Specifications

PC/II+p Board Technical Reference Manual 77

7.29.3 WatchdogEnable() Function

This function causes the Watchdog timer to enter the Watchdog Enabled mode – the application must issue

periodic strobes at a frequency of 1 Hz or better, using the function WatchdogStrobe(), to prevent a

Watchdog timer expiry and subsequent system Reset.

A MASM example follows:

MOV AH,0FEh

MOV AL,<01h>

INT 15h

-- returns here after the Enabled Watchdog MODE has been entered

/ ALL Registers are preserved

7.29.4 WatchdogDisable() Function

This function causes the Watchdog timer to enter the Watchdog Disabled mode (the default mode set by the

BIOS at boot time) – the Watchdog timer is automatically strobed by the PC/II+p hardware and the

application does not need to issue strobes. This mode is supported entirely by the PC/II+p hardware

independent of the CPU.

A MASM example follows:

MOV AH,0FEh

MOV AL,<00h>

INT 15h

-- returns here after the specified watchdog MODE has been entered

/ ALL Registers are preserved

7.29.5 WatchdogStrobe() Function

This function causes one strobe to be issued to the Watchdog timer – the Watchdog timer is restarted. In

Watchdog Enabled mode, the application must call this function at a frequency of 1 Hz or better to prevent

expiry of the Watchdog timer and subsequent system Reset. If the Watchdog timer is in Watchdog Disabled

mode, the application need not call this function (calling it in this mode is treated as a No Operation).

A MASM example follows:

MOV AH,0FDh

INT 15h

-- returns here after one strobe has been issued to the watchdog

/ ALL Registers are preserved