SH7706 Datasheet, PDF (409/749 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH™ RISC engine Family/SH7700 Series

13.5 Usage Note
Section 13 Realtime Clock (RTC)
13.5.1 Register Writing during RTC Count
The following RTC registers cannot be written to during an RTC count (while bit 0 = 1 in RCR2).
RSECCNT, RMINCNT, RHRCNT, RDAYCNT, RWKCNT, RMONCNT, RYRCNT
The RTC count must be halted before writing to any of the above registers.
13.5.2 Use of Realtime Clock (RTC) Periodic Interrupts
The method of using the periodic interrupt function is shown in figure 13.6.
A periodic interrupt can be generated periodically at the interval set by the periodic interrupt
enable flag (PES0 to PES2) in RCR2. When the time set by the PES0 to PES2 has elapsed, the
PEF is set to 1.
The PEF is cleared to 0 upon periodic interrupt generation when the periodic interrupt enable flag
(PES0 to PES2) is set. Periodic interrupt generation can be confirmed by reading this bit, but
normally the interrupt function is used.
Set PES, clear PEF
Set PES0 to PES2,
and clear PEF to 0,
in RCR2
Elapse of time set by PES
Clear PEF
Clear PEF to 0
Figure 13.6 Using Periodic Interrupt Function
Rev. 5.00 May 29, 2006 page 361 of 698
REJ09B0146-0500