CHAPTER 9 REAL-TIME CLOCK
Page 239 of 920
9.3.1
Peripheral enable register 0 (PER0)
This register is used to enable or disable supplying the clock to the peripheral hardware. Clock supply to a
hardware macro that is not used is stopped in order to reduce the power consumption and noise.
When the real-time clock is used, be sure to set bit 7 (RTCEN) of this register to 1.
The PER0 register can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 9 - 2 Format of Peripheral enable register 0 (PER0)
Caution 1. When using the real-time clock, first set the RTCEN bit to 1 and then set the following registers, while
oscillation of the count clock (f
RTC
) is stable. If RTCEN = 0, writing to the control registers of the real-
time clock is ignored, and, even if the registers are read, only the default values are read (except for
the subsystem clock supply mode control register (OSMC), port mode register 3 (PM3), port register
3 (P3)).
• Real-time clock control register 0 (RTCC0)
• Real-time clock control register 1 (RTCC1)
• Second count register (SEC)
• Minute count register (MIN)
• Hour count register (HOUR)
• Day count register (DAY)
• Week count register (WEEK)
• Month count register (MONTH)
• Year count register (YEAR)
• Watch error correction register (SUBCUD)
• Alarm minute register (ALARMWM)
• Alarm hour register (ALARMWH)
• Alarm week register (ALARMWW)
Caution 2. Subsystem clock supply to peripheral functions other than the real-time clock and 12-bit interval
timer can be stopped in STOP mode or HALT mode when the subsystem clock is used, by setting the
RTCLPC bit of the subsystem clock supply mode control register (OSMC) to 1.
Address: F00F0H
After reset: 00H
Symbol
<7>
<6>
<5>
<4>
<3>
<2>
<1>
<0>
RTCEN
IICA1EN
ADCEN
IICA0EN
SAU1EN
SAU0EN
TAU1EN
TAU0EN
Control of real-time clock (RTC) and 12-bit interval timer input clock supply
0
Stops input clock supply.
• SFR used by the real-time clock (RTC) and 12-bit interval timer cannot be written.
• The real-time clock (RTC) and 12-bit interval timer are in the reset status.
1
Input clock supply.
• SFR used by the real-time clock (RTC) and 12-bit interval timer can be read/written.
Summary of Contents for RL78/G1H
Page 941: ...R01UH0575EJ0120 RL78 G1H...
