Toshiba TMP91C815F Data Book page 200

3.13 Real time clock (RTC)
3.13.1 Function description for RTC
1) Clock function (hour , minute , second)
2) Calendar function (month and day , day of the week , and leap year)
3) 24 or 12-hour (AM/PM) clock function
4) ± 30 second adjustment function (by software)
5) Alarm function (Alarm output)
6) Alarm interrupt generate
3.13.2 Block diagram
32KHz
CLOCK: fs
1S CARRY
HOLD
ADJUST
CARRY
HOLD
ADJUST
RD
Figure 3.13(1) RTC block diagram
(note1) The Christian era year column:
This product has year column toward only lower two columns. Therefore the next
year in 99 works as 00 years. In system to use it, please manage upper two
columns with the system side when handle year column in the Christian era.
(note2) Leap year:
A leap year is the year which is divisible with 4, but the year which there is
exception, and is divisible with 100 is not a leap year. However, the year which is
divisible with 400 is a leap year. But there is not this product for the correspondence
to the above exception. Because there are only with the year which is divisible with
4 as a leap year, please cope with the system side if this function is problem.
Divider
ALARM REGISTER
COMPARATOR
TIMER
ADDRESS
BUS
READ/WRITE CONTROL
WR
D0〜D7
91C815-
16Hz Clock
1Hz Clock
/ALARM
DATA BUS
Address
197
TMP91C815
/ALARM
ALARM
SELECT INTRTC