HD6417320 RENESAS [Renesas Technology Corp], HD6417320 Datasheet - Page 625

• Manufacturer Part Number: HD6417320
• Description: Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

17.3.1
R64CNT indicates the state of the divider circuit between 64 Hz and 1 Hz.
Reading this register, when carry from 128-Hz divider stage is generated, sets the CF bit in the
RTC control register 1 (RCR1) to 1 so that the carrying and reading 64 Hz counter are performed
at the same time is indicated. In this case, the R64CNT should be read again after writing 0 to the
CF bit in RCR1 since the read value is not valid.
After the RESET bit or ADJ bit in the RTC control register 2 (RCR2) is set to 1, the RTC divider
circuit is initialized and R64CNT is initialized to H'00.
R64CNT is not initialized by a power-on reset or manual reset, or in standby mode.
Bit
7
6
5
4
3
2
1
0
64-Hz Counter (R64CNT)
Bit Name

1 Hz
2 Hz
4 Hz
8 Hz
16 Hz
32 Hz
64 Hz
Initial Value
0
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
R/W
R
R
R
R
R
R
R
R
Description
Reserved
This bit is always read as 0. Writing has no effect.
Indicate the state of the divider circuit between
64 Hz and 1 Hz.
Rev. 3.00 Jan. 18, 2008 Page 563 of 1458
Section 17 Realtime Clock (RTC)
REJ09B0033-0300