4571 datasheet(26/126 Pages) RENESAS

Part #	4571

Description	SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

PDF	126 Pages

Scroll/Zoom	100%

Manufacturer	RENESAS [Renesas Technology Corp]

Direct Link	http://www.renesas.com

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26 / 126 page

Rev.1.02

May 25, 2007

Page 26 of 124

REJ03B0179-0102

4571 Group

TIMERS

The 4571 Group has the following timers.

• Programmable timer

The programmable timer has a reload register and enables the

frequency dividing ratio to be set. It is decremented from a

setting value n. When it underflows (count to n + 1), a timer

interrupt request flag is set to “1,” new data is loaded from the

reload register, and count continues (auto-reload function).

• Fixed dividing frequency timer

The fixed dividing frequency timer has the fixed frequency

dividing ratio (n). An interrupt request flag is set to “1” after

every n count of a count pulse.

Fig 30. Auto-reload function

n+1 count

Reload

n+1 count

An interrupt occurs or

a skip instruction is executed.

1st underflow

Reload

2nd underflow

FF16

Time

0016

“1”

“0”

n : Counter initial value

Timer interrupt

request flag

Count starts

4571 Datasheet(PDF) 26 Page - Renesas Technology Corp