FEATURES Fast Cycle Times: 25/30/35 36-bit FIFO Buffers Full 36-bit Wo

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FEATURES Fast Cycle Times: 25/30/35 36-bit FIFO Buffers Full 36-bit Wo

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LH5420
FEATURES Fast Cycle Times: 25/30/35 36-bit FIFO Buffers Full 36-bit Word Width Selectable 36/18/9-bit Word Width Port Independently-Synchronized (`Fully Asynchronous') Operation Port Port `Synchronous' Enable-Plus-Clock Control Both Ports R/W, Enable, Request, Address Control Inputs Sampled Rising Clock Edge Synchronous Request/Acknowledge `Handshake' Capability; Optional Device Comes Into Known Default State Reset; Programming Allowed, Required Asynchronous Output Enables Five Status Flags Port: Full, Almost-Full, Half-Full, Almost-Empty, Empty Almost-Full Flag Almost-Empty Flag Programmable Mailbox Registers with Synchronized Flags Data-Bypass Function Data-Retransmit Function Automatic Byte Parity Checking
PQFP-to-PGA conversion thru-hole board designs, Sharp recommends Pomona Electronics' SMT/PGA Generic Converter model #5853®. This converter maps LH543620 132pin PQFP generic 132-pin (100-mil pitch). more information, contact Sharp Pomona Electronics 1500 East Ninth Street, Pomona, 91766, (909) 469-2900.
Bidirectional FIFO
TTL/CMOS-Compatible Space-Saving PQFP Package PQFP Package Conversion FUNCTIONAL DESCRIPTION
LH5420 contains FIFO buffers, FIFO FIFO These operate parallel, opposite directions, bidirectional data buffering. FIFO FIFO each organized words bits. LH5420 ideal either wide unidirectional applications bidirectional data applications; component count board area reduced. LH5420 36-bit ports, Port Port Each port port-synchronous clock, ports operate asynchronously relative each other. Data flow initiated port rising edge appropriate clock; gated corresponding edgesampled enable, request, read/write control signals. maximum operating frequency, clock duty cycle vary from 60%. lower frequencies, clock waveform quite asymmetric, long minimum pulse-width conditions clock-HIGH clock-LOW remain satisfied; LH5420 fully-static part. Conceptually, port clocks freerunning, periodic `clock' waveforms, used control other signals which edge-sampled. However, there actually absolute requirement that these `clock' waveforms must periodic. `asynchronous' mode operation possible, both directions, independently, appropriate enable request inputs continuously asserted, enough aperiodic `clock' pulses suitable duration generated external logic cause necessary actions occur. synchronous request/acknowledge handshake facility provided each port FIFO data access. This request/ acknowledge handshake resolves FIFO full empty boundary conditions, when ports operated asynchronously relative each other. FIFO status flags monitor extent which each FIFO buffer been filled. Full, Almost-Full, Half-Full, Almost-Empty, Empty flags included each FIFO. Almost-Full Almost-Empty flags programmable over entire FIFO depth, automatically initialized eight locations from respective FIFO boundaries reset. data block fewer words retransmitted desired number times. mailbox registers provide separate path passing control words status words between ports.
6-208
Bidirectional FIFO
LH5420 tion configuration information directly, from peripheral device Port during system startup. word-width-select option provided Port 36-bit, 18-bit, 9-bit data access. This feature allows word-width matching between Port Port with additional logic needed. also ensures maximum utilization bandwidths. Byte Parity Check Flag each port monitors data integrity. Control-Register (zero) selects parity mode, even. This initialized odddata parity reset; reprogrammed even parity, back again parity, desired.
