hd66100 Renesas Electronics Corporation., hd66100 Datasheet - Page 248

• Manufacturer Part Number: hd66100
• Description: H8/3867 Series
• Manufacturer: Renesas Electronics Corporation.

9.6
9.6.1
The watchdog timer has an 8-bit counter that is incremented by an input clock. If a system
runaway allows the counter value to overflow before being rewritten, the watchdog timer can reset
the chip internally.
1. Features
Features of the watchdog timer are given below.
2. Block diagram
Figure 9.16 shows a block diagram of the watchdog timer.
øw/32
Incremented by internal clock source (ø/8192 or øw/32).
A reset signal is generated when the counter overflows. The overflow period can be set from
from 1 to 256 times 8192/ø or 32/øw (from approximately 4 ms to 1000 ms when ø = 2.00
MHz).
Use of module standby mode enables this module to be placed in standby mode independently
when not used.
ø
Notation:
TCSRW:
TCW:
PSS:
Watchdog Timer
Overview
Timer control/status register W
Timer counter W
Prescaler S
PSS
Figure 9.16 Block Diagram of Watchdog Timer
ø/8192
TCSRW
TCW
Reset signal
233