FF (Slave Device) WADEN/ FSTR SENO (MQ8) SENO (MQ2) SENO (MQ1) WCLK MRS WCLK Serial Enable (can be tied LOW) Default Mode DFM = 1 Master Reset SI SENI DFM MQ1 X 1st SI SENI DFM WCLK MQ2 2nd SO SENO MRS Final Device in Chain X nth tQS SI SENI DFM tPCRQ tQS tPCWQ tSENO WCLK MQn tQH SO SENO MRS tQH Programming Complete Serial Port Connection for Default Programming SO SENO MRS tSENO WCLK nth Figure 9. Default Programming 1st 2nd 2nd Device in Chain X tROV 5998 drw14 Serial Loading Complete tENS tWFF IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES 37 tQS tAS Qx *A* tQH tENS tAS tQS *C* Qy tDS tAH tQH tWFF *AA* Previous Q, Word, W Previous Q Status tAH *B* QX WD *D* tWFF tDH tQS tAS *BB* 1 Qy *E* tQH tAH No Writes Queue Full *F* *CC* 2 tA No Writes Queue Full *G* PFT *DD* 3 Qy WD-2 Previous Q, W+1 tWFF tDS *H* tA tDH tDS tDH Qy WD *J* *EE* Qy, W0 tDS tSKEW1 Qy WD-1 *I* tENS tWFF tDH tENH *K* Figure 10. Write Queue Select, Write Operation and Full Flag Operation NOTE: OE is active LOW. Cycle: *A* Queue, Qx is selected on the write port. The FF flag is providing status of a previously selected queue, within the same device. *AA* Queue, Qy is selected for read operations. *B* The FF flag provides status of previous queue for 3 WCLK cycles. *BB* Current word is kept on the output bus since REN is HIGH. *C* The FF flag output updates to show the status of Qx, it is not full. *CC* Word W+1 is read from the previous queue regardless of REN due to FWFT. *D* Word, Wd is written into Qx. This causes Qx to go full. *DD* The next available Word W0 of Qy is read out regardless of REN, 3 RCLK cycles after queue selection. This is FWFT operation. *E* Queue, Qy is selected within the same device as Qx. A write to Qx cannot occur on this cycle because it is full, FF is LOW. *EE* No reads occur, REN is HIGH. *F* Again, a write to Qx cannot occur on this cycle because it is full, FF is LOW. *FF* Word, W1 is read from Qy, this causes Qy to go “not full”, FF flag goes HIGH after time, tSKEW1 + tWFF. Note, if tSKEW1 is violated the time FF HIGH will be: tSKEW1 + WCLK + tWFF. *G* The FF flag updates after time tWFF to show that queue, Qy is not full. *GG* Word, W2 is read from Qy. *H* Word, Wd-2 is written into Qy. *I* Word, Wd-1 is written into Qy. *J* Word, Wd is written into Qy, this causes Qy to go full, FF goes LOW. *K* A write to Qy cannot occur on this cycle because it is full, FF is LOW. *L* Qy goes “not full” based on reading word W1 from Qy on cycle *FF*. Qout RDADD RADEN REN RCLK FF Din WADEN WRADD WEN WCLK *FF* tA *L* Qy, W1 *GG* tWFF tA 5998 drw15 Qy, W2 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES WCLK tENH tENS WEN tDS Dn tDH tDS tDH tDS tDH W3 W2 W1 tSKEW1 RCLK 1 2 tENS REN tA Qout tA Last Word Read Out of Queue W1 Qy FWFT tA W2 Qy FWFT tROV W3 Qy tROV OV NOTES: 1. Qy has previously been selected on both the write and read ports. 2. OE is LOW. 3. The First Word Latency = tSKEW1 + RCLK + tA. If tSKEW1 is violated an additional RCLK cycle must be added. Figure 11. Write Operations & First Word Fall Through 38 5998 drw16 tQS tAS 39 D1 Q27 Addr=001 11011 tQH tAH *B* tQS tAS *C* D1 Q5 tQS tAS 2 tWFF tDS *H* tA tSKEW1 WD tENS *G* D1 Q5 Addr=001 00101 tQH tAH *F* No Write WD 1 D1 Q5 *E* D1 Q27 tWFF tDH tENH Previous Q WX-1 tQ H tAH HIGH-Z tFFHZ tFFLZ tDS tENS *D* tWFF PFT Previous Q WX tDH tENH *I* 3 tA tWFF tQS tAS D2 Q9 *J* tQH tAH D1-Q5 tFFLZ tFFHZ Word W0 PFT *K* 5998 drw17 HIGH-Z Figure 12. Full Flag Timing in Expansion Mode NOTE: *AA* *BB* *CC* *DD* 1. REN = HIGH. Cycle: *A* Queue, Q27 of device 1 is selected on the write port. The FF flag of device 1 is in High-Impedance, the write port of device 2 was previously selected. WEN is HIGH so no write occurs. *AA* Queue, Q5 of device 1 is selected on the read port. *B* The FF flag stays in High-Impedance for 2 WCLK cycles. *BB* Word, Wx-1 is held on the outputs for 2 RCLK cycles after a read Queue switch. *C* The FF flag of device 2 goes to High-Impedance and the FF flag of device 1 goes to Low-Impedance, logic HIGH indicating that D1 Q27 is not full. WEN is HIGH so no write occurs. *CC* Word, Wx is read from the previously selected queue, (due to FWFT). *D* Word, Wd is written into Q27 of D1. This write operation causes Q27 to go full, FF goes LOW. *DD* The first word from Q5 of D1 selected on cycle *AA* is read out, this occurred regardless of REN due to FWFT. This read caused Q5 to go not full, therefore the FF flag will go HIGH after: tSKEW1 + tWFF. Note if tSKEW1 is violated the time to FF flag HIGH is tSKEW1 + WLCK + tWFF. *E* Queue, Q5 of device 1 is selected on the write port. No write occurs on this cycle. *F* The FF flag stays in High-Impedance for 2 WCLK cycles. *G* The FF flag updates to show the status of D1 Q5, it is not full, FF goes HIGH. *H* Word, Wd is written into Q5 of D1. This causes the queue to go full, FF goes LOW. *I* No write occurs regardless of WEN, the FF flag is LOW preventing writes. The FF flag goes HIGH due to the read from Q5 of D1 on cycle *CC*. (This read is not an enabled read, it is due to the FWFT operation). *J* Queue, Q9 of device 2 is selected on the write port. *K* The FF flag of device 1 goes to High-Impedance, this device was deselected on the write port on cycle *I*. The FF flag of device 2 goes to Low-Impedance and provides status of Q9 of D2. Qout RADEN RDADD RCLK FF (Device 2) HIGH-Z