FUNCTIONAL DESCRIPTION (cont'd)
Each mailbox New-Mail-Alert Flag, which synchronized reading port's clock. This mailbox function facilitates synchronization data transfers between asynchronous systems. Data-bypass mode allows Port directly transfer data from Port reset. this mode, device acts registered transceiver under control Port instance, master processor Port data bypass feature send receive initializa-
CONNECTIONS
VCCA D10A VSSA VCCA VSSA VSSB VCCB VSSB D10B D11B VCCB
D11A D12A D13A D14A VSSA D15A D16A D17A R/WA REQA ACKA MBF2 D18A D19A VSSA D20A D21A D22A D23A
CHAMFERED EDGE
VIEW
VCCA D24A D25A D26A VSSA D27A D28A D29A VCCA D30A D31A D32A VSSA D33A D34A D35A D35B D34B VSSB D33B D32B D31B VCCB D30B D29B D28B VSSB D27B D26B D25B VCCB
D12B D13B D14B D15B VSSB D16B D17B MBF1 ACKB REQB R/WB D18B D19B D20B VSSB D21B D22B D23B D24B
5420-30
Figure Connections 132-Pin PQFP Package (TOP VIEW) 6-209
LH5420
Bidirectional FIFO
LIST
SIGNAL NAME PQFP SIGNAL NAME PQFP SIGNAL NAME PQFP
D17A D16A D15A D14A D13A D12A D11A D10A D10B D11B D12B D13B D14B D15B
D16B D17B MBF1 ACKB REQB R/WB D18B D19B D20B D21B D22B D23B D24B D25B D26B D27B D28B D29B D30B D31B D32B D33B D34B D35B D35A D34A D33A D32A D31A D30A D29A
D28A D27A D26A D25A D24A D23A D22A D21A D20A D19A D18A MBF2 ACKA REQA R/WA VSSA VCCA VSSA VCCA VSSA VSSB VCCB VSSB VCCB VSSB VSSB VCCB VSSB VCCB VSSB VSSA VCCA VSSA VCCA VSSA
6-210
Bidirectional FIFO
LH5420
WRITE PORT
FIFO
READ PORT
READ
FIFO
WRITE
PORT CONTROL
PORT CONTROL
5420-36
Figure Simplified LH5420 Block Diagram
BYPASS MBF1 MBF2 MAILBOX REGISTER FIFO MEMORY ARRAY PORT SYNCHRONOUS CONTROL LOGIC PORT SYNCHRONOUS CONTROL LOGIC R/WB REQB ACKB FIXED PROGRAMMABLE STATUS FLAGS RESET LOGIC MAILBOX REGISTER
COMMAND PORT REGISTER
COMMAND PORT REGISTER
R/WA REQA ACKA
WRITE POINTER
READ POINTER
FIXED PROGRAMMABLE STATUS FLAGS
D35A
READ POINTER PORT
WRITE POINTER PORT
D35B WS0,
FIFO MEMORY ARRAY PARITY CHECKING RESOURCE REGISTERS PARITY CHECKING
5420-6
Figure Detailed LH5420 Block Diagram
6-211
LH5420
Bidirectional FIFO
DESCRIPTIONS
TYPE DESCRIPTION
GENERAL VCC, Power, Ground Reset PORT R/WA A0A, A1A, REQA D35A MBF2 ACKA R/WB WS0, REQB D35B MBF1 ACKB I/O/Z I/O/Z Port Free-Running Clock Port Edge-Sampled Read/Write Control Port Edge-Sampled Enable Port Edge-Sampled Address Pins Port Level-Sensitive Output Enable Port Request/Enable FIFO Retransmit Port Bidirectional Data FIFO Full Flag (Write Boundary) FIFO Programmable Almost-Full Flag (Write Boundary) FIFO Half-Full Flag FIFO Programmable Almost-Empty Flag (Read Boundary) FIFO Empty Flag (Read Boundary) New-Mail-Alert Flag Mailbox Port Parity Flag Port Acknowledge PORT Port Free-Running Clock Port Edge-Sampled Read/Write Control Port Edge-Sampled Enable Port Edge-Sampled Address Port Level-Sensitive Output Enable Port Word-Width Select Port Request/Enable FIFO Retransmit Port Bidirectional Data FIFO Full Flag (Write Boundary) FIFO Programmable Almost-Full Flag (Write Boundary) FIFO Half-Full Flag FIFO Programmable Almost-Empty Flag (Read Boundary) FIFO Empty Flag (Read Boundary) New-Mail-Alert Flag Mailbox Port Parity Flag Port Acknowledge
Input, Output, High-Impedance, Power Voltage Level
6-212
Bidirectional FIFO
LH5420
ABSOLUTE MAXIMUM RATINGS
PARAMETER RATING
Supply Voltage Potential Signal Voltage Potential Output Current Storage Temperature Range Power Dissipation (Package Limit)
-0.5 -0.5 -65oC Watts (Quad Flat Pack)
NOTES: Stresses greater than those listed under `Absolute Maximum Ratings' cause permanent damage device. This stress rating transient conditions only. Functional operation device these other conditions outside those indicated `Operating Range' this specification implied. Exposure absolute maximum rating conditions extended periods affect reliability. Outputs should shorted more than seconds. more than output should shorted time. Negative undershoot amplitude permitted once cycle.
OPERATING RANGE
SYMBOL PARAMETER UNIT
Temperature, Ambient Supply Voltage Supply Voltage Logic Input Voltage Logic HIGH Input Voltage
-0.5
NOTE: Negative undershoot amplitude permitted once cycle.
ELECTRICAL CHARACTERISTICS (Over Operating Range)
SYMBOL PARAMETER TEST CONDITIONS UNIT
ICC2 ICC3
Input Leakage Current Leakage Current Logic Output Voltage Logic HIGH Output Voltage Average Supply Current Average Standby Supply Current Power-Down Supply Current
VIH, VOUT -2.0 Measured Inputs VIHMIN (Clock idle) Inputs (Clock idle)
NOTE: ICC, ICC2, ICC3 dependent upon actual output loading, also dependent cycle rates. Specified values with outputs open; and, operating minimum cycle times.
