UPD78F1502AGK-GAK-AX Datasheet, PDF (364/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 7 REAL-TIME COUNTER
(1) Peripheral enable register 0 (PER0)
PER0 is used to enable or disable use of each peripheral hardware macro. 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 counter is used, be sure to set bit 7 (RTCEN) of this register to 1.
PER0 can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 7-2. Format of Peripheral Enable Register 0 (PER0)
Address: F00F0H After reset: 00H R/W
Symbol
<7>
<6>
<5>
PER0
RTCEN
DACEN
ADCEN
<4>
IICAEN^Note1
<3>
SAU1EN
<2>
SAU0EN
<1>
TAU1EN
<0>
TAU0EN
RTCEN
0
1
Control of real-time counter (RTC) input clock^Note2
Stops supply of input clock.
• SFR used by the real-time counter (RTC) cannot be written.
• The real-time counter (RTC) is in the reset status.
Supplies input clock.
• SFR used by the real-time counter (RTC) can be read/written.
Notes 1.
2.
78K0R/LG3, 78K0R/LH3 only
By using RTCEN, can supply and stop the clock that is used when accessing the real-time
counter (RTC) from the CPU. RTCEN cannot control supply of the operating clock (fSUB) to
RTC.
Cautions 1. When using the real-time counter, first set RTCEN to 1, while oscillation of the
subsystem clock (fSUB) is stable. If RTCEN = 0, writing to a control register of the
real-time counter is ignored, and, even if the register is read, only the default value is
read.
2. Clock supply to peripheral functions except the real-time counter can be stopped in
the HALT mode when operating on the subsystem clock by setting RTCLPC of the
operation speed mode control register (OSMC) to 1. In this case, set RTCEN to 1 and
bits 0 to 6 of PER0 to 0.
(2) Real-time counter control register 0 (RTCC0)
The RTCC0 register is an 8-bit register that is used to start or stop the real-time counter operation, control the
RTCCL and RTC1HZ pins, and set a 12- or 24-hour system and the constant-period interrupt function.
RTCC0 can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
R01UH0004EJ0501 Rev.5.01
348
Jun 20, 2011