HD6417705 Datasheet, PDF (411/739 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7700 Series

15.3.16 RTC Control Register 1 (RCR1)
The RTC control register 1 (RCR1) is an 8-bit readable/writable register that affects carry flags
and alarm flags. It also selects whether to generate interrupts for each flag. Because flags are
sometimes set after an operand read, do not use this register in read-modify-write processing.
RCR1 is initialized to H'00 by a power-on reset or a manual reset. In a reset, all bits are initialized
to 0 except for the CF flag, which is undefined. When using the CF flag, it must be initialized
beforehand. This register is not initialized in standby mode.
Bit
Bit Name Initial Value R/W Description
7
CF
Undefined R/W Carry Flag
Status flag that indicates that a carry has
occurred. CF is set to 1 when R64CNT or
RSECCNT is read during a carry occurrence by
R64CNT or RSECCNT. A count register value
read at this time cannot be guaranteed; another
read is required.
0: No carry by R64CNT or RSECCNT.
[Clearing condition] When 0 is written to CF
1: [Setting condition] When R64CNT or
RSECCNT is read during a carry occurrence by
R64CNT or RSECCNT, or 1 is written to CF
6, 5
—
0
R
Reserved
These bits are always read as 0. The write value
should always be 0.
4
CIE
0
R/W Carry Interrupt Enable Flag
When the carry flag (CF) is set to 1, the CIE bit
enables interrupts.
0: A carry interrupt is not generated when the CF
flag is set to 1
1: A carry interrupt is generated when the CF flag
is set to 1
3
AIE
0
R/W Alarm Interrupt Enable Flag
When the alarm flag (AF) is set to 1, the AIE bit
enables interrupts.
0: An alarm interrupt is not generated when the
AF flag is set to 1
1: An alarm interrupt is generated when the AF
flag is set to 1
Rev. 2.00, 09/03, page 365 of 690