6-213
LH5420
Bidirectional FIFO
TEST CONDITIONS
PARAMETER RATING
Input Pulse Levels Input Rise Fall Times (10% 90%) Output Reference Levels Input Timing Reference Levels Output Load, Timing Tests
Figure
DEVICE UNDER TEST
CAPACITANCE
PARAMETER RATING
INCLUDES SCOPE CAPACITANCES
Figure Output Load Circuit
5420-7
(Input Capacitance) COUT (Output Capacitance)
NOTES: Sample tested only. Capacitances maximum values 25oC, measured MHz, with
6-214
Bidirectional FIFO
LH5420
ELECTRICAL CHARACTERISTICS (VCC 10%, 70°C)
SYMBOL DECRIPTION UNITS
tRWS tRWH tRQS tRQH tACK tMBF tRSS tRSH tFRL tFWL
Clock Cycle Frequency Clock Cycle Time Clock HIGH Time Clock Time Data Setup Time Data Hold Time Enable Setup Time Enable Hold Time Read/Write Setup Time Read/Write Hold Time Request Setup Time Request Hold Time Address Setup Time Address Hold Time
40/25
52/30
65/35
28.5
Data Output Access Time Acknowledge Access Time Output Hold Time Output Enable Time, Low-Z Output Disable Time, HIGH High-Z Clock Flag Valid (Empty Flag) Clock Flag Valid (Full Flag) Clock Flag Valid (Half-Full) Clock Flag Valid (Almost-Empty) Clock Flag Valid (Almost-Full) Clock Flag Valid (Mailbox Flag) Data Parity Flag Valid Reset/Retransmit Pulse Width Reset/Retransmit Setup Time Reset/Retransmit Hold Time Reset Flag Valid First Read Latency First Write Latency Bypass Data Setup Bypass Data Hold Bypass Data Access
NOTES: Timing measurements performed Test Condition' levels. Values guaranteed design; currently production tested. and/or need unless rising edge occurs while being asserted, else rising edge occurs while being asserted. minimum first-write-to-first-read delay, following empty condition, which required assure valid read data. minimum first-read-to-first-write delay, following full condtion, which required assure successful writing data. address setup times hold times need only satisfied clock edges which occur while corresponding enables being asserted. First number used only when enabled; tRSS RSH. REQ/ACK facility available cycle times less than
6-215
LH5420
Bidirectional FIFO Table Resource-Register Addresses
RESOURCE PORT
OPERATIONAL DESCRIPTION
Reset device reset whenever asynchronous Reset (RS) input taken LOW, least rising edge falling edge both occur while LOW. reset operation required after power-up, before first write operation occur. LH5420 fully ready operation after being reset. device programming required default states described below acceptable. reset operation initializes read-address write-address pointers FIFO FIFO those FIFO's first physical memory locations. respective outputs enabled, initial contents these first locations appear outputs. FIFO mailbox status flags updated indicate empty condition. addition, programmable-status-flag offset values initialized eight. Thus, AE1/AE2 flags asserted within eight locations empty condition, AF1/AF2 flags likewise asserted within eight locations full condition, FIFO #1/FIFO respectively. Bypass Operation During reset (whenever LOW) device acts registered transceiver, bypassing internal FIFO memories. Port acts master port. write read operation Port during reset transfers data directly from Port Port considered slave, cannot perform write read operations independently during reset. direction bypass data transmission determined R/WA control input, which does overridden input. Here, `write' operation means passing data from Port Port `read' operation means passing data from Port Port bypass capability used pass initialization configuration data directly between master processor peripheral device during reset. Address Modes Address pins select device resource accessed each port. Port three resource-register-select inputs, A0A, A1A, A2A, which select between FIFO access, mailbox-register access, Control-Register access (write only), Programmable Flag-Offset-Register access. Port single address input, A0B, select between FIFO access mailbox-register access. status resource-register-select inputs sampled rising edge enabled clock (CKA Resource-register select-input address definitions summarized Table
FIFO Mailbox AF2, AE2, AF1, Flag Offsets Register (36-Bit Mode) Control Register (Parity Mode) Flag Offset Register Flag Offset Register Flag Offset Register Flag Offset Register
RESOURCE PORT
FIFO Write
FIFO Mailbox
Port writes FIFO Port writes FIFO write operation initiated rising edge clock (CKA CKB) whenever: appropriate enable (ENA ENB) held HIGH; appropriate request (REQA REQB) held HIGH; appropriate Read/Write control (R/WA R/WB) held LOW; FIFO address selected address inputs (A2A A0B); prescribed setup times hold times observed these signals. Setup times hold times must also observed data-bus pins (D0A D35A D35B). Normally, appropriate Output Enable signal (OEA OEB) HIGH, disable outputs that port, that data word present from external sources gets stored. However, `loopback' mode operation also possible, which data word supplied outputs internal FIFO `turned around' port read back into other FIFO. this mode, outputs port disabled. remain within specification timing parameters, Clock Cycle Frequency must reduced slightly below value which otherwise would permissible that speed grade LH5420. When FIFO full condition reached, write operations locked out. Following first read operation from full FIFO, another memory location freed corresponding Full Flag deasserted HIGH). first write operation should begin earlier than First Write Latency (tFWL) after first read operation from full FIFO, ensure that correct read data retrieved.
