Intel 80C186XL, 80C188XL user manual Timer/Counter Unit, 3.Timers 0 and 1 Flow Chart

Models: 80C186XL 80C188XL

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Figure 9-3. Timers 0 and 1 Flow Chart

TIMER/COUNTER UNIT

 

 

 

Timer

No

 

 

 

Start

 

Enabled

Done

 

 

 

 

 

 

 

(EN = 1)

 

 

 

 

 

 

 

 

 

 

 

?

 

 

 

 

 

 

Yes

 

 

 

 

 

No

External

Yes

 

 

 

 

Clocking

 

 

 

 

 

 

 

 

 

 

 

(EXT = 1)

 

 

 

 

 

 

?

 

 

 

 

No

Retrigger

Yes

 

 

 

 

 

(RTG = 1)

 

 

 

 

 

 

?

 

 

 

 

No

Timer Input

 

Lo to Hi

Yes

Lo to Hi

Yes

 

transition on input

transition on input

 

at High Level

 

pin since last

 

pin since last

 

 

?

 

service

 

service

 

 

 

 

?

 

?

 

 

Yes

 

No

 

No

 

 

Prescaler On

No

 

Clear Count

 

 

 

 

Register

 

 

 

(P = 1)

 

 

 

 

 

 

?

 

 

 

 

 

 

Yes

 

 

Done

 

 

 

 

 

 

 

 

 

Did Timer 2

Yes

Increment

 

 

 

 

Reach Maxcount

 

 

 

 

 

 

 

 

 

 

Counter

 

 

 

 

Last Service

 

 

 

 

 

 

 

 

 

 

 

State

 

 

 

 

 

 

?

 

 

 

 

 

 

No

 

Continued

 

 

 

 

Done

 

 

 

 

 

 

"A"

 

 

 

 

 

 

 

 

A1294-0A

Figure 9-3. Timers 0 and 1 Flow Chart

9-4

Page 233
Image 233
Intel 80C186XL, 80C188XL user manual Timer/Counter Unit, 3.Timers 0 and 1 Flow Chart