Renesas RL78/F14 User Manual

RL78/F13, F14 CHAPTER 9 REAL-TIME CLOCK
R01UH0368EJ0210 Rev.2.10 659
Dec 10, 2015
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 the operation clock of the real-time clock by the RTCCL register before
setting bit 7 (RTCEN) of this register to 1.
Set the PER0 register by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Writing to the PER0 register is disabled when the GCSC bit of the IAWCTL register is set to 1.
Figure 9-2. Format of Peripheral Enable Register 0 (PER0)
Address: F00F0H After reset: 00H R/W
Symbol <7> 6 <5> <4> <3> <2> <1> <0>
PER0 RTCEN 0 ADCEN
IICA0EN
Notes 1, 2
SAU1EN
Note 1
SAU0EN
TAU1EN
Note 1
TAU0EN
RTCEN Control of input clock supply to real-time clock (RTC)
0
Stops input clock supply.
 SFR used by the real-time clock (RTC) cannot be written.
 The real-time clock (RTC) is in the reset status.
1
Enables input clock supply.
 SFR used by the real-time clock (RTC) can be read/written.
Notes 1. Not provided in the RL78/F13 (LIN incorporated) products with 20, 30, 32, 48, or 64 pins and 16
Kbytes to 64 Kbytes of code flash memory.
2. Not provided in 30-pin products of the RL78/F13 (CAN and LIN incorporated) and 30-pin products
of the RL78/F14.
Cautions 1. When using the real-time clock, first set the RTCEN bit to 1, while oscillation of the
input clock (f
RTC) is stable. If RTCEN = 0, writing to a control register of the real-time
clock is ignored, and, even if the register is read, only the default value is read (except
for the operation speed mode control register (OSMC), timer input select registers 1
and 2 (TIS1 and TIS2), and RTC clock select register (RTCCL).
2. Clock supply to peripheral functions other than the real-time clock can be stopped in
HALT mode when the subsystem/low-speed on-chip oscillator select clock is used, by
setting the RTCLPC bit of the operation speed mode control register (OSMC) to 1. In
this case, set the RTCEN bit of the PER0 register to 1 and the other bits (bits 0 to 6) to
0.
3. Be sure to set the operating clock of the real-time clock by RTCCL register before
setting bit 7 (RTCEN) of this register to 1.
4. Be sure to clear the following bits to 0.
 Bits 1, 3, 4, and 6 in the RL78/F13 (LIN incorporated) products with 20, 30, 32, 48, or
64 pins and 16 Kbytes to 64 Kbytes of code flash memory
 Bits 4 and 6 in 30-pin products of the RL78/F13 (CAN and LIN incorporated) and in
30-pin products of the RL78/F14
 Bit 6 in the products other than above

Renesas RL78/F14 Specifications

General

Brand	Renesas
Model	RL78/F14
Category	Computer Hardware
Language	English