HD64F36049 datasheet(321/562 Pages) RENESAS

Part #	HD64F36049

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

PDF	562 Pages

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Manufacturer	RENESAS [Renesas Technology Corp]

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Section 15 Watchdog Timer

Rev. 3.00 Mar. 15, 2006 Page 289 of 526

REJ09B0060-0300

Section 15 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 15.1.

Internal reset

signal

PSS

TCWD

TMWD

TCSRWD

[Legend]

TCSRWD:

TCWD:

PSS:

TMWD:

Timer control/status register WD

Timer counter WD

Prescaler S

Timer mode register WD

Internal

oscillator

CLK

Figure 15.1 Block Diagram of Watchdog Timer

15.1

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.

HD64F36049 Datasheet(PDF) 321 Page - Renesas Technology Corp