User guide

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 FOP 0 - 16 MHz 1
Clock Period TCP 25 - - nS 2
Clock High TCH 10 - - nS 3
Clock Low TCL 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 TAAS
1 TCP -∆
--nS 4
Address Hold from ALE Low TAAH
1 TCP -∆
- - nS 1, 4
ALE Low to PSEN Low
T
APL
1 TCP -∆
--nS 4
PSEN Low to Data Valid
T
PDA --2 TCP nS 2
Data Hold after PSEN High
T
PDH 0 -1 TCP nS 3
Data Float after PSEN High
T
PDZ 0 -1 TCP nS
ALE Pulse Width TALW
2 TCP -∆
2 T
CP - nS 4
PSEN Pulse Width
T
PSW
3 TCP -∆
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 TCP.
3. Data have been latched internally prior to
PSEN going high.
4. "∆" (due to buffer driving delay and wire loading) is 20 nS.