CY7C056V
CY7C057V
11
PRELIMINARY
Notes:
27. R/W must be HIGH during all address transitions.
28. A write occurs during the overlap (tSCE or tPWE) of CE0=VIL and CE1=VIH or SEM=VIL and B0–3 LOW.
29. tHA is measured from the earlier of CE0/CE1 or R/W or (SEM or R/W) going HIGH at the end of Write Cycle.
30. If OE is LOW during a R/W controlled write cycle, the write pulse width must be the larger of tPWE or (tHZWE + tSD) to allow the I/O drivers to turn off and data to be placed on
the bus for the required tSD. If OE is HIGH during an R/W controlled write cycle, this requirement does not apply and the write pulse can be as short as the specified tPWE.
31. To access RAM, CE0 = VIL, CE1=SEM = VIH.
32. To access byte B0, CE0 = VIL, B0 = VIL, CE1=SEM = VIH.
To access byte B1, CE0 = VIL, B1 = VIL, CE1=SEM = VIH.
To access byte B2, CE0 = VIL, B2 = VIL, CE1=SEM = VIH.
To access byte B3, CE0 = VIL, B3 = VIL, CE1=SEM = VIH.
33. Transition is measured ±150 mV from steady state with a 5-pF load (including scope and jig). This parameter is sampled and not 100% tested.
34. During this period, the I/O pins are in the output state, and input signals must not be applied.
35. If the CE0 LOW and CE1 HIGH or SEM LOW transition occurs simultaneously with or after the R/W LOW transition, the outputs remain in the high-impedance state.
Switching Waveforms (continued)
tAW
tWC
tPWE
tHD
tSD
tHA
CE0, CE1
R/W
OE
DATA OUT
DATA IN
ADDRESS
tHZOE
tSA
tHZWE
tLZWE
Write Cycle No. 1: R/W Controlled Timing[27, 28, 29, 30]
[33]
[33]
[30]
[31, 32]
NOTE 34
NOTE 34
CHIP SELECT VALID
tAW
tWC
tSCE
tHD
tSD
tHA
R/W
DATA IN
ADDRESS
tSA
Write Cycle No. 2: CE Controlled Timing[27, 28, 29, 35]
CE0, CE1
[31, 32]
CHIP SELECT VALID