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3.13.6
Explanation of the Alarm Function
Can use alarm function by setting of register of PAGE1 and output either of three
signals from
ALARM
1shot pulse when the falling edge is detected. RTC is not initializes by RESET. Therefore,
when clock or alarm function is used, clear interrupt request flag in INTC (interrupt
controller).
(1) In accordance of alarm register and the Clock, output 0
(2) Output clock of 1 Hz
(3) Output clock of 16 Hz
(1) In accordance with alarm register and a clock, output "0"
When value of a clock of PAGE0 accorded with alarm register of PAGE1 with a
state of PAGER<ENAALM>= "1", output "0" to
Follows are ways using alarm.
Initialization of alarm is done by writing in "1" at RESTR<RSTALM>, setting value
of all alarm becomes don't care. In this case, always accorded with value of a clock
and request INTRTC interrupt if PAGER<ENAALM> is "1".
Setting alarm min., alarm hour, alarm day and alarm the day week are done by
writing in data at each register of PAGE1.
When all setting contents accorded, RTC generates INTRTC interrupt, if
PAGER<INTENA><ENAALM> is "1". However, contents (don't care state) which does
not set it up is considered to always accord.
The contents, which set it up once, cannot be returned to don't care state in
independence. Initialization of alarm and resetting of alarm register set to "Don't
care".
The following is an example program for outputting alarm from
noon (PM12:00) every day.
LD
LD
LD
LD
LD
LD
LD
( LD
When CPU is operated by high frequency oscillation, it may take a maximum of one
clock at 32 kHz (about 30µs) 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.
pin as follows by write "1" to PAGER<PAGE>. INTRTC outputs
(PAGER), 09H
;
Alarm disable, setting PAGE1
(RESTR), D0H
;
Alarm initialize
(DAYR), 01H
;
W0
(DATAR),01H
1 day
(HOURR), 12H
;
Setting 12 o'clock
(MINR), 00H
;
Setting 00 min
Set up time 31 µs (Note)
;
(PAGER), 0CH
;
Alarm enable
(PAGER), 8CH
;
Interrupt enable )
91C824-211
TMP91C824
pin and occur INTRTC.
ALARM
ALARM
-pin at
2008-02-20
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