Datasheet

Real Time Clock (RTC)
Technical Data MC68HC908LJ12 — Rev. 2.1
222 Real Time Clock (RTC) Freescale Semiconductor
12.6.4 Alarm Minute and Hour Registers (ALMR and ALHR)
These read/write registers contain the alarm minute and hour values for
the hour and minute alarm function. When the hour counter matches the
value in the alarm hour register (ALHR) and the minute counter matches
the value in the alarm minute register (ALMR), the alarm flag, ALMF, is
set. When ALMF is set and the alarm interrupt enable bit, ALMIE, is also
set, a CPU interrupt request is generated.
NOTE: Writing values other than 0 to 59, to ALMR is possible, but the alarm flag
will never be set.
NOTE: Writing values other than 0 to 23, to ALHR is possible, but the alarm flag
will never be set.
Address: $0045
Read:
00
AM5 AM4 AM3 AM2 AM1 AM0
Write:
Reset:00000000
= Unimplemented
Figure 12-6. Alarm Minute Register (ALMR)
Address: $0046
Read:
000
AH4 AH3 AH2 AH1 AH0
Write:
Reset:00000000
= Unimplemented
Figure 12-7. Alarm Hour Register (ALHR)