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Operation, 1 timer mode cms[1:0]=“00 – FUJITSU MB91460 SERIES FR60 User Manual

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Chapter 41 Up/Down Counter

5.Operation

5. Operation

This section describes each operation mode for Up/Down Counter.

5.1 Timer Mode CMS[1:0]=“00”

(1)

An appropriate bit (Reload enable RLDE) is set.

(2)

Up/Down Counter is cleared (“0” is written to CGSC).

(3)

The software activates Up/Down Counter.

(4)

An underflow occurs.

(5)

The reload value is reloaded to Up/Down Counter.

(6)

The software clears the underflow flag.

(7)

The software enables interrupts.

(8)

Up/Down Counter counts down.

(9)

An underflow occurs. (An interrupt request has been made.)

(10)

The software clears the underflow flag.

(11)

Repeat (8) to (10).

CLKS, RLDE

CGSC

CSTR

(1)

(2)

(8)

(7)

(6)

(5)

(4)

(3)

(3)

(9)

(9)

(10)

F

CLKP

divided by 2

F

CLKP

divided by 8

Reload value

Countdown

Interrupt

request

Reload value

Reload value

Interrupt request enabled

Underflow
(Interrupt request)

Cleared by
software

Cleared by
software

Cleared by
software