C541U_99 Datasheet, PDF (158/192 Pages) Siemens Semiconductor Group – 8-BIT CMOS MICROCONTROLLER

Fail Safe Mechanisms
C541U
8.1.2 Watchdog Timer Control / Status Flags
The watchdog timer is controlled by control and status flags which are located in SFR WDCON.
Special Function Register WDCON (Address C0H)
Reset Value : XXXX 0000B
Bit No. MSB
LSB
7
6
5
4
3
2
1
0
C0H
–
–
–
– OWDS WDTS WDT SWDT WDCON
Bit
–
OWDS
WDTS
WDT
SWDT
Function
Reserved bits for future use.
Oscillator watchdog timer status flag.
Set by hardware when an oscillator watchdog reset occured. Can be
set and cleared by software.
Watchdog timer status flag.
Set by hardware when a watchdog timer reset occured. Can be
cleared and set by software.
Watchdog timer refresh flag.
Set to initiate a refresh of the watchdog timer. Must be set directly
before SWDT is set to prevent an unintentional refresh of the
watchdog timer.
Watchdog timer start flag.
Set to activate the watchdog timer. When directly set after setting
WDT, a watchdog timer refresh is performed.
Semiconductor Group
8-3
1997-10-01