Switching Waveforms (continued)
Reset Timing [17]
RS
REN, WEN,
LD
EF,PAE
FF,PAF,
HF
Q0 – Q17
tRS
tRSF
tRSF
tRSF
tRSR
First Data Word Latency after Reset with Simultaneous Read and Write
CY7C4255
CY7C4265
[18]
OE=1
OE=0
4255–8
WCLK
tDS
D0 –D17
D0 (FIRSTVALID WRITE)
D1
D2
WEN
tENS
RCLK
tFRL[19]
tSKEW2
tREF
EF
D3
D4
REN
Q0 –Q17
OE
tOLZ
tA
tOE
tA[19]
D0
D1
4255–9
Notes:
17. The clocks (RCLK, WCLK) can be free-running during reset.
18. After reset, the outputs will be LOW if OE = 0 and three-state if OE = 1.
19. When tSKEW2 > minimum specification, tFRL (maximum) = tCLK + tSKEW2. When tSKEW2 < minimum specification, tFRL (maximum) = either 2*tCLK + tSKEW2 or tCLK +
tSKEW2. The Latency Timing applies only at the Empty Boundary (EF = LOW).
20. The first word is available the cycle after EF goes HIGH, always.
Document #: 38-06004 Rev. *B
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