Datasheet

CHAPTER 9 REAL-TIME COUNTER
User’s Manual U18698EJ1V0UD
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(7) 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 (32.768 kHz)
later. Set a decimal value of 00 to 59 to this register in BCD code. If a value outside this range is set, the
register value returns to the normal value after 1 period.
MIN can be set by an 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 9-8. Format of Minute Count Register (MIN)
Address: FF63H After reset: 00H R/W
Symbol 7 6 5 4 3 2 1 0
MIN 0 MIN40 MIN20 MIN10 MIN8 MIN4 MIN2 MIN1
(8) Hour count register (HOUR)
The HOUR register is an 8-bit register that takes a value of 0 to 23 or 1 to 12 (decimal) and indicates the count
value of hours.
It counts up when the minute counter overflows.
When data is written to this register, it is written to a buffer and then to the counter up to 2 clocks (32.768 kHz)
later. Set a decimal value of 00 to 23, 01 to 12, or 21 to 32 to this register in BCD code. If a value outside this
range is set, the register value returns to the normal value after 1 period.
HOUR can be set by an 8-bit memory manipulation instruction.
Reset signal generation clears this register to 12H.
However, the value of this register is 00H if the AMPM bit is set to 1 after reset.
Figure 9-9. Format of Hour Count Register (HOUR)
Address: FF64H After reset: 12H R/W
Symbol 7 6 5 4 3 2 1 0
HOUR 0 0 HOUR20 HOUR10 HOUR8 HOUR4 HOUR2 HOUR1
Caution Bit 5 (HOUR20) of HOUR indicates AM(0)/PM(1) if AMPM = 0 (if the 12-hour system is
selected).