Int 1AH [AT] [PS/2] Function 06H Set alarm

Sets an alarm in the CMOS date/time chip.

Call with:

AH = 06H

CH = hours in binary coded decimal (BCD)

CL = minutes in BCD

DH = seconds in BCD

Returns:

If function successful

Carry flag = clear

If function unsuccessful (alarm already set, or clock stopped)

Carry flag = set

Notes:

A side effect of this function is that the clock chip's interrupt level (IRQ8) is enabled.

Only one alarm may be active at any given time. The alarm occurs every 24 hours at the specified time until it is reset with Int 1AH Function 07H.

The program using this function must place the address of its interrupt handler for the alarm in the vector for Int 4AH.