UPD78F0838 Renesas Electronics Corporation., UPD78F0838 Datasheet - Page 340

• Manufacturer Part Number: UPD78F0838
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

9.3 Register Controlling Watchdog Timer
338
The watchdog timer is controlled by the watchdog timer enable register (WDTE).
(1) Watchdog timer enable register (WDTE)
Writing ACH to WDTE clears the watchdog timer counter and starts counting again.
This register can be set by an 8-bit memory manipulation instruction.
Reset signal generation sets this register to 9AH or 1AH
Note The WDTE reset value differs depending on the WDTON setting value of the option byte (0080H). To
Cautions 1. If a value other than ACH is written to WDTE, an internal reset signal is generated. If the
Address: FF9BH
Symbol
WDTE
operate watchdog timer, set WDTON to 1.
2. If a 1-bit memory manipulation instruction is executed for WDTE, an internal reset signal
3. The value read from WDTE is 9AH/1AH (this differs from the written value (ACH)).
0 (watchdog timer count operation disabled)
1 (watchdog timer count operation enabled)
source clock to the watchdog timer is stopped, however, an internal reset signal is
generated when the source clock to the watchdog timer resumes operation.
is generated. If the source clock to the watchdog timer is stopped, however, an internal
reset signal is generated when the source clock to the watchdog timer resumes operation.
7
Figure 9-2. Format of Watchdog Timer Enable Register (WDTE)
After reset: 9AH/1AH
WDTON Setting Value
6
Preliminary User’s Manual U19748EJ1V0UD
CHAPTER 9 WATCHDOG TIMER
Note
5
R/W
4
Note
.
1AH
9AH
3
WDTE Reset Value
2
1
0