FF (Device 1) Din WADEN WRADD WEN WCLK *A* IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES QP Wn-3 tENS tA *B* QP Wn-2 Previous Q *A* tA tENH *C* QF tQH tAH tENS Previous Q, QP Wn-1 tQS tAS *D* *E* 1 tA PFT QP Wn *F* 2 tA QG 3 PFT QP Wn+1 tQS tAS *G* tA tQH tAH QF W0 *H* tA QF W1 *I* tA 40 Figure 13. Read Queue Select, Read Operation Cycle: *A* Word Wn-3 is read from a previously selected queue Qp on the read port. *B* Wn-2 is read. *C* Reads are disabled, Wn-1 remains on the output bus. *D* A new queue, QF is selected for read operations. *E* Word Wn-1 in Qp is read out. *F* The next word available in current queue QP, Wn+1 is read regardless of REN due to FWFT. *G* The next word available in the new queue, QF-W0 falls through to the output bus, again this is regardless of REN. A new queue, QG is selected for read operations. (This queue is an empty queue). *H* Word, W1 is read from QF. *I* Word, W2 is read from QF. *J* Word W2 from QF remains on the output bus because QG is empty. The Output Valid Flag, OV goes HIGH to indicate that the current word is not valid, i.e. QG is empty. W2 is the last word in QG. OV QOUT RADEN RDADD REN RCLK QF W2 *J* tROV 5998 drw18 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits *A* *B* *C* *D* *E* *F* COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES *G* *H* *I* *J* RCLK tENS REN tAH tAS RDADD tAS tQS tAH D1 Q15 D1 Q30 tQH tQS tQH RADEN tA Qout (Device 1) tA tA tA tOLZ D1 Q30 WD Last Word D1 Q15 D1 Q15 We Last Word PFT We-1 tROV tOVLZ HIGH-Z OV (Device 1) tROV tROV W0 Q15 D1 tROV tOVHZ OV (Device 2) tSKEW1 WCLK tENH tENS WEN tAS WRADD tAH D1 Q15 tQS tQ H WADEN tDS Din tDH D1 Q15 W0 5998 drw19 Cycle: *A* Queue 30 of Device 1 is selected for read operations. The OV is currently being driven by Device 2, a queue within device 2 is selected for reads. Device 2 also has control of Qout bus, its Qout outputs are in Low-Impedance. This diagram only shows the Qout outputs of device 1. (Reads are disabled). *B* Reads are now enabled. A word from the previously selected queue of Device 2 will be read out. *C* After a queue switch, there is a 3 RCLK latency for output data. *D* The Qout of Device 1 goes to Low-Impedance and word Wd is read from Q30 of D1. This happens to be the last word of Q30. Device 2 places its Qout outputs into High-Impedance, device 1 has control of the Qout bus. The OV flag of Device 2 goes to High-Impedance and Device 1 takes control of OV. The OV flag of Device 1 goes LOW to show that Wd of Q30 is valid. *E* Queue 15 of device 1 is selected for read operations. The last word of Q30 was read on the previous cycle, therefore OV goes HIGH to indicate that the data on the Qout is not valid (Q30 was read to empty). Word, Wd remains on the output bus. *F* The last word of Q30 remains on the Qout bus, OV is HIGH, indicating that this word has been previously read. *G* The next word (We-1), available from the newly selected queue, Q15 of device 1 is now read out. This will occur regardless of REN, 2 RCLK cycles after queue selection due to the FWFT operation. The OV flag updates 3 RCLK cycles after a queue selection. *H* The last word, We is read from Q15, this queue is now empty. *I* The OV flag goes HIGH to indicate that Q15 was read to empty on the previous cycle. *J* Due to a write operation the OV flag goes LOW and data word W0 is read from Q15. The latency is: tSKEW1 + 1*RCLK + tROV. Figure 14. Output Valid Flag Timing (In Expansion Mode) 41 QP WD tENS *A* tA tENH *B* Qn QP WD+1 tQS tAS *C* tQH tAH tENS *D* 1 tA tENH QP WD+2 *E* 2 tA QP WD+3 *F* 3 tA tQS tAS QP *G* 42 tQ H tAH *H* Qn WX Figure 15. Read Queue Selection with Reads Disabled Cycle: *A* Word Wd+1 is read from the previously selected queue, Qp. *B* Reads are disabled, word Wd+1 remains on the output bus. *C* A new queue, Qn is selected for read port operations. *D* Word, WD+2 of Qp is read out. *E* Word WD+3 of Qp is read out regardless of REN due to FWFT operation. *F* The next available word Wx of Qn is read out regardless of REN, 3 RCLK cycles after queue selection. This is FWFT operation. *G* The queue, Qp is again selected. *H* Current Word is kept on the output bus since REN is HIGH. *I* Word Wx+2 is read from Qn. This is read out regardless of REN due to FWFT operation. *J* Word WD+3 is read from Qp. *K* Word WD+4 is read from Qp. *L* Reads are disabled on this cycle, therefore no further reads occur. OV QOUT RADEN RDADD REN RCLK 1 tENS *I* 2 tA Qn WX+1 *J* 3 tA Qn WX+2 *K* tA 5998 drw20 QP WD+3 tENH *L* IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES tOLZ tQS tAS tOE QA *A* tQH tAH *C* 2 tENS Previous Data in O/P Register 1 *B* *D* 3 tROV tA tENH *E* PFT QA W0 tENS *F* tA QA W1 *G* tA QB QA W2 tQS tAS *H* tA tQH tAH QA W3 *I* 1 tA QA W4 2 *J* tA tROV tOHZ 3 43 Figure 16. Read Queue Select, Read Operation and OE Timing 5998 drw21 No Read QB is Empty *K* NOTES: 1. The Output Valid flag, OV is HIGH therefore the previously selected queue has been read to empty. The Output Enable input is Asynchronous, therefore the Qout output bus will go to Low-Impedance after time tOLZ. The data currently on the output register will be available on the output after time tOE. This data is the previous data on the output register, this is the last word read out of the previous queue. 