beautypg.com

7 reload timing, 8 writing a value to counter – FUJITSU MB91460 SERIES FR60 User Manual

Page 870

background image

854

Chapter 41 Up/Down Counter

5.Operation

5.7 Reload Timing

The next time when Up/Down Counter counts down below “0000”, an underflow occurs (an interrupt request is
made) and then reloading is performed.

Note: If clear and reload operations occur at the same time, clear takes precedence.

5.8 Writing a Value to Counter

(1) Counting of Up/Down Counter is disabled.

(2) A value is written to PCR.

(3) “1” is written to the count write bit CTUT.

(4) A value is transferred from the reload/compare register RCR to Up/Down Counter.

Countdown

Reload timing

0066

H

Underflow

0001

H

0066

H

0064

H

0000

H

0065

H

Count value

Compare value

RCR

Up/Down Counter

CSTR

CTUT

(3)

(1)

(4)

(2)

XXH

67 H

67 H

(3)

(1)

(4)

(2)

H

67