user manual

Rev. 5.00, 09/03, page 411 of 760
13.2 RTC Registers
13.2.1 64-Hz Counter (R64CNT)
The 64-Hz counter (R64CNT) is an 8-bit read-only register that indicates the states of the RTC
divider circuit, RTC prescaler, and R64CNT between 64 Hz and 1 Hz.
R64CNT is initialized to H'00 by setting the RESET bit in RTC control register 2 (RCR2) or the
ADJ bit in RCR2 to 1.
R64CNT is not initialized by a power-on reset or manual reset, or in standby mode.
Bit 7 is always read as 0.
Bit:76543210
— 1Hz 2Hz 4Hz 8Hz 16Hz 32Hz 64Hz
Initial value:0 ———————
R/W:RRRRRRRR
13.2.2 Second Counter (RSECCNT)
The second counter (RSECCNT) is an 8-bit readable/writable register used for setting/counting in
the BCD-coded second section of the RTC. The count operation is performed by a carry for each
second of the 64-Hz counter.
The range that can be set is 00–59 (decimal). Errant operation will result if any other value is set.
Carry out write processing after halting the count operation with the START bit in RCR2.
RSECCNT is not initialized by a power-on reset or manual reset, or in standby mode.
Bit:76543210
— 10 seconds 1 second
Initial value:0 ———————
R/W: R R/W R/W R/W R/W R/W R/W R/W