2. In expansion mode the OE inputs of all devices should be connected together. This allows the output busses of all devices to be High-Impedance controlled. Cycle: *A* Queue A is selected for reads. No data will fall through on this cycle, the previous queue was read to empty. *B* No data will fall through on this cycle, the previous queue was read to empty. *C* Previous data kept on output bus since there is no read operation. *D* Word, W0 from QA is read out regardless of REN due to FWFT operation. The OV flag goes LOW indicating that Word W0 is valid. *E* Reads are disabled therefore word, W0 of QA remains on the output bus. *F* Reads are again enabled so word W1 is read from QA. *G* Word W2 is read from QA. *H* Queue, QB is selected on the read port. This queue is actually empty. Word, W3 is read from QA. *I* Word, W4 is read from QA. *J* Output Enable is taken HIGH, this is Asynchronous so the output bus goes to High-Impedance after time, tOHZ. *K* Output Valid flag, OV goes HIGH to indicate that QB is empty. Data on the output port is no longer valid. OV Qout OE RADEN RDADD REN RCLK IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES QA Data QA tDS tAS tDH tAH QA Data QB B 1 QA TEOP C NOTE: 1. Do not Write an SOP or EOP on "D" or "K". A filler word is needed. (D35) TSOP (D35) TEOP WEN Din WADEN WRADD WCLK A QB TSOP E QB Data F QB Data G H QB TEOP Figure 17. Writing in Packet Mode during a Queue change QA Dummy 2 D(1) tAS 1 QC I tAH J 2 QB Dummy tDS K(1) tDH 5998 drw22 QC TSOP IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits 44 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES QA tAS tA tAH QA Data QB B 1 QA Data C tA D 2 QA REOP NOTE: 1. Do not Read an SOP or EOP on "E" or "L". A filler word is needed. (Q34) RSOP (Q35) REOP REN Qout RADEN RDADD RCLK A tA QA “Dummy” QB RSOP F tA QB Data G tA QB Data H Figure 18. Reading in Packet Mode during a Queue change tA E(1) QC QB REOP tAS I tAH J 1 K 2 tA QB “Dummy” L(1) tA 5998 drw23 QC RSOP IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits 45 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES 46 tDS tDS tDS tDS tENS P1Wo tDH tDH tDH tDH tDS tDH P1Wn-3 *B* P1Wn-1 Last Word Read Out P1Wn-2 tDS tDS tDS tDH tDH tDH tENH P1Wn *C* tSKEW4 tSKEW5 Figure 19. Data Input (Transmit) Packet Mode of Operation NOTES: 1. REN is HIGH. 2. If tSKEW4 is violated PR may take one additional RCLK cycle. 3. If tSKEW5 is violated the OV may take one additional RCLK cycle. 4. PR will always go LOW on the same cycle or 1 cycle ahead of OV going LOW, (assuming the last word of the packet is the last word in the queue). 5. In Packet mode, words cannot be read from a queue until a complete packet has been written into that queue, regardless of REN. Qn OV PR RCLK TMOD2 (D32) TAEOP/ TMOD1 (D33) TEOP (D35) TSOP (D34) D0D31 WEN WCLK *A* tPR tA tROV 5998 drw24 P1Wo IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES 47 tENS tA P1Wo *B* tA P1W1 *C* tA tPR P1W2 *D* tA P1Wn-3 tA P1Wn-2 tA P1Wn-1 *E* tA tRO V 5998 drw35 P1Wn tA Figure 20. Data Output (Receive) Packet Mode of Operation NOTE: 1. In Packet mode, words cannot be read from a queue until a complete packet has been written into that queue, regardless of REN. 2. The PR flag will go HIGH on cycle *C* regardless of REN. 3. The OV flag will go HIGH (preventing further reads), when the last complete packet has been read out. If there is a partial packet (an incomplete packet) in the queue the OV flag will remain HIGH until further writes have completed the packet. OV RMOD2 (Q32) RAEOP/ RMOD1 (Q33) Q0-Q31 REOP (Q35) RSOP (Q34) PR REN RCLK *A* IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits NULL QUEUE SELECT *A* *B* COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES SELECT NEW QUEUE *D* *C* *E* *G* *F* RCLK tAS tAH tAS tQS tQH tQS tAS tAH 00100000 RDADD tAH 00000100 tQH RADEN Null-Q tENS tENH REN Qout Q1 Wn-4 tA tA tA Q1 Wn-3 Q1 Wn-2 tA tA Q1 Wn-1 Q4 W0 Q1 Wn tROV FWFT tROV OV 5998 drw26 NOTES: 1. The purpose of the Null queue operation is so that the user can stop reading a block (packet) of data from a queue without filling the 2 stage output pipeline with the next words from that queue. 2. Please see Figure 22, Null Queue Flow Diagram. Cycle: *A* Null Q of device 0 is selected, when word Wn-3 from previously selected Q1 is read. *C* REN is HIGH and Wn (Last Word of the Packet) of Q1 is pipelined onto the O/P register. Note: *B* and *C* are a minimum 3 RCLK cycles between queue selects. *D* The Null Q is seen as an empty Queue on the read side, therefore Wn of Q1 remains in the O/P register and OV goes HIGH. A new queue, Q4 is selected. *G* 1st word, W0 of Q4 falls through present on the O/P register after 3 RCLK cycles after the queue select. Figure 21. Read Operation and Null Queue Select *A* *B* *C* *D* *E* *F* *G* Queue 1 Memory Queue 1 Memory Null Queue Null Queue Null Queue Queue 4 Memory Queue 4 Memory Q1 Wn Q1 Wn O/P Reg. Qn Wn-2 Q1 Wn O/P Reg. Q1 Wn-1 Q1 Wn O/P Reg. Q1 Wn Q1 Wn O/P Reg. Q1 Wn Q4 W0 O/P Reg. Q1 Wn Q4 W1 O/P Reg. Q1 Wn O/P Reg. Q4 W0 5998 drw27 Figure 22. Null Queue Flow Diagram 48 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits *B* *A* *D* *C* COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES *G* *F* *E* WCLK *H* 2 1 tENH tENS WEN tAH tAS WRADD tAS D1 Q5 tQS tAH D1 Q9 tQH tQH tQS WADEN tDS Din tDH WD-m D1 Q5 tWAF tWAF tAFLZ HIGH-Z PAF (Device 1) tFFHZ PAF (Device 2) 5998 drw28 Cycle: *A* Queue 5 of Device 1 is selected on the write port. A queue within Device 2 had previously been selected. The PAF output of device 1 is High-Impedance. *B* No write occurs. *C* No write occurs. *D* Word, Wd-m is written into Q5 causing the PAF flag to go from LOW to HIGH. The flag latency is 3 WCLK cycles + tWAF. *E* Queue 9 in device 1 is now selected for write operations. This queue is not almost full, therefore the PAF flag will update after a 3 WCLK + tWAF latency. *F* The PAF flag goes LOW based on the write 2 cycles earlier. *G* No write occurs. *H* The PAF flag goes HIGH due to the queue switch to Q9. Figure 23. Almost Full Flag Timing and Queue Switch tCLKL tCLKL WCLK 1 2 1 tENS tENH WEN tWAF PAF tWAF (2) D - m words in Queue D - (m+1) words in Queue tSKEW2 D-(m+1) words in Queue RCLK tENS REN tENH 5998 drw29 NOTE: 1. The waveform here shows the PAF flag operation when no queue switches are occurring and a queue selected on both the write and read ports is being written to then read from at the almost full boundary. Flag Latencies: Assertion: 2*WCLK + tWAF De-assertion: tSKEW2 + WCLK + tWAF If tSKEW2 is violated there will be one extra WCLK cycle. Figure 24. Almost Full Flag Timing 49 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits *B* *A* *C* COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES *E* *D* *F* *G* *H* RCLK REN HIGH tAH tAS RDADD tAS tAH D1 Q30 tQS D1 Q15 tQH tQH tQS RADEN tOLZ Qout tA tA HIGH-Z D1 Q30 Wn tA D1 Q15 W0 D1 Q15 W1 tRAE tRAE tAELZ PAE (Device 1) tA D1 Q30 Wn+1 HIGH-Z tAEHZ PAE (Device 2) HIGH-Z 5998 drw30 Cycle: *A* Queue 30 of Device 1 is selected on the read port. A queue within Device 2 had previously been selected. The PAE flag output and the data outputs of device 1 are High-Impedance. *B* No read occurs. *C* No read occurs. *D* The PAE flag output now switches to device 1. Word, Wn is read from Q30 due to the FWFT operation. This read operation from Q30 is at the almost empty boundary, therefore PAE will go LOW 2 RCLK cycles later. *E* Q15 of device 1 is selected. *F* The PAE flag goes LOW due to the read from Q30 2 RCLK cycles earlier. Word Wn+1 is read out due to the FWFT operation. *G* Word, W0 is read from Q15 due to the FWFT operation. *H* The PAE flag goes HIGH to show that Q15 is not almost empty. Figure 25. Almost Empty Flag Timing and Queue Switch tCLKL tCLKH WCLK tENS tENH WEN PAE n+1 words in Queue tSKEW2 n+2 words in Queue n+1 words in Queue tRAE tRAE RCLK 1 tENS REN 2 tENH 5998 drw31 NOTE: 1. The waveform here shows the PAE flag operation when no queue switches are occurring and a queue selected on both the write and read ports is being written to then read from at the almost empty boundary. Flag Latencies: Assertion: 2*RCLK + tRAE De-assertion: tSKEW2 + RCLK + tRAE If tSKEW2 is violated there will be one extra RCLK cycle. Figure 26. Almost Empty Flag Timing 50 Cycle: *A* *B* *C, D* *E* *F, G* *H* *I* QP Wn-3 tENS tA tCLKEN *B* QP Wn-2 tERCLK Previous Q *A* tA tENH tCLKEN *C* QF H tQ tAH tENS Previous Q, QP Wn-1 tQS tAS *D* 51 1 tA tCLKEN *E* 1 QG PFT tQS tAS QP Wn+1 tA 2 *G* PFT 2 QP Wn *F* Figure 27. Echo RCLK and ECHO REN Operation EREN follow REN provided that the current queue (Qp) is not empty. EREN stays active since a new word (Wn-1) from Qp is placed on the output bus. EREN goes HIGH since no new word has been placed on the output bus on this cycle. REN goes LOW, new word placed on output bus, so EREN goes LOW. EREN stays active since a new word from Qp has been placed on the output bus. W0 is the last word in QF thus OV goes HIGH. EREN goes HIGH since no new word has been placed on the output bus and QF is empty. OV QOUT RADEN RDADD EREN REN ERCLK RCLK tA tQH tAH *H* QF W0 tROV *I* 5998 drw32 tCLKEN IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES RCLK tQH tQS tQS tQH Device 1 Quadrant 3 Device 1 Quadrant 2 RDADD 001xxx11 001xxx10 tSTS tQS tQH Device 1 Quadrant 0 001xxx00 tSTS tSTH tSTH ESTR tPAE tPAE PAEn/ PRn Device 1 Quadrant 2 tPAE Device 1 Quadrant 3 Device 1 Quadrant 0 5998 drw33 NOTES: 1. Quadrants can be selected on consecutive cycles. 2. On an RCLK cycle that the ESTR is HIGH, the RADEN input must be LOW. 3. There is a latency of 2 RCLK for the PAEn bus to switch. Figure 28. PAEn/PRn - Direct Mode - Quadrant Selection WCLK tQH tQS tQS tQH Device 1 Quadrant 3 Device 1 Quadrant 1 WRADD 001xxx01 tSTS 001xxx11 tSTS tSTH tQS tQH Device 1 Quadrant 2 001xxx10 tSTH FSTR tPAF tPAF PAFn Device 1 Quadrant 1 tPAF Device 1 Quadrant 3 Device 1 Quadrant 2 5998 drw34 NOTES: 1. Quadrants can be selected on consecutive cycles. 