UPD17207GF datasheet(45/120 Pages) NEC

Part #	UPD17207GF

Description	4-BIT SINGLE-CHIP MICROCONTROLLER WITH LCD CONTROLLER/DRIVER AND A/D CONVERTER FOR INFRARED REMOTE CONTROL TRANSMITTERS

PDF	120 Pages

Scroll/Zoom	100%

Manufacturer	NEC [NEC]

Direct Link	http://www.nec.com/

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45 / 120 page

µPD17201A, 17207

8.3

WATCHDOG TIMER OPERATION TIMING

Unless the watchdog timer is reset in a fixed time, the WDOUT pin outputs a low level. By connecting the WDOUT

pin to the RESET pin, a program hang-up can be detected by the watchdog timer.

To reset the watchdog timer, set WDTRES (WDTRES = 1).

To disable hang-up detection by the watchdog timer when the subclock is used, program so that WDTRES is set

at intervals of approximately 340 ms or less.

Cautions 1. The watchdog timer cannot be reset in the shaded range in Fig. 8-3. Therefore, set the

watchdog timer before both the fW/2

13 and fW/214 signals go high.

2. For further information on the WDOUT pin, also refer to 14. RESET.

Fig. 8-3

Watchdog Timer Operation Timing

Remark

Figures in the parentheses indicate the value when using the subclock.

fw/2

11 (16Hz)

fw/2

12 (8Hz)

fw/2

13 (4Hz)

fw/2

14 (2Hz)

INTWTM (at 4Hz)

INTWTM (at 16Hz)

WDOUT

Watchdog timer

reset signal

WDTRES

Setting WDTRES is invalid

during this period

WDOUT output goes low if WDTRES is not set

UPD17207GF Datasheet(PDF) 45 Page - NEC