Intel 80C188XL - Manual (Page 233)

TIMER/COUNTER UNIT
9-4
Figure 9-3. Timers 0 and 1 Flow Chart
Timer
Enabled
(EN = 1)
?
Clear Count
Register
Start
No
Yes
No
Yes
Lo to Hi
transition on input
pin since last
service
?
Done
External
Clocking
(EXT = 1)
?
Retrigger
(RTG = 1)
?
Yes
No
No
Yes
Yes
Did Timer 2
Reach Maxcount
Last Service
State
?
Prescaler On
(P = 1)
?
Lo to Hi
transition on input
pin since last
service
?
Timer Input
at High Level
?
No
No
Yes
Done
Done
Increment
Counter
Yes
Continued
"A"
No Yes
No
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