TMPM330 - Keil

Under development
14. Watchdog Timer (Runaway Detection Timer)
The TMPM330 has a built-in watchdog timer for detecting runaways.
TMPM330 (rev 0.4) 14-1
TMPM330
The watchdog timer (WDT) is for detecting malfunctions (runaways) of the CPU caused by noises or
other disturbances and remedying them to return the CPU to normal operation. If the timer detects a
runaway, it generates a non-maskable interrupt to notify the CPU and outputs “0” from the output pin
of the watchdog timer to notify peripherals.
By connecting the output of the watchdog timer to a reset pin (inside the chip), it is possible to force
the watchdog timer to reset itself.
14.1 Configuration
fSYS
Internal reset
Fig. 14-1 shows the block diagram of the watchdog timer
WDMOD
2 16 /fsys
Watchdog timer out
control
2 18 /fsys
2 20 /fsys
Selector
Write
4EH
2 22 /fsys
2 24 /fsys
2 26 /fsys
Binary counter (26 stages)
Reset
Write
B1H
Watch dog timer
Control Register WDCR
Internal data bus
WDMOD
Q
R S
WDMOD
Fig. 14-1 Block Diagram of the Watchdog Timer
RESET pin
Internal reset
WDTOUT
Interrupt
request
INTWDT
Watchdog Timer