Preliminary W78E51B
Data Write Cycle
PARAMETER
SYMBOL
MIN.
TYP.
MAX.
UNIT
nS
TDAW
-
3 TCP -D
1 TCP -D
1 TCP -D
6 TCP -D
3 TCP +D
ALE Low to WR Low
Data Valid to WR Low
Data Hold from WR High
WR Pulse Width
TDAD
TDWD
TDWR
-
-
-
-
-
nS
nS
6 TCP
nS
Note: "D" (due to buffer driving delay and wire loading) is 20 nS.
Port Access Cycle
PARAMETER
Port Input Setup to ALE Low
Port Input Hold from ALE Low
Port Output to ALE
SYMBOL
TPDS
MIN.
TYP.
MAX.
UNIT
nS
1 TCP
0
-
-
-
-
-
-
TPDH
nS
TPDA
1 TCP
nS
Note: Ports are read during S5P2, and output data becomes available at the end of S6P2. The timing data are referenced to
ALE, since it provides a convenient reference.
Program Operation
PARAMETER
VPP Setup Time
SYMBOL
TVPS
TDS
MIN.
2.0
2.0
2.0
2.0
0
TYP.
MAX.
UNIT
-
-
mS
mS
mS
mS
mS
mS
Data Setup Time
Data Hold Time
-
-
TDH
-
-
Address Setup Time
Address Hold Time
TAS
-
-
-
-
TAH
TPWP
290
300
310
CE Program Pulse Width for
Program Operation
TOCS
TOCH
TOES
2.0
2.0
2.0
-
-
-
-
-
-
mS
mS
mS
nS
OECTRL Setup Time
OECTRL Hold Time
OE Setup Time
TDFP
TOEV
0
-
-
-
130
150
OE High to Output Float
Data Valid from OE
nS
Note: Flash data can be accessed only in flash mode. The RST pin must pull in VIH status, the ALE pin must pull in VIL status, and
the PSEN pin must pull in VIH status.
Publication Release Date: December 1998
- 15 -
Revision A1
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