2. On a WCLK cycle that the FSTR is HIGH, the WADEN input must be LOW. 3. There is a latency of 2 WCLK for the PAFn bus to switch. Figure 29. PAFn - Direct Mode - Quadrant Selection 52 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits *A* WCLK tQS *B* 1 *C* 2 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES *D* 3 *E* tQH tQS *F* *G* *H* tQS tQH tQH WADEN tSTS tSTH FSTR tENS tENS tENH tENH WEN tAH tAS WRADD D5Q24 100 11000 tAS tDH tDS tDS Wp+1 Wp Writes to Previous Q Dn tDH tDS Wp+2 tDH tAH tAS tAH D3Q8 011 01000 D4 quad 3 100 xxx10 Wn+1 D5Q24 Wn D5 Q24 Wx D3 Q8 tSKEW3 RCLK tQS tQH 1 2 3 3 2 1 RADEN tSTS tSTH ESTR tENS tENH REN tAH tAS RDADD Device 5 -Qn Prev PAEn tAS D5Q24 100 11000 tAH D5 quad 4 tA Wa D5 Q17 101 xxx11 tA Wa+1 D5 Q17 tA Wy D5 Q24 tA Wy+1 D5 Q24 tA Wy+2 D5 Q24 Previous value loaded on to PAE bus tPAEZL tPAEHZ Device 5 PAEn Bus PAEn Previous value loaded on to PAE bus tRAE Device 5 PAE Wy+3 D5 Q24 xxxx xxx1 D5Quad 4 xxxx xxx0 D5Quad4 xxxx xxx1 D5Quad 4 xxxx xxx0 D5Quad4 tRAE tRAE D5 Q24 status D5 Q17 Status *AA* tPAE *BB* *CC* *DD* *EE* 5998 drw35 *FF* *GG* Cycle: *A* Queue 24 of Device 5 is selected for write operations. Word, Wp is written into the previously selected queue. *AA* Queue 24 of Device 5 is selected for read operations. A quadrant from another device has control of the PAEn bus. The discrete PAE output of device 5 is currently in High-Impedance and the PAE active flag is controlled by the previously selected device. *B* Word Wp+1 is written into the previously selected queue. *BB* Current Word is kept on the output bus since REN is HIGH. *C* Word Wp+2 is written into the previously selected queue. *CC* Word Wa+1 of D5 Q17 is read due to FWFT. *D* Word, Wn is written into the newly selected queue, Q24 of D5. This write will cause the PAE flag on the read port to go from LOW to HIGH (not almost empty) after time, tSKEW3 + RCLK + tRAE (if tSKEW3 is violated one extra RCLK cycle will be added). *DD* Word, Wy from the newly selected queue, Q24 will be read out due to FWFT operation. Quadrant 4 of Device 5 is selected on the PAEn bus. Q24 of device 5 will therefore have is PAE status output on PAE[0]. There is a single RCLK cycle latency before the PAEn bus changes to the new selection. *E* Queue 8 of Device 3 is selected for write operations. Word Wn+1 is written into Q24 of D5. *EE* Word, Wy+1 is read from Q24 of D5. *F* No writes occur. *FF* Word, Wy+2 is read from Q24 of D5. The PAEn bus changes control to D5, the PAEn outputs of D5 go to Low-Impedance and quadrant 4 is placed onto the outputs. The device of the previously selected quadrant now places its PAEn outputs into High-Impedance to prevent bus contention. The discrete PAE flag will go HIGH to show that Q24 of D5 is not almost empty. Q24 of device 5 will have its PAE status output on PAE[0]. *G* Quadrant 3 of device 4 is selected on the write port for the PAFn bus. *GG* The PAEn bus updates to show that Q24 of D5 is almost empty based on the reading out of word, Wy+1. The discrete PAE flag goes LOW to show that Q24 of D5 is almost empty based on the reading of Wy+1. *H* Word, Wx is written into Q8 of D3. Figure 30. PAEn - Direct Mode, Flag Operation 53 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits *A* *B* *C* *D* COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES *E* *F* *G* RCLK tQS *I* tQH tQS tQH *H* RADEN tSTH tSTS ESTR REN tAS RDADD tAH tAH tAS D0Q31 000 11111 tAH tAS D6Q2 110 00010 D7 quad 1 111 xxx00 OE tA tA tOLZ Qout WX Prev. Q WX +1 Prev. Q tSKEW3 WCLK tA WD - M + 2 D0 Q31 WD-M+1 D0 Q31 1 tSTS tA 2 W0 D6 Q2 3 tSTH FSTR tAH tAS WRADD tAS D0 quad4 tAH D0 Q31 tENS 000 xxx11 tENH WEN tQH tQS WADEN tDS tDH tDS tDH Wy+1 Word Wy D0 Q31 D0 Q31 tPAF Din tPAFLZ Device 0 PAFn D0Quad4 tDS tDH Wy+2 D0 Q31 tPAF 0xxx xxxx D0Quad4 1xxx xxxx D0Quad4 0xxx xxxx 0xxx xxxx D0Quad4 1xxx xxxx D0Quad4 0xxx xxxx HIGH-Z Bus PAFn DXQuad y Prev. PAFn DXQuad y Device 0 PAF D0Quad4 tPAFHZ HIGH-Z tPAFLZ tWAF HIGH - Z *AA* *BB* 5998 drw36 *CC* *DD* *EE* *FF* *GG* Cycle: *A* Queue 31 of device 0 is selected for read operations. The last word in the output register is available on Qout. OE was previously taken LOW so the output bus is in Low-Impedance. *AA* Quadrant 4 of device 0 is selected for the PAFn bus. The bus is currently providing status of a previously selected quadrant, Quad Y of device X. *B* No read operation. *BB* Queue 31 of device 0 is selected on the write port. *C* Word, Wx+1 is read out from the previous queue due to the FWFT effect. *CC* PAFn continues to show status of Quad4 D0. The PAFn bus is updated with the quadrant selected on the previous cycle, D0 Quad 4. PAF[7] is LOW showing the status of queue 31. The PAFn outputs of the device previously selected on the PAFn bus go to High-Impedance. *D* A new quadrant, Quad 1 of Device 7 is selected for the PAFn bus. Word, Wd-m+1 is read from Q31 D0 due to the FWFT operation. This read is at the PAFn boundary of queue D0 Q31. This read will cause the PAF[7] output to go from LOW to HIGH (almost full to not almost full), after a delay tSKEW3 + WCLK + tPAF. If tSKEW3 is violated add an extra WCLK cycle. *DD* No write operation. *E* No read operations occur, REN is HIGH. *EE* PAF[7] goes HIGH to show that D0 Q31 is not almost empty due to the read on cycle *C*. The active queue PAF flag of device 0 goes from High-Impedance to Low-Impedance. Word, Wy is written into D0 Q31. *F* Queue 2 of Device 6 is selected for read operations. *FF* Word, Wy+1 is written into D0 Q31. *G* Word, Wd-m+2 is read out due to FWFT operation. *GG* PAF[7] and the discrete PAF flag go LOW to show the write on cycle *DD* causes Q31 of D0 to again go almost full. Word, Wy+2 is written into D0 Q31. *H* No read operation. *I* Word, W0 is read from Q0 of D6, selected on cycle *F*, due to FWFT. Figure 31. PAFn - Direct Mode, Flag Operation 54 tFSYNC D0Quad1 tPAF D0Quad2 tPAF tFSYNC NOTE: 1. This diagram is based on 3 devices connected in expansion mode. PAFn FXI0 FXO2 / (SLAVE) FSYNC2 FXI2 FXO1 / (SLAVE) FSYNC1 FXI1 FXO0 / (MASTER) FSYNC0 WCLK D0Quad3 tPAF tFXO D1Quad1 tPAF D1Quad2 tPAF tFSYNC D1Quad3 tPAF tFXO Figure 32. PAFn Bus - Polled