HD64F36022 datasheet(193/384 Pages) RENESAS

Part #	HD64F36022

Description	Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Tiny Series

PDF	384 Pages

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Manufacturer	RENESAS [Renesas Technology Corp]

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Section 12 Watchdog Timer

WDT0110A_000020020200

Rev. 4.00 Sep. 23, 2005 Page 167 of 354

REJ09B0025-0400

Section 12 Watchdog Timer

The watchdog timer is an 8-bit timer that can generate an internal reset signal for this LSI if a

system crash prevents the CPU from writing to the timer counter, thus allowing it to overflow.

The block diagram of the watchdog timer is shown in figure 12.1.

Internal reset

signal

PSS

TCWD

TMWD

TCSRWD

Legend:

TCSRWD: Timer control/status register WD

TCWD:

Timer counter WD

PSS:

Prescaler S

TMWD:

Timer mode register WD

Internal

oscillator

CLK

Figure 12.1 Block Diagram of Watchdog Timer

12.1

Features

• Selectable from nine counter input clocks.

Eight clock sources (

φ/64, φ/128, φ/256, φ/512, φ/1024, φ/2048, φ/4096, and φ/8192) or the

internal oscillator can be selected as the timer-counter clock. When the internal oscillator is

selected, it can operate as the watchdog timer in any operating mode.

• Reset signal generated on counter overflow

An overflow period of 1 to 256 times the selected clock can be set.

HD64F36022 Datasheet(PDF) 193 Page - Renesas Technology Corp