HD6417320 RENESAS [Renesas Technology Corp], HD6417320 Datasheet - Page 645

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

17.5
17.5.1
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 stopped before writing to any of the above registers.
17.5.2
The method of using the periodic interrupt function is shown in figure 17.5.
A periodic interrupt can be generated periodically at the interval set by the flags 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 or when the flags PES0 to PES2 are set.
Periodic interrupt generation can be confirmed by reading this bit, but normally the interrupt
function is used.
17.5.3
When a transition to standby mode is made after registers in the RTC are set, sometimes counting
is not performed correctly. In case the registers are set, be sure to make a transition to standby
mode after waiting for two RTC clocks or more.
Usage Notes
Register Writing during RTC Count
Transition to Standby Mode after Setting Register
Use of Realtime Clock (RTC) Periodic Interrupts
Figure 17.5 Using Periodic Interrupt Function
Elapse of time set by PES
Set PES, clear PEF
Clear PEF
Set PES0 to PES2,
and clear PEF to 0,
in RCR2
Clear PEF to 0
Rev. 3.00 Jan. 18, 2008 Page 583 of 1458
Section 17 Realtime Clock (RTC)
REJ09B0033-0300