Casio IT-2000W - Manual (Page 190)

190
Setting Status of Alarm
This function is used to set the alarm so that Int4Ah will be executed at the specified time. If the set
time precedes the currently set RTC (Real Time Clock) time, the alarm will be valid on and after the
following day. If the setup time is later than the currently set RTC time, the alarm will be valid from
the specified day. To make this possible the user has to set the specified interrupt handling routine to
Int4Ah. If this function is not reset using the SYS_ResetAlarm() function, the alarm will activate
(repeatedly set) for each 24-hour period. Call the SYS_SetPowerOnAlarm() function to turn on the
system at the alarm time specified by this function.
SYNTAX
int SYS_SetAlarm(int hour, int min, int sec);
INPUT
hour = hours (in decimal number)
min = minutes (in decimal number)
sec = seconds (in decimal number)
OUTPUT
0 Normal
< 0 Error (error within INT1Ah)
Note:

This function simply calls INT1AH (AH = 6) internally. Therefore, if this function or INT1Ah
(AH=6) is called and if the alarm has already been set, an error results.

Note that the validity of parameters as time is not checked.