SH7709S Datasheet, PDF (463/807 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer Super RISC engine Family/SH7700 Series

13.2.15 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 manual reset, all bits are
initialized to H'00 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: 7
6
CF
—
Initial value: 0
0
R/W: R/W
R
5
4
3
2
—
CIE
AIE
—
0
0
0
0
R
R/W R/W
R
1
0
—
AF
0
0
R
R/W
Bit 7—Carry Flag (CF): Status flag that indicates that a carry has occurred. Setting CF to 1
indicates reading of a counter register value has occurred when (1) the second counter is carried or
(2) the 64-Hz counter is carried. A count register value read at this time cannot be guaranteed;
another read is required.
Bit 7: CF
0
1
Description
No count up of R64CNT or RSECCNT
Clearing condition: When 0 is written to CF
Count up of R64CNT or RSECCNT
Setting condition: When 1 is written to CF
(Initial value)
Bits 6, 5, 2, and 1—Reserved: These bits are always read as 0. The write value should always be
0.
Bit 4—Carry Interrupt Enable Flag (CIE): When the carry flag (CF) is set to 1, the CIE bit
enables interrupts.
Bit 4: CIE
0
1
Description
A carry interrupt is not generated when the CF flag is set to 1 (Initial value)
A carry interrupt is generated when the CF flag is set to 1
Rev. 5.00, 09/03, page 419 of 760