6-216
Bidirectional FIFO
LH5420 Almost-Full Flag deasserted following falling clock edge read operation full FIFO. Almost-Empty Flag asserted following rising clock edge read operation that empties FIFO. Almost-Empty Flag deasserted following falling clock edge write operation empty FIFO. Flag offsets written read through Port data bus. four programmable FIFO status flag offsets simultaneously through single 36-bit status word; each programmable flag offset individually, through four eight-bit status words. Table illustrates data format flag-programming words, Table defines meaning each five flags. WARNING: Control inputs which affect computation flag values port generally should change while clock that port HIGH, since some updating flag values takes place falling edge clock. Mailbox Operation mailbox registers provided passing system hardware software control/status words between ports. Each port read mailbox write other port's mailbox. Mailbox access performed rising edge controlling FIFO's clock, with mailbox address selected enable (ENA ENB) HIGH. That writing Mailbox Register reading from Mailbox Register synchronized CKA; writing Mailbox Register reading from Mailbox Register synchronized CKB. R/WA/B OEA/B pins control direction availability mailbox-register accesses. Each mailbox register New-Mail-Alert Flag (MBF1 MBF2), which synchronized reading port's clock. These New-Mail-Alert Flags status indicators only, cannot inhibit mailbox-register read write operations. Request/Acknowledge Handshake Synchronous, request/acknowledge handshake feature provided each port, perform boundary synchronization between asynchronously-operated ports. operates only during normal FIFO operation that port. this feature optional. When used, Request input (REQA/B) sampled rising clock edge. With REQA/B HIGH, R/WA/B determines whether FIFO read operation FIFO write operation being requested. Acknowledge output (ACKA/B) updated during following clock cycle(s). ACKA/B meets setup hold time requirements Enable input (ENA ENB). Therefore, ACKA/B tied back enable input directly gate FIFO accesses, slight decrease maximum operating frequency. assertion ACKA/B signifies that REQA/B asserted. However, ACKA/B does depend logically ENA/B; thus assertion ACKA/B does prove that FIFO write access FIFO read access actually took place. While REQA/B ENA/B being held
OPERATIONAL DESCRIPTION (cont'd)
FIFO Read Port reads from FIFO Port reads from FIFO read operation initiated rising edge clock (CKA CKB) whenever: appropriate enable (ENA ENB) held HIGH; appropriate request (REQA REQB) held HIGH; appropriate Read/Write control (R/WA R/WB) held HIGH; FIFO address selected address inputs (A2A A0B); prescribed setup times hold times observed these signals. Read data becomes valid data-bus pins (D0A D35A D35B) time after rising clock (CKA edge, provided that data outputs enabled. assertive-LOW, asynchronous, Output Enable control input signals. Their effect only enable disable output drivers respective port. Disabling outputs does disable read operation; data transmitted corresponding output register will remain available later, when outputs again enabled, unless subsequently overwritten. When empty condition reached, read operations locked until valid write operation(s) loaded additional data into FIFO. Following first write empty FIFO, corresponding empty flag (EF) will deasserted (HIGH). first read operation should begin earlier than First Read Latency (tFRL) after first write empty FIFO, ensure that correct read data words retrieved. Dedicated FIFO Status Flags dedicated FIFO status flags included Full (FF1 FF2), Half-Full (HF1 HF2), Empty (EF1 EF2). FF1, HF1, indicate status FIFO FF2, HF2, indicate status FIFO Full Flag asserted following rising clock edge write operation that fills FIFO. Full Flag deasserted following falling clock edge read operation full FIFO. Half-Full Flag updated following rising clock edge read write operation FIFO. Empty Flag asserted following rising clock edge read operation that empties FIFO. Empty Flag deasserted following falling clock edge write operation empty FIFO. Programmable Status Flags Four programmable FIFO status flags provided, Almost-Full (AF1 AF2), AlmostEmpty (AE1 AE2). Thus, each port programmable flags monitor status internal FIFO buffer memories. offset values these flags initialized eight locations from respective FIFO boundaries during reset, reprogrammed over entire FIFO depth. Almost-Full Flag asserted following rising clock edge write operation that fills FIFO.
