IDT7203/7204/7205/7206/7207/7208CMOSASYNCHRONOUSFIFO
2,048 x 9, 4,096 x 9, 8,192 x 9, 16,384 x 9, 32,768 x 9, 65,536 x 9
COMMERCIAL,INDUSTRIALANDMILITARY
TEMPERATURERANGES
FIFOpermitsareadingofasinglewordafterwritingonewordofdataintoan
emptyFIFO. The data is enabledonthe bus in(tWEF +tA)ns afterthe rising
edgeofW,calledthefirstwriteedge,anditremainsonthebusuntiltheRline
is raisedfromLOW-to-HIGH,afterwhichthebus wouldgointoathree-state
mode after tRHZ ns. The EF line would have a pulse showing temporary
deassertionandthenwouldbeasserted.
Inthewriteflow-throughmode(Figure18),theFIFOpermitsthewritingof
asinglewordofdataimmediatelyafterreadingonewordofdatafromafullFIFO.
TheRlinecausestheFFtobedeassertedbuttheWlinebeingLOWcauses
ittobeassertedagaininanticipationofanewdataword.Ontherisingedgeof
W, the newwordis loadedinthe FIFO. The Wline mustbe toggledwhenFF
isnotassertedtowritenewdataintheFIFOandtoincrementthewritepointer.
USAGEMODES:
Width Expansion
Wordwidthmaybeincreasedsimplybyconnectingthecorrespondinginput
controlsignalsofmultipledevices. Statusflags(EF,FFandHF)canbedetected
fromanyonedevice. Figure13demonstratesan18-bitwordwidthbyusing
twoIDT7203/7204/7205/7206/7207/7208s. Anywordwidthcanbeattained
by adding additional IDT7203/7204/7205/7206/7207/7208s (Figure 13).
Bidirectional Operation
Applications which require data buffering between two systems (each
system capable of Read and Write operations) can be achieved by pairing
IDT7203/7204/7205/7206/7207/7208s as shown in Figure 16. Both Depth
ExpansionandWidthExpansionmaybeusedinthis mode.
Compound Expansion
Thetwoexpansiontechniquesdescribedabovecanbeappliedtogether
in a straightforward manner to achieve large FIFO arrays (see Figure 15).
Data Flow-Through
Twotypesofflow-throughmodesarepermitted,areadflow-throughand
write flow-through mode. For the read flow-through mode (Figure 17), the
(HALF-FULL FLAG)
WRITE (W)
(HF)
READ (R)
9
IDT
7203
7204
7205
7206
7207
7208
9
DATA IN (D)
FULL FLAG (FF)
RESET (RS)
DATA OUT (Q)
EMPTY FLAG (EF)
RETRANSMIT (RT)
2661 drw14
EXPANSION IN (XI)
Figure 12. Block Diagram of 2,048 x 9, 4,096 x 9, 8,192 x 9, 16,384 x 9, 32,768 x 9, 65,536 x 9 FIFO Used in Single Device Mode
HF
HF
18
9
9
DATA IN (D)
IDT
WRITE (W)
IDT
READ (R)
7203
7204
7205
7206
7207
7208
7203
7204
7205
7206
7207
7208
FULL FLAG (FF)
RESET (RS)
EMPTY FLAG (EF)
RETRANSMIT (RT)
9
9
XI
XI
18
OUT (Q)
DATA
NOTE:
2661 drw15
1. Flag detection is accomplished by monitoring the FF, EF and HF signals on either (any) device used in the width expansion configuration.
Do not connect any output signals together.
Figure 13. Block Diagram of 2,048 x 18, 4,096 x 18, 8,192 x 18, 16,384 x 18, 32,768 x 18, 65,536 x 18 FIFO Memory Used in Width Expansion Mode
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IDT [ INTEGRATED DEVICE TECHNOLOGY ]
