Datasheet
78K0/Kx2-L CHAPTER 10 REAL-TIME COUNTER
R01UH0028EJ0400 Rev.4.00 378
Sep 27, 2010
(5) Sub-count register (RSUBC)
The RSUBC register is a 16-bit register that counts the reference time of 1 second of the real-time counter. It takes
a value of 0000H to 7FFFH and counts 1 second with a clock of 32.768 kHz.
RSUBC can be set by a 16-bit memory manipulation instruction.
Reset signal generation clears this register to 0000H.
Cautions 1. When a correction is made by using the SUBCUD register, the value may become 8000H or
more.
2. This register is also cleared by reset effected by writing the second count register.
3. The value read from this register is not guaranteed if it is read during operation, because a
value that is changing is read.
Figure 10-6. Format of Sub-Count Register (RSUBC)
Address: FFB0H, FFB1H After reset: 0000H R
Symbol 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RSUBC
(6) 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-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.
SEC can be set by an 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 10-7. Format of Second Count Register (SEC)
Address: FFB2H After reset: 00H R/W
Symbol 7 6 5 4 3 2 1 0
SEC 0 SEC40 SEC20 SEC10 SEC8 SEC4 SEC2 SEC1
FFB1H
FFB0H