Mode D0Quad4 tPAF tFSYNC tFXO D1Quad4 tPAF tFSYNC D2Quad1 tPAF tFXO D2Quad2 tPAF tFSYNC D2Quad3 tPAF tFXO D2Quad4 tPAF tFSYNC D0Quad1 tPAF tFXO 5998 drw37 D0Quad2 tPAF tFSYNC IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits 55 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES tESYNC D0Quad1 tPAE D0Quad2 tPAE tESYNC D0Quad3 tPAE tEXO NOTE: 1. This diagram is based on 3 devices connected in expansion mode. PAEn EXI0 EXO2 / ESYNC2 EXI2 EXO1 / ESYNC1 EXI1 EXO0 / ESYNC0 RCLK D1Quad1 tPAE D1Quad2 tPAE tESYNC D1Quad3 tPAE tEXO D1Quad4 tPAE tESYNC Figure 33. PAEn/PRn Bus - Polled Mode D0Quad4 tPAE tESYNC tEXO D2Quad1 tPAE tEXO D2Quad2 tPAE tESYNC D2Quad3 tPAE tEXO D2Quad4 tPAE tESYNC D0Quad1 tPAE tEXO 5998 drw38 D0Quad2 tPAE tESYNC IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits 56 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES WCLK WEN tDH tDS D[39:0] WD10 tDS tDH tDS WD11 WD12 tDH tDS WD13 1ns (1) 1 RCLK 2 3 4 REN tA Q[39:0] WD1 tA WD2 tPDHZ(7) tA WD3 tPDLZ(2) Hi-Z WD4 tA WDH WDS tPDH(2) tPDH(2) tPDL PD tERCLK Hi-Z ERCLK tEREN tEREN Hi-Z EREN 5998 drw39 NOTES: 1. All read and write operations must have ceased a minimum of 4 WCLK and 4 RCLK cycles before power down is asserted. 2. When the PD input becomes deasserted, there will be a 1µs waiting period before read and write operations can resume. All input and output signals will also resume after this time period. 3. Set-up and configuration static inputs are not affected during power down. 4. Serial programming and JTAG programming port are inactive during power down. 5. RCS = 0, WCS = 0 and OE = 0. These signals can toggle during and after power down. 6. All flags remain active and maintain their current states. 7. During power down, all outputs will be in high-impedance. Figure 34. Power Down Operation 57 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES Serial Programming Data Input Serial Enable SENI Data Bus Write Clock Write Enable Write Queue Select SI EXI Output Data Bus Q0-Q35 WEN Almost Full Flag Serial Clock Read Queue Select RDADD WRADD DEVICE 1 FSTR Read Address RADEN Empty Strobe ESTR Programmable Almost Empty PAEn PAFn Full Flag Read Enable REN WADEN Full Sync1 Read Clock RCLK WCLK Write Address Full Strobe Programmable Almost Full FXI D0-D35 Empty Sync 1 ESYNC FSYNC Output Valid Flag OV FF PAF Almost Empty Flag PAE Packet Reads PR SCLK SENO SO FXO EXO SENI SI FXI EXI Q0-Q35 D0-D35 WCLK RCLK REN WEN WRADD RDADD RADEN WADEN DEVICE 2 FSTR Full Sync2 PAFn FSYNC ESTR PAEn ESYNC FF OV PAF PAE Empty Sync 2 PR SCLK SENO SO FXO EXO SENI SI FXI EXI Q0-Q35 D0-D35 WCLK RCLK REN WEN WRADD WADEN Full Sync n DEVICE n FSTR PAFn FSYNC RDADD RADEN ESTR PAEn ESYNC FF Empty Sync n OV PAF PAE PR SCLK SENO FXO EXO DONE 5998 drw40 NOTES: 1. If devices are configured for Direct operation of the PAFn/PAEn flag busses the FXI/EXI of the MASTER device should be tied LOW. All other devices tied HIGH. The FXO/EXO outputs are DNC (Do Not Connect). 2. Q outputs must not be mixed between devices, i.e. Q0 of device 1 must connect to Q0 of device 2, etc. Figure 35. Multi-Queue Expansion Diagram 58 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES The Standard JTAG interface consists of four basic elements: Test Access Port (TAP) • • TAP controller • Instruction Register (IR) • Data Register Port (DR) JTAG INTERFACE Five additional pins (TDI, TDO, TMS, TCK and TRST) are provided to support the JTAG boundary scan interface. The IDT72T51546/72T51556 incorporates the necessary tap controller and modified pad cells to implement the JTAG facility. Note that IDT provides appropriate Boundary Scan Description Language program files for these devices. The following sections provide a brief description of each element. For a complete description refer to the IEEE Standard Test Access Port Specification (IEEE Std. 1149.1-1990). The Figure below shows the standard Boundary-Scan Architecture DeviceID Reg. Mux Boundary Scan Reg. Bypass Reg. TDO TDI T A TMS TCLK TRST P TAP clkDR, ShiftDR UpdateDR Controller Instruction Decode clklR, ShiftlR UpdatelR Instruction Register Control Signals 5998 drw41 Figure 36. Boundary Scan Architecture THE TAP CONTROLLER The Tap controller is a synchronous finite state machine that responds to TMS and TCLK signals to generate clock and control signals to the Instruction and Data Registers for capture and update of data. TEST ACCESS PORT (TAP) The Tap interface is a general-purpose port that provides access to the internal of the processor. It consists of four input ports (TCLK, TMS, TDI, TRST) and one output port (TDO). 59 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits 1 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES Test-Logic Reset 0 0 Run-Test/ Idle 1 SelectDR-Scan 1 SelectIR-Scan 1 0 1 0 Capture-IR 1 Capture-DR 0 0 0 Shift-DR Shift-IR 1 1 Input = TMS EXit1-DR 1 0 0 Pause-IR 1 1 Exit2-DR Exit2-IR 0 1 1 Update-IR Update-DR 1 1 Exit1-IR 0 0 Pause-DR 0 0 1 0 0 5998 drw42 NOTES: 1. Five consecutive TCK cycles with TMS = 1 will reset the TAP. 2. TAP controller does not automatically reset upon power-up. The user must provide a reset to the TAP controller (either by TRST or TMS). 