SH7708 Datasheet, PDF (348/625 Pages) Renesas Technology Corp – SuperH™ RISC engine

12.4 Usage Notes
12.4.1 Flag Clearing
With the SH7708, the procedure shown in the flowchart below should be used to clear the carry
flag (CF) and alarm flag (AF) in realtime clock (RTC) register RCR1 (RTC control register 1) and
the peripheral interrupt flag (PEF) in register RCR2 (RTC control register 2).
Entire lot
Clear AF flag
Wait for 63 µs or more
1. Transition to standby mode
2. Change STC0, STC1 in FEQCR (frequency control register)
3. Change MSTP1 in STBCR (standby control register)
Figure 12.6 AF Flag Clearing
If an interval of at least 63 µs is not allowed, the AF flag may not be set even if the setting
conditions are satisfied. Use the same procedure for clearing the CF and PEF flags.
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