RL78/G13 CHAPTER 7 REAL-TIME CLOCK
R01UH0146EJ0100 Rev.1.00 439
Sep 22, 2011
(5) Second count register (SEC)
The SEC register is an 8-bit register that takes a value of 0 to 59 (decimal) and indicates the count value of
seconds.
It counts up when the sub-count register overflows.
When data is written to this register, it is written to a buffer and then to the counter up to 2 clocks (f
RTC) later. Set a
decimal value of 00 to 59 to this register in BCD code. If a value outside the range is set, the register value returns
to the normal value after 1 period.
The SEC register can be set by an 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 7-6. Format of Second Count Register (SEC)
Address: FFF92H After reset: 00H R/W
Symbol 7 6 5 4 3 2 1 0
SEC 0 SEC40 SEC20 SEC10 SEC8 SEC4 SEC2 SEC1
Caution When it reads or writes from/to the register while the counter is in operation (RTCE = 1), follow
the procedures described in the section 7.4.3 Reading/writing real-time clock.
(6) Minute count register (MIN)
The MIN register is an 8-bit register that takes a value of 0 to 59 (decimal) and indicates the count value of minutes.
It counts up when the second counter overflows.
When data is written to this register, it is written to a buffer and then to the counter up to 2 clocks (f
RTC) later. Even
if the second count register overflows while this register is being written, this register ignores the overflow and is set
to the value written. Set a decimal value of 00 to 59 to this register in BCD code. If a value outside the range is set,
the register value returns to the normal value after 1 period.
The MIN register can be set by an 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 7-7. Format of Minute Count Register (MIN)
Address: FFF93H After reset: 00H R/W
Symbol 7 6 5 4 3 2 1 0
MIN 0 MIN40 MIN20 MIN10 MIN8 MIN4 MIN2 MIN1
Caution When it reads or writes from/to the register while the counter is in operation (RTCE = 1), follow
the procedures described in the section 7.4.3 Reading/writing real-time clock.
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