6-217
LH5420
Bidirectional FIFO respectively. inputs parity-evaluation logic come directly (via isolation transistors) from data-bus bonding pads, each case. four bytes 36-bit data word grouped D17, D26, D35. parity each nine-bit byte individually checked, four singlebit parity indications logically inclusive-ORed produce Parity-Flag output. Parity checking initialized parity reset, reprogrammed even parity parity during operation. Control-Register (zero) selects parity mode, even (see Table nine bits each byte treated alike parity logic. byte parity over nine bits compared with Parity Mode Control Register, generate byte-parity-error indication. Then, four byte-parityerror signals NORed together, compute assertive-LOW parity-flag value. Word-Width Selection Port word width data access Port selected control inputs. both tied HIGH 36-bit access; they both tied single-byte access. double-byte access, tied HIGH tied LOW. single-byte-access double-byte-access modes, FIFO write operations Port essentially pack data form 36-bit words, viewed from Port Similarly, single-byte double-byte FIFO read operations Port essentially unpack 36-bit words through series shift operations. FIFO status flags updated following last access which forms complete 36-bit transfer. Since values each status flag computed logic directly associated with FIFO-memory arrays, logic associated with Port flag values reflect array fullness situation terms complete 36-bit words, terms bytes double bytes. However, there such restriction switching from writing reading, from reading writing, Port long tRWS, tDS, satisfied, R/WB change state after single-byte double-byte access, only after full 36-bit-word access. Also, word-width-writing feature continues operate properly `loopback' mode. Note that programmable word-width-matching feature only supported FIFO accesses. Mailbox Data Bypass operations support word-width matching between Port Port Tables Figures summarize word-width selection Port Table Port Word-Width Selection
PORT DATA WIDTH
OPERATIONAL DESCRIPTION (cont'd)
HIGH, ACKA/B considered synchronous, predictive boundary flag. That ACKA/B acts synchronized predictor Almost-Full Flag write operations, synchronized predictor AlmostEmpty Flag read operations. Outside `almost-full' region `almost-empty' region, ACKA/B remains continuously HIGH whenever REQA/B held continuously HIGH. Within `almost-full' region `almost-empty' region, ACKA/B occurs only every third cycle. Assuming that ACKA/B being used control A/B, this repetition-rate decrease help prevent overrun FIFO's actual full empty boundaries, ensure that tFWL (first write latency) tFRL (first read latency) specifications satisfied before ACKA/B received. `almost-full region' defined `that region, where Almost-Full Flag being asserted'; `almostempty region' `that region, where Almost-Empty Flag being asserted.' Thus, extent these `almost' regions depends system programmed offset values Almost-Full Flags AlmostEmpty Flags. system programmed them, then these offset values remain their default values, eight each case. write attempt unsuccessful because corresponding FIFO full, read attempt unsuccessful because corresponding FIFO empty, ACKA/B asserted response REQA/B. REQ/ACK handshake used, then REQA/B input used second enable input, possible minor loss maximum operating speed. this case, ACKA/B output ignored. WARNING: Whether REQ/ACK handshake being used, REQA/B input port must asserted corresponding FIFO operate. Data Retransmit retransmit operation resets read-address pointer corresponding FIFO back first FIFO physical memory location, that data reread. write pointer affected. status flags updated; block data words, which previously been written into read from FIFO, retrieved. block retransmitted bounded first FIFO memory location, FIFO memory location addressed write pointer. FIFO retransmit initiated strobing LOW. FIFO retransmit initiated strobing LOW. Read write operations FIFO should stopped while corresponding Retransmit signal being asserted. Parity Check Parity Check Flags, PFB, asserted (LOW) whenever there parity error data word present Port data Port data
36-Bit (Reserved) 18-Bit 9-Bit
6-218
Bidirectional FIFO Table Resource-Register Programming
RESOURCEREGISTER ADDRESS D35A RESOURCE-REGISTER CONTENTS
LH5420
NORMAL FIFO OPERATION
MAILBOX D35A
AF2, AE2, AF1, FLAG OFFSETS REGISTER (36-BIT MODE) D35A D34A D27A D26A D25A D18A D17A D16A
Offset
Offset
Offset
Offset
CONTROL REGISTER (WRITE-ONLY) PARITY D35A
8-BIT FLAG OFFSET REGISTER D35A
Parity Mode
8-BIT FLAG OFFSET REGISTER D35A
Offset
8-BIT FLAG OFFSET REGISTER D35A
Offset
8-BIT FLAG OFFSET REGISTER D35A
Offset
Offset
NOTES: four programmable-flag-offset values initialized eight during reset operation. parity HIGH; even parity LOW. parity mode initialized during reset operation.
Table Flag Definition Table
FLAG VALID FULL-WORD READ CYCLES REMAINING FLAG FLAG HIGH VALID FULL-WORD WRITE CYCLES REMAINING FLAG FLAG HIGH
256-p
255-p
256-q
255-q
NOTE: Programmable-Almost-Empty offset value. (Default value: Programmable-Almost-Full offset value. (Default value:
6-219
LH5420
Bidirectional FIFO
PORT WORD-WIDTH SELECTION
36-Bit Data Stream D35A D18A Bits 18-35 (2nd Halfword)
18-Bit Data Streams D35B Halfword, then Halfword D18B
Bits 18-35 alfw
PORT
D17A Bits 0-17 (1st Halfword)
ord) Bits Halfw (1st
PORT
D17B
5420-32
Halfword, then Halfword
Figure 36-to-18 Funneling Through FIFO
36-Bit Data Stream D35A D27A Bits 27-35 (4th Byte)
9-Bit Data Streams D35B D27B Byte, then Byte, then Byte, then Byte
D26A D18A
Bits 18-26 (3rd Byte)
D26B D18B Byte, then Byte, then Byte, then Byte
PORT
D17A Bits 9-17 (2nd Byte) D17B
PORT
Byte, then Byte, then Byte, then Byte
Bits (1st Byte)
5420-34
Byte, then Byte, then Byte, then Byte
Figure 36-to-9 Funneling Through FIFO
NOTES: heavy black borders register segments indicate main data path, suitable most applications. Alternate paths feature different ordering bytes within word, Port funneling process does change ordering bits within byte. Halfwords (Figure bytes (Figure transferred parallel form from Port Port
word-width setting changed during system operation; however, clock intervals should allowed these signals settle, before again attempting read D35B, three dummy words should passed through initially. Also, incomplete data words occur when word width changed from shorter longer, inappropriate point data block passing through FIFO. avoid such incomplete data words, achieve proper synchronization, `dummy' partial words should supplied complete final longer word.
