Datasheet

&3,
Data Sheet 74 1999-07

AC Characteristics

CLKOUT and READY
(Standard Supply Voltage Range)
(Operating Conditions apply)
Parameter Symbol Max. CPU Clock
= 25 MHz
Variable CPU Clock
1 / 2TCL = 1 to 25 MHz
Unit
min. max. min. max.
CLKOUT cycle time
W
29
CC 40 40 2TCL 2TCL ns
CLKOUT high time
W
30
CC 14 – TCL – 6 – ns
CLKOUT low time
W
31
CC 10 – TCL – 10 – ns
CLKOUT rise time
W
32
CC–4–4ns
CLKOUT fall time
W
33
CC–4–4ns
CLKOUT rising edge to
ALE falling edge
W
34
CC 0 +

W
A
10 +

W
A
0 +

W
A
10 +

W
A
ns
Synchronous READY
setup time to CLKOUT
W
35
SR 14 – 14 – ns
Synchronous READY
hold time after CLKOUT
W
36
SR4–4–ns
Asynchronous READY
low time
W
37
SR 54 – 2TCL + W
58
–ns
Asynchronous READY
setup time
1)
1) These timings are given for test purposes only, in order to assure recognition at a specific clock edge.
W
58
SR 14 – 14 – ns
Asynchronous READY
hold time
1)
W
59
SR4–4–ns
Async. READY
hold time
after RD
, WR high
(Demultiplexed Bus)
2)
2) Demultiplexed bus is the worst case. For multiplexed bus 2TCL are to be added to the maximum values. This
adds even more time for deactivating READY
.
The 2
W
A
and W
C
refer to the next following bus cycle,W
F
refers to the current bus cycle.
The maximum limit for
W
60
must be fulfilled if the next following bus cycle is READY controlled.
W
60
SR 0 0
+ 2
W
A
+
W
C
+ W
F
2)
0 TCL - 20
+ 2
W
A
+ W
C
+
W
F
2)
ns