RL78/F13, F14 CHAPTER 9 REAL-TIME CLOCK
R01UH0368EJ0210 Rev.2.10 672
Dec 10, 2015
9.3.13 Month count register (MONTH)
The MONTH register is an 8-bit register that takes a value of 1 to 12 (decimal) and indicates the count value of months.
It counts up when the day counter overflows.
When data is written to this register, it is written to a buffer and then to the counter up to 2 operating clocks (f
RTC) later.
Even if the day 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 01 to 12 to this register in BCD code.
Set the MONTH register by an 8-bit memory manipulation instruction.
Reset signal generation clears this register to 01H.
Figure 9-14. Format of Month Count Register (MONTH)
Address: FFF97H After reset: 01H R/W
Symbol 7 6 5 4 3 2 1 0
MONTH 0 0 0 MONTH10 MONTH8 MONTH4 MONTH2 MONTH1
Caution When it reads or writes from/to the register while the counter is in operation (RTCE = 1), see
9.4.3 Reading/writing real-time clock and follow the described procedures.
9.3.14 Year count register (YEAR)
The YEAR register is an 8-bit register that takes a value of 0 to 99 (decimal) and indicates the count value of years.
It counts up when the month count register (MONTH) overflows.
Values 00, 04, 08, …, 92, and 96 indicate a leap year.
When data is written to this register, it is written to a buffer and then to the counter up to 2 operating clocks (f
RTC) later.
Even if the MONTH 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 99 to this register in BCD code.
Set the YEAR register by an 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 9-15. Format of Year Count Register (YEAR)
Address: FFF98H After reset: 00H R/W
Symbol 7 6 5 4 3 2 1 0
YEAR YEAR80 YEAR40 YEAR20 YEAR10 YEAR8 YEAR4 YEAR2 YEAR1
Caution When it reads or writes from/to the register while the counter is in operation (RTCE = 1), see
9.4.3 Reading/writing real-time clock and follow the described procedures.
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