tmp88cs38ng TOSHIBA Semiconductor CORPORATION, tmp88cs38ng Datasheet - Page 57

• Manufacturer Part Number: tmp88cs38ng
• Description: Cmos 8-bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

2.4.2
Watchdog Timer Control
watchdog timer is automatically enabled after reset.
(1) Malfunction detection methods using the watchdog timer
Figure 2.4.2 shows the watchdog timer control registers (WDTCR1, WDTCR2). The
watchdog timer output will become active at the rising of an overflow from the binary
counters unless the binary counters are cleared. At this time, when WDTOUT = 1 a
reset is generated, which drivers the
and the external circuit. When WDTOUT = 0, a watchdog timer interrupt (INTWDT) is
generated.
IDLE mode, and automatically restarts (Continues counting) when the STOP/IDLE
mode is released.
1.
2.
Note: The watchdog timer consists of an internal divider and two-stage binary counter.
The CPU malfunction is detected at follows.
If the CPU malfunctions such as endless looping or deadlock occur for any cause, the
The watchdog timer temporarily stops counting in STOP mode including warm-up or
Setting the detection time, selecting output, and clearing the binary counter.
Repeatedly clearing the binary counter within the setting detection time.
Writing the clear code (4E
The minimum overflow time for the binary counter might be three quarters of the
WDTCR1 (WDTT) time setting depending on when the clear code (4E
into the WDTCR2 register. So, write the clear code on a cycle which is shorter than
that minimum overflow time.
88CS38-57
H
) clears the binary counter, but not the internal divider.
RESET
pin low to reset the internal hardware
TMP88CS38/CM38A/CP38A
2007-09-12
H
) is written