Rainbow Electronics W78C801 User Manual
Page 13
W78C801
Publication Release Date: February 1999
- 13 -
Revision A3
AC CHARACTERISTICS
Clock Input Waveform
T
T
XTAL1
F
CH
CL
OP,
T
CP
PARAMETER
SYMBOL
MIN.
TYP.
MAX.
UNIT
NOTES
Operating Speed
F
OP
0
-
16
MHz
1
Clock Period
T
CP
25
-
-
nS
2
Clock High
T
CH
10
-
-
nS
3
Clock Low
T
CL
10
-
-
nS
3
Notes:
1. The clock may be stopped indefinitely in either state.
2. The T
CP
specification is used as a reference in other specifications.
3. There are no duty cycle requirements on the XTAL1 input.
Program Fetch Cycle
PARAMETER
SYMBOL
MIN.
TYP.
MAX.
UNIT
NOTES
Address Valid to ALE Low
T
AAS
1 T
CP
-
∆
-
-
nS
4
Address Hold from ALE Low
T
AAH
1 T
CP
-
∆
-
-
nS
1, 4
ALE Low to
PSEN Low
T
APL
1 T
CP
-
∆
-
-
nS
4
PSEN Low to Data Valid
T
PDA
-
-
2 T
CP
nS
2
Data Hold after PSEN High
T
PDH
0
-
1 T
CP
nS
3
Data Float after PSEN High
T
PDZ
0
-
1 T
CP
nS
ALE Pulse Width
T
ALW
2 T
CP
-
∆
2 T
CP
-
nS
4
PSEN Pulse Width
T
PSW
3 T
CP
-
∆
3 T
CP
-
nS
4
Notes:
1. P0.0
−P0.7, P2.0−P2.7 remain stable throughout entire memory cycle.
2. Memory access time is 3 T
CP
.
3. Data have been latched internally prior to PSEN going high.
4. "
∆" (due to buffer driving delay and wire loading) is 20 nS.