TMPM330 - Keil

15.6 Alarm function
Under development
TMPM330 (rev0.4) 15-13
TMPM330
By writing “1” to PAGER, the alarm function of the PAGE1 registers is enabled. One of
the following three signals is output to the ALARM pin.
(1) “0” (when the alarm register corresponds with the clock)
(2) 1Hz clock
(3) 16Hz clock
The INTRTC outputs a 1-shot pulse by detecting the falling edge.
The RTC is not initialized by reset. Clear the interrupt request flag in the interrupt controller
when the clock or alarm function is used.
(1) “0” (when the alarm register corresponds with the clock)
Provided PAGER = “1”, “0” is output to the ALARM pin when the values of the
PAGE0 clock and the PAGE1 alarm register correspond. In combination with the setting and
PAGER=“1”, the INTRTC interrupt is generated and the alarm is triggered.
The alarm settings
To initialize the alarm, write “1” to RESTR. It makes all alarm settings “don’t
care”. In this case, the alarm always corresponds with the value of the clock. The INTRTC
interrupt request is generated if PAGER =”1”.
Setting alarm for min., hour, date and day is done by writing data to the relevant PAGE1
register. Each writing releases the “don’t care” state respectively.
When all setting contents correspond with the setting of PAGER
=1”, the RTC generates an INTRTC interrupt. However, contents which have not
been set up (“don't care” state) are always considered to be corresponding.
Contents which have already been set up cannot be returned independently but all
together to the “don’t care” state by initializing the alarm.
The following is an example program for outputting an alarm from the ALARM pin at noon
(PM12:00) every day.
7 6 5 4 3 2 1 0
PAGER ← 0 0 0 0 1 0 0 1 Disables alarm, sets PAGE1
RESTR ← 1 1 0 1 0 0 0 0 Initializes alarm
DAYR ← 0 0 0 0 0 0 0 1 W0
DATAR ← 0 0 0 0 0 0 0 1 1 day
HOURR ← 0 0 0 1 0 0 1 0 Sets 12 o’clock
MINR ← 0 0 0 0 0 0 0 0 Sets 00 min.
Set up time 31 μs (Note)
PAGER ← 0 0 0 0 1 1 0 0 Enables alarm
PAGER ← 1 0 0 0 1 1 0 0 Enables interrupt
When the CPU is operating at high frequency oscillation, it may take a maximum of one
clock at 32 kHz (about 30us) for the time register setting to become valid. In the above
example, it is necessary to set 31μs of set up time between setting the time register and
enabling the alarm register.
(Note) This set up time is unnecessary when you use only internal interruption.
Real Time Clock