HD64336901G Renesas Technology, HD64336901G Datasheet - Page 209

• Manufacturer Part Number: HD64336901G
• Description: (HD64xxx Series) 16-BIT MICROCONTROLLER
• Manufacturer: Renesas Technology

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 13.1.
13.1
WDT0110A_000020030700
Selectable from nine counter input clocks.
Eight clock sources ( /64, /128, /256, /512, /1024, /2048, /4096, and /8192) or the
WDT dedicated internal oscillator can be selected as the timer-counter clock. When the WDT
dedicated 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.
The watchdog timer is enabled in the initial state.
It starts operating after the reset state is canceled.
Features
internal oscillator
WDT dedicated
[Legend]
TCSRWD: Timer control/status register WD
TCWD:
PSS:
TMWD:
Figure 13.1 Block Diagram of Watchdog Timer
Section 13 Watchdog Timer
Timer counter WD
Prescaler S
Timer mode register WD
CLK
PSS
TCSRWD
TMWD
TCWD
Rev. 1.00, 11/03, page 181 of 376
Internal reset
signal