3. TAP controller must be reset before normal Queue operations can begin. Figure 37. TAP Controller State Diagram Refer to the IEEE Standard Test Access Port Specification (IEEE Std. 1149.1) for the full state diagram. All state transitions within the TAP controller occur at the rising edge of the TCLK pulse. The TMS signal level (0 or 1) determines the state progression that occurs on each TCLK rising edge. The TAP controller takes precedence over the Queue and must be reset after power up of the device. See TRST description for more details on TAP controller reset. Test-Logic-Reset All test logic is disabled in this controller state enabling the normal operation of the IC. The TAP controller state machine is designed in such a way that, no matter what the initial state of the controller is, the TestLogic-Reset state can be entered by holding TMS at high and pulsing TCK five times. This is the reason why the Test Reset (TRST) pin is optional. Run-Test-Idle In this controller state, the test logic in the IC is active only if certain instructions are present. For example, if an instruction activates the self test, then it will be executed when the controller enters this state. The test logic in the IC is idles otherwise. Select-DR-Scan This is a controller state where the decision to enter the Data Path or the Select-IR-Scan state is made. Select-IR-Scan This is a controller state where the decision to enter the Instruction Path is made. The Controller can return to the Test-Logic-Reset state other wise. Capture-IR In this controller state, the shift register bank in the Instruction Register parallel loads a pattern of fixed values on the rising edge of TCK. The last two significant bits are always required to be “01”. Shift-IR In this controller state, the instruction register gets connected between TDI and TDO, and the captured pattern gets shifted on each rising edge of TCK. The instruction available on the TDI pin is also shifted in to the instruction register. Exit1-IR This is a controller state where a decision to enter either the PauseIR state or Update-IR state is made. Pause-IR This state is provided in order to allow the shifting of instruction register to be temporarily halted. Exit2-DR This is a controller state where a decision to enter either the ShiftIR state or Update-IR state is made. Update-IR In this controller state, the instruction in the instruction register is latched in to the latch bank of the Instruction Register on every falling edge of TCK. This instruction also becomes the current instruction once it is latched. Capture-DR In this controller state, the data is parallel loaded in to the data registers selected by the current instruction on the rising edge of TCK. Shift-DR, Exit1-DR, Pause-DR, Exit2-DR and Update-DR These controller states are similar to the Shift-IR, Exit1-IR, Pause-IR, Exit2-IR and Update-IR states in the Instruction path. 60 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits JTAG INSTRUCTION REGISTER The Instruction register allows instruction to be serially input into the device when the TAP controller is in the Shift-IR state. The instruction is decoded to perform the following: • Select test data registers that may operate while the instruction is current. The other test data registers should not interfere with chip operation and the selected data register. • Define the serial test data register path that is used to shift data between TDI and TDO during data register scanning. The Instruction Register is a 4 bit field (i.e. IR3, IR2, IR1, IR0) to decode 16 different possible instructions. Instructions are decoded as follows. THE INSTRUCTION REGISTER The Instruction register allows an instruction to be shifted in serially into the processor at the rising edge of TCLK. The Instruction is used to select the test to be performed, or the test data register to be accessed, or both. The instruction shifted into the register is latched at the completion of the shifting process when the TAP controller is at UpdateIR state. The instruction register must contain 4 bit instruction register-based cells which can hold instruction data. These mandatory cells are located nearest the serial outputs they are the least significant bits. TEST DATA REGISTER The Test Data register contains three test data registers: the Bypass, the Boundary Scan register and Device ID register. These registers are connected in parallel between a common serial input and a common serial data output. The following sections provide a brief description of each element. For a complete description, refer to the IEEE Standard Test Access Port Specification (IEEE Std. 1149.1-1990). Hex Value 00 01 02 04 0F Instruction Function EXTEST SAMPLE/PRELOAD IDCODE HIGH-IMPEDANCE BYPASS Select Boundary Scan Register Select Boundary Scan Register Select Chip Identification data register JTAG Select Bypass Register JTAG INSTRUCTION REGISTER DECODING TEST BYPASS REGISTER The register is used to allow test data to flow through the device from TDI to TDO. It contains a single stage shift register for a minimum length in serial path. When the bypass register is selected by an instruction, the shift register stage is set to a logic zero on the rising edge of TCLK when the TAP controller is in the Capture-DR state. The operation of the bypass register should not have any effect on the operation of the device in response to the BYPASS instruction. The following sections provide a brief description of each instruction. For a complete description refer to the IEEE Standard Test Access Port