RL78/G13 CHAPTER 7 REAL-TIME CLOCK
R01UH0146EJ0100 Rev.1.00 435
Sep 22, 2011
(2) Operation speed mode control register (OSMC)
The WUTMMCK0 bit can be used to select the real-time clock operation clock (fRTC).
In addition, by stopping clock functions that are unnecessary, the RTCLPC bit can be used to reduce power
consumption. For details about setting the RTCLPC bit, see CHAPTER 5 CLOCK GENERATOR.
The OSMC register can be set by an 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 7-3. Format of Operation Speed Mode Control Register (OSMC)
Address: F00F3H After reset: 00H R/W
Symbol 7 6 5 4 3 2 1 0
OSMC RTCLPC 0 0
WUTMMCK0
0 0 0 0
WUTMMCK0
Selection of operation clock (fRTC) for real-time clock and interval timer.
0 Subsystem clock (fSUB)
1 Low-speed on-chip oscillator clock (fIL)
Caution The count of year, month, week, day, hour, minutes and second can only be performed when a
subsystem clock (f
SUB = 32.768 kHz) is selected as the operation clock of the real-time clock.
When the low-speed oscillation clock (f
IL) is selected, only the constant-period interrupt
function is available. The 20- