INT 15,C3 - Enable/Disable Watchdog Timer (PS/2)

AH = C3

AL = 0 disable watchdog time-out

= 1 enable watchdog time-out

BX = watchdog timer count (1-255)

on return:

CF = 0 if successful

= 1 if error

AH = when CF set, 80h for PC & PCjr, 86h for XT, AT & Model 30

- the watchdog timer is available only on PS/2 with 80286 and

80386 processors.

- the ~timer~ uses channel timer channel 3 and IRQ0. Activated

when IRQ0 is active for more than one channel 0 timer cycle,

which causes the timer to be decremented. When the watch-

dog timer reaches 0, and NMI is generated.