Specification (IEEE Std. 1149.1-1990). EXTEST The required EXTEST instruction places the IC into an external boundarytest mode and selects the boundary-scan register to be connected between TDI and TDO. During this instruction, the boundary-scan register is accessed to drive test data off-chip via the boundary outputs and receive test data off-chip via the boundary inputs. As such, the EXTEST instruction is the workhorse of IEEE. Std 1149.1, providing for probe-less testing of solder-joint opens/shorts and of logic cluster function. THE BOUNDARY-SCAN REGISTER The Boundary Scan Register allows serial data TDI be loaded in to or read out of the processor input/output ports. The Boundary Scan Register is a part of the IEEE 1149.1-1990 Standard JTAG Implementation. THE DEVICE IDENTIFICATION REGISTER The Device Identification Register is a Read Only 32-bit register used to specify the manufacturer, part number and version of the processor to be determined through the TAP in response to the IDCODE instruction. IDT JEDEC ID number is 0xB3. This translates to 0x33 when the parity is dropped in the 11-bit Manufacturer ID field. For the IDT72T51546/72T51556, the Part Number field contains the following values: Device IDT72T51546 IDT72T51556 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDCODE The optional IDCODE instruction allows the IC to remain in its functional mode and selects the optional device identification register to be connected between TDI and TDO. The device identification register is a 32-bit shift register containing information regarding the IC manufacturer, device type, and version code. Accessing the device identification register does not interfere with the operation of the IC. Also, access to the device identification register should be immediately available, via a TAP data-scan operation, after power-up of the IC or after the TAP has been reset using the optional TRST pin or by otherwise moving to the Test-Logic-Reset state. Part# Field (HEX) 0x48C 0x48D SAMPLE/PRELOAD The required SAMPLE/PRELOAD instruction allows the IC to remain in a normal functional mode and selects the boundary-scan register to be connected between TDI and TDO. During this instruction, the boundary-scan register can be accessed via a date scan operation, to take a sample of the functional data entering and leaving the IC. This instruction is also used to preload test data into the boundary-scan register before loading an EXTEST instruction. 31(MSB) 28 27 12 11 1 0(LSB) Version (4 bits) Part Number (16-bit) Manufacturer ID (11-bit) 0X0 0X33 1 JTAG DEVICE IDENTIFICATION REGISTER 61 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits HIGH-IMPEDANCE The optional High-Impedance instruction sets all outputs (including two-state as well as three-state types) of an IC to a disabled (high-impedance) state and selects the one-bit bypass register to be connected between TDI and TDO. During this instruction, data can be shifted through the bypass register from TDI to TDO without affecting the condition of the IC outputs. COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES BYPASS The required BYPASS instruction allows the IC to remain in a normal functional mode and selects the one-bit bypass register to be connected between TDI and TDO. The BYPASS instruction allows serial data to be transferred through the IC from TDI to TDO without affecting the operation of the IC. 62 IDT72T51546/72T51556 2.5V, MULTI-QUEUE FLOW-CONTROL DEVICES (32 QUEUES) 36 BIT WIDE CONFIGURATION 1,179,648 and 2,359,296 bits COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES tTCK t4 t1 t2 TCK t3 TDI/ TMS tDS tDH TDO TDO tDO t6 TRST 5998 drw43 Notes to diagram: t1 = tTCKLOW t2 = tTCKHIGH t3 = tTCKFALL t4 = tTCKRISE t5 = tRST (reset pulse width) t6 = tRSR (reset recovery) t5 Figure 38. Standard JTAG Timing JTAG AC ELECTRICAL CHARACTERISTICS (vcc = 2.5V ± 5%; Tcase = 0°C to +85°C) Parameter Symbol Test Conditions Min. SYSTEM INTERFACE PARAMETERS IDT72T51546 IDT72T51556 Parameter Symbol Test Conditions Data Output tDO - 20 ns Data Output Hold tDOH(1) 0 - ns Data Input tDS tDH 10 10 - ns (1) trise=3ns tfall=3ns Min. Max. Units JTAG Clock Input Period tTCK - 100 - ns JTAG Clock HIGH tTCKHIGH - 40 - ns JTAG Clock Low tTCKLOW - 40 - ns JTAG Clock Rise Time tTCKRISE - - 5(1) ns (1) JTAG Clock Fall Time tTCKFALL - - 5 ns JTAG Reset tRST - 50 - ns JTAG Reset Recovery tRSR - 50 - ns NOTE: 1. Guaranteed by design. NOTE: 1. 50pf loading on external output signals. 63 Max. Units ORDERING INFORMATION IDT XXXXX X XX X Device Type Power Speed Package X Process / Temperature Range BLANK I(1) Commercial (0°C to +70°C) Industrial (-40°C to +85°C) BB Plastic Ball Grid Array (PBGA, BB256-1) 5 6 Commercial Only Commercial and Industrial L Low Power 72T51546 72T51556 1,179,648 bits 2.5V Multi-Queue Flow-Control Device 2,359,296 bits 2.5V Multi-Queue Flow-Control Device Clock Cycle Time (tCLK) Speed in Nanoseconds 5998 drw44 NOTE: 1. Industrial temperature range product for the 6ns is available as a standard device. All other speed grades available by special order. DATASHEET DOCUMENT HISTORY 06/06/2003 11/06/2003 pgs. 1 through 64. pgs. 1, 4, 17 and 18. CORPORATE HEADQUARTERS 2975 Stender Way Santa Clara, CA 95054 for SALES: 800-345-7015 or 408-727-6116 fax: 408-492-8674 www.idt.com 64 for Tech Support: 408-330-1533 email: [email protected]