21
COMMERCIALTEMPERATURERANGE
IDT723656/723666/723676 CMOS TRIPLE BUS SyncFIFOTM WITH
BUS MATCHING 2,048 x 36 x 2, 4,096 x 36 x 2 and 8,192 x 36 x 2
Figure 9. Serial Programming of the Almost-Full Flag and Almost-Empty Flag Offset Values after Reset (IDT Standard and FWFT Modes)
NOTES:
1. tSKEW1 is the minimum time between the rising CLKA edge and a rising CLKC edge for
FFC/IRC to transition HIGH in the next cycle. If the time between the rising edge of CLKA and rising
edge of CLKC is less than tSKEW1, then
FFC/IRC may transition HIGH one CLKC cycle later than shown.
2. It is not necessary to program Offset register bits on consecutive clock cycles. FIFO write attempts are ignored until
FFA/IRA, FFC/IRC is set HIGH.
3. Programmable offsets are written serially to the SD input in the order
AFA offset (Y1), AEB offset (X1), AFC offset (Y2), and AEA offset (X2).
NOTES:
1. tSKEW1 is the minimum time between the rising CLKA edge and a rising CLKC edge for
FFC/IRC to transition HIGH in the next cycle. If the time between the rising edge of CLKA and rising
edge of CLKC is less than tSKEW1, then
FFC/IRC may transition HIGH one CLKC cycle later than shown.
2.
CSA = LOW, W/RA = HIGH, MBA = LOW. It is not necessary to program Offset register on consecutive clock cycles.
Figure 8. Parallel Programming of the Almost-Full Flag and Almost-Empty Flag Offset Values after Reset (IDT Standard and FWFT Modes)
5611 drw 09
CLKA
MRS1,
MRS2
FFA/IRA
CLKC
FFC/IRC
A0-A35
FS1,FS0
ENA
tFSH
tWFF
tENH
tENS2
tSKEW1
tDS
tDH
tWFF
4
0,0
AFA Offset
(Y1)
AEB Offset
(X1)
AFC Offset
(Y2)
AEA Offset
(X2)
First Word to FIFO1
1
2
(1)
tFSH
tFSS
FS2
CLKA
FFA/IRA
tSENS
tSENH
FS0/SD(3)
tSPH
tSENS
tSENH
tFSS
tWFF
FS1/SEN
AEA Offset
(X2) LSB
tSDS
tSDH
tSDS
tSDH
AFA Offset
(Y1) MSB
MRS1,
MRS2
4
5611 drw 10
tFSS
tFSH
CLKC
4
FS2
FFC/IRC
tWFF
tSKEW(1)