6-220
Bidirectional FIFO
LH5420
PORT WORD-WIDTH SELECTION
36-Bit Data Stream D35A D18A
18-Bit Data Stream D35B
Bits 18-35 alfw
D18B
PORT
D17A Bits 0-17 (1st Halfword) D17B
PORT
Halfword, then Halfword
5420-33
Figure 18-to-36 Defunneling Through FIFO
36-Bit Data Stream D35A D27A Bits 27-35 (4th Byte)
9-Bit Data Stream D35B D27B
D26A D18A Bits 18-26 (3rd Byte)
D26B
D18B
PORT
D17A Bits 9-17 (2nd Byte) D17B
PORT
Bits (1st Byte)
Byte, then Byte, then Byte, then Byte
5420-35
Figure 9-to-36 Defunneling Through FIFO
NOTES: heavy black borders register segments indicate only data paths used. other byte segments Port participate data path during defunneling. defunneling process does change ordering bits within byte. Halfwords (Figure bytes (Figure transferred parallel form from Port Port
word-width setting changed during system operation; however, clock intervals should allowed these signals settle, before again attempting send data, three dummy words should passed through initially. Also, incomplete data words occur when word width changed from shorter longer, inappropriate point data block passing through FIFO. avoid such incomplete data words, achieve proper synchronization, `dummy' partial words should supplied complete final longer word.
6-221
LH5420
Bidirectional FIFO
TIMING DIAGRAMS
NOTES: overrides other input signals, except R/WA, operates asynchronously. operates whether and/or asserted. tRSS, tRSH need unless rising edge and/or occurs while that clock enabled. parity check initialized byte parity reset. flag offsets initialized eight locations from boundary reset.
5420-26
Figure Reset Timing
6-222
Bidirectional FIFO
LH5420
TIMING DIAGRAMS (cont'd)
tRWS tRWS
R/WA
D35B
BYPASS
BYPASS DATA
D35A
PREVIOUS DATA
BYPASS
BYPASS
NOTES: tRSS, tRSH need unless rising edge occurs while that clock enabled. Port considered master port bypass operation. Thus, CKA, R/WA, control transmission data between ports reset.
5420-27
Figure Data Bypass Timing
6-223
LH5420
Bidirectional FIFO
TIMING DIAGRAMS (cont'd)
READ FROM FIFO
WRITE FIFO
tRWS tRWS
R/WA
D35A
PREVIOUS DATA
DATA
DATA
VALID
VALID
VALID
NOTES: Port Parity Error Flag (PFA) reflects parity status data present data bus. status does gate read write operations. left during write operation, then previous data held output latch written back into FIFO
5420-24
Figure Port FIFO Read/Write
6-224
Bidirectional FIFO
LH5420
TIMING DIAGRAMS (cont'd)
READ FROM FIFO
WRITE FIFO
tRWS tRWS
R/WB
D35B
PREVIOUS DATA
DATA
DATA
VALID
VALID
VALID
NOTES: Port Parity Error Flag (PFB) reflects parity status data present data bus. status does gate read write operations. left during write operation, then previous data held output latch written back into FIFO
5420-25
Figure Port FIFO Read/Write
6-225
LH5420
Bidirectional FIFO
TIMING DIAGRAMS (cont'd)
WRITE MAILBOX tRWS tRWS READ FROM MAILBOX
R/WA
MBF2 MAXIMUM CYCLES LATENCY
MBF1
D35A
MAILBOX
MAILBOX
NOTES: Both edges MBF2 synchronized Port clock, CKA. Both edges MBF1 synchronized Port clock, CKB. There maximum clock cycles synchronization latency before MBF1 asserted indicate valid mailbox data. identical, there maximum clock cycle. status mailbox flags does prevent mailbox read write operations.
5420-22
Figure Port Mailbox Access 6-226
Bidirectional FIFO
LH5420
TIMING DIAGRAMS (cont'd)
WRITE MAILBOX tRWS
READ FROM MAILBOX
tRWS
R/WB
MBF1 MAXIMUM CYCLES LATENCY
MBF2
D35B
MAILBOX
MAILBOX
NOTES: Both edges MBF2 synchronized Port clock, CKA. Both edges MBF1 synchronized Port clock, CKB. There maximum clock cycles synchronization latency before MBF2 asserted indicate valid mailbox data. identical, there maximum clock cycle. status mailbox flags does prevent mailbox read write operations.
