Sharp MZ-80B Owner's Manual page 89

82
Figures 3.0-SA and 3.0-SB illustrate how a programmable counter can be used to extend inte rrupt acknowledge
time. (Configured as shown to add one wait state)
LAST T
STATE · o~
I
LAST M CYCLE OF
IN STRUCTION
IORQ
74S04
+ 5V
~
IORQ
~Q-~-TE-~-1-P_H_E_R- A L)
B
WAIT
,.-----+--0
7432
Q- (-T_O_C_P_U_ ) _
_ 1.::\
M I - - { ) L : J
EXTENDING INTERRUPT ACKNOWLEDGE TIME WITH WAIT STATE
FIGURE 3 .0-5A
AUTOMATIC
WAIT-\-----~\
USER WAIT
T w
*
T w •
DATA BUS - - - - - - - - - - - - - _ , _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ -+-----~-----~~
WAIT
NORMAL ACKNOWLEDGE
TIME
f.---ACKNOWLEDGE TIME WITH ONE
ADDITIONAL WAIT STATE
-----+
REQUEST/ACKNOWLEDGE CYCLE WITH ONE ADDITIONAL WAIT STATE
FIGURE 3.0·5B