w78c31b Winbond Electronics Corp America, w78c31b Datasheet - Page 8

• Manufacturer Part Number: w78c31b
• Description: 8-bit Microcontroller
• Manufacturer: Winbond Electronics Corp America

Program Fetch Cycle
Notes:
1. P0.0-P0.7, P2.0-P2.7 remain stable throughout entire memory cycle.
2. Memory access time is 3 T
3. Data have been latched internally prior to PSEN going high.
4. " " ( due to buffer driving delay and wire loading) is 20 nS.
Data Read Cycle
Notes:
1. Data memory access time is 8 T
2. " " (due to buffer driving delay and wire loading) is 20 nS.
Data Write Cycle
Note: " " (due to buffer driving delay and wire loading) is 20 nS.
Port Access Cycle
Address Valid to ALE Low
Address Hold after ALE Low
ALE Low to PSEN Low
PSEN Low to Data Valid
Data Hold after PSEN High
Data Float after PSEN High
ALE Pulse Width
PSEN Pulse Width
ALE Low to RD Low
RD Low to Data Valid
Data Hold after RD High
Data Float after RD High
RD Pulse Width
ALE Low to WR Low
Data Valid to WR Low
Data Hold from WR High
Port Input Setup to ALE Low
Port Input Hold from ALE Low
Port Output to ALE
WR Pulse Width
PARAMETER
PARAMETER
PARAMETER
PARAMETER
CP
.
CP
.
SYMBOL
SYMBOL
SYMBOL
SYMBOL
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
T
DAW
DWD
DWR
PSW
ALW
DDH
DRD
DAD
AAS
AAH
PDA
PDH
PDZ
DAR
DDA
DDZ
PDS
PDH
PDA
APL
- 8 -
2 T
3 T
6 T
6 T
1 T
1 T
1 T
3 T
3 T
1 T
1 T
1 T
1 T
MIN.
MIN.
MIN.
MIN.
0
0
CP
CP
0
0
CP
CP
0
CP-
CP-
CP-
CP-
CP-
CP-
CP-
-
-
CP
CP
-
-
-
-
2 T
3 T
6 T
6 T
TYP.
TYP.
TYP.
TYP.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
CP
CP
CP
CP
3 T
3 T
2 T
1 T
1 T
4 T
2 T
2 T
MAX.
MAX.
MAX.
MAX.
CP+
CP+
-
-
-
-
-
-
-
-
-
-
-
-
CP
CP
CP
CP
CP
CP
W78C31B
UNIT
UNIT
UNIT
UNIT
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
NOTE
NOTE
1, 4
1, 2
S
S
4
2
3
4
4
1
2
4