5420-23
Figure Port Mailbox Access
6-227
LH5420
Bidirectional FIFO
TIMING DIAGRAMS (cont'd)
LOAD FLAG POSITIONS tRWS
READ FLAG POSITIONS
tRWS
R/WA
D35A
FLAG DATA
FLAG DATA
AE1, AE2, AF1, NOTES: valid flag address codes data formats, Table flag status altered flag programming, updated flags will valid within time tRF. Control Register loaded shown here, with A2A, A1A, HLL. However, available reading back.
5420-18
Figure Flag Programming
6-228
Bidirectional FIFO
LH5420
TIMING DIAGRAMS (cont'd)
tRWS
R/WA (R/WB
(EF1)
tRWS
R/WB (R/WA
NOTES: A2A, A1A, held HIGH FIFO access Port held HIGH FIFO access Port Parameters without parentheses apply FIFO operation. Parameters with parentheses apply FIFO operation.
5420-1
Figure Empty Flag Timing
tRWS
R/WA (R/WB
(AE1)
tRWS
R/WB (R/WA
NOTE: A2A, A1A, A0A, held HIGH FIFO access.
5420-2
Figure Almost-Empty Flag Timing 6-229
LH5420
Bidirectional FIFO
TIMING DIAGRAMS (cont'd)
tRWS
R/WA (R/WB
(FF2)
(CKA tRWS
R/WB (R/WA
NOTE: A2A, A1A, A0A, held HIGH FIFO access.
5420-3
Figure Full Flag Timing
tRWS
R/WA (R/WB
(AF2)
tRWS
R/WB (R/WA
NOTE: A2A, A1A, A0A, held HIGH FIFO access.
5420-4
Figure Almost-Full Flag Timing 6-230
Bidirectional FIFO
LH5420
TIMING DIAGRAMS (cont'd)
tRWS
R/WA (R/WB
(HF2)
tRWS
R/WB (R/WA
NOTE: A2A, A1A, A0A, held HIGH FIFO access.
5420-5
Figure Half-Full Flag Timing
tRWS
R/WA
tRWS
R/WB
NOTES: tRSS tRSH need unless rising edge occurs while that clock enabled. tRSS time needed deassert before returning normal FIFO cycle. tRSH time needed before asserting after normal FIFO cycle.
5420-20
Figure FIFO Retransmit 6-231
LH5420
Bidirectional FIFO
TIMING DIAGRAMS (cont'd)
tRWS
R/WB
tRSS
tRWS
R/WA
NOTES: tRSS tRSH need unless rising edge occurs while that clock enabled. tRSS time needed deassert before returning normal FIFO cycle. tRSH time needed before asserting after normal FIFO cycle.
5420-21
Figure FIFO Retransmit
6-232
Bidirectional FIFO
LH5420
TIMING DIAGRAMS (cont'd)
tRWS tRWS
R/WA
D35A
tRWS tRWS
D35B
PREVIOUS DATA
NOTES: A2A, A1A, A0A, held HIGH FIFO access. held HIGH. held LOW. tFRL (First Read Latency) first read following empty condition begin earlier than tFRL after first write empty FIFO, ensure that valid read data retrieved.
5420-16
Figure FIFO Write Read Operation Near-Empty Region
6-233
LH5420
Bidirectional FIFO
TIMING DIAGRAMS (cont'd)
tRWS tRWS
R/WB
D35B
tRWH tRWS tRWH tRWS
D35A
PREVIOUS DATA
NOTES: A2A, A1A, A0A, held HIGH FIFO access. held HIGH. held LOW. tFRL (First Read Latency) first read following empty condition begin earlier than tFRL after first write empty FIFO, ensure that valid read data retrieved.
5420-17
Figure FIFO Write Read Operation Near-Empty Region
6-234
Bidirectional FIFO
LH5420
TIMING DIAGRAMS (cont'd)
tRWS tRWS
R/WA
D35A
tRWS tRWS
D35B
PREVIOUS DATA
NOTES: A2A, A1A, held HIGH FIFO access Port held HIGH FIFO access Port held HIGH. held LOW. tFWL (First Write Latency) first write following full condition begin earlier than tFWL after first read from full FIFO, ensure that valid write data written.
5420-14
Figure FIFO Read Write Operation Near-Full Region
6-235
LH5420
Bidirectional FIFO
TIMING DIAGRAMS (cont'd)
tRWS tRWS
R/WB
D35B
tRWS tRWS
D35A
PREVIOUS DATA
NOTES: A2A, A1A, held HIGH FIFO access Port held HIGH FIFO access Port held LOW. held HIGH. tFWL (First Write Latency) first write following full condition begin earlier than tFWL after first read from full FIFO, ensure that valid write data written.
5420-15
Figure FIFO Read Write Operation Near-Full Region
6-236
Bidirectional FIFO
LH5420
TIMING DIAGRAMS (cont'd)
tRWS
R/WB
D17B
BITS 0-17
BITS 18-35
BITS 0-17
BITS 18-35
BITS 0-17
WORD D18B D35B
BITS 18-35
WORD
BITS 0-17 BITS 18-35
WORD
BITS 0-17 BITS 18-35
WORD NOTES: held HIGH FIFO access. held LOW. held HIGH held double-byte access.
WORD
WORD
5420-13
Figure Port Double-Byte FIFO Read Access 36-to-18 Funneling
tRWS
R/WB
D17B
BITS 0-17
BITS 18-35
BITS 0-17
BITS 18-35
BITS 0-17
BITS 18-35
WORD
WORD
WORD
NOTES: held HIGH FIFO access. held HIGH. held HIGH held double-byte access.
5420-12
Figure Port Double-Byte FIFO Write Access 18-to-36 Defunneling 6-237
LH5420
Bidirectional FIFO
TIMING DIAGRAMS (cont'd)
tRWS
R/WB
BITS
BITS 9-17
BITS 18-26
BITS 27-35
BITS
WORD D17B
BITS 9-17 BITS 18-26 BITS 27-35
WORD
BITS BITS 9-17
WORD D18B D26B
BITS 18-26 BITS 27-35 BITS
WORD
BITS 9-17 BITS 18-26
WORD D27B D35B
BITS 27-35 BITS BITS 9-17
WORD
BITS 18-26 BITS 27-35
WORD NOTES: held HIGH FIFO access. held LOW. both held single-byte access.
WORD
5420-11
Figure Port Single-Byte FIFO Read Access 36-to-9 Funneling
6-238
Bidirectional FIFO
LH5420
TIMING DIAGRAMS (cont'd)
tRWS
R/WB
BITS
BITS 9-17
BITS 18-26
BITS 27-35
BITS
BITS 9-17
WORD NOTES: held HIGH FIFO access. held HIGH. both held single-byte access.
WORD
5420-10
Figure Port Single-Byte FIFO Write Access 9-to-36 Defunneling
Outside 'almost-full' region, Acknowledge continuous continuous Request.
Starting third cycle after entering 'almost-full' region, Acknowledge occurs every third cycle prevent underrun 'full' condition.
(CKB tRWS
R/WA (R/WB
(REQB
(ACKB
(AF2)
NOTES: FIFO access occur, must held HIGH required setup hold times. tied directly directly gate FIFO accesses. Indicates where write would take place, were tied must maintained HIGH throughout entire clock cycle generated. When REQ/ACK handshake used, ignored, tied HIGH used second enable. Parameters without parentheses apply Port Parameters with parentheses apply Port
5420-8
Figure Write Request/Acknowledge Handshake
6-239
LH5420
Bidirectional FIFO
TIMING DIAGRAMS (cont'd)
Outside 'almost-empty' region, Acknowledge continuous continuous Request.
Starting third cycle after entering 'almost-empty' region, Acknowledge occurs every third cycle prevent underrun 'empty' condition.
(CKB tRWS
R/WA (R/WB
(REQB
(ACKB
(AE1) NOTES: FIFO access occur, must held HIGH required setup hold times. tied directly directly gate FIFO accesses. Indicates where read would take place, were tied must maintained HIGH throughout entire clock cycle generated. When REQ/ACK handshake used, ignored, tied HIGH used second enable. Parameters without parentheses apply Port Parameters with parentheses apply Port
5420-9
Figure Read Request/Acknowledge Handshake
6-240
Bidirectional FIFO
LH5420
PACKAGE DIAGRAM
132PQFP (PQFP132-P-S950) SECTION
0.15 [0.006] 0.25 [0.010] TYP.
CHAMFER
0.51 [0.020] MIN.
0.10 [0.004] 0.635 [0.025] NON-ACCUM
28.02 [1.103] 27.86 [1.097] 27.69 [1.090] 27.18 [1.070] 24.21 [0.953] 24.05 [0.947] VIEW
24.21 [0.953] 24.05 [0.947] 27.69 [1.090] 27.18 [1.070] 28.02 [1.103] 27.86 [1.097] MAXIMUM LIMIT MINIMUM LIMIT
0.51 [0.020] MIN. 4.57 [0.180] 4.06 [0.160]
DIMENSIONS [INCHES]
PQFP
132-pin PQFP
6-241
LH5420
Bidirectional FIFO
ORDERING INFORMATION
LH5420 Device Type Package Speed Cycle Times (ns)
132-Pin, Plastic Quad Flat Package (PQFP132-P-S950) Bidirectional FIFO
Example: LH5420P-25 (256 Bidirectional FIFO, 132-Lead, Plastic Quad Flat Package)
5420MD
6-242

FEATURES Fast Cycle Times: 25/30/35 36-bit FIFO Buffers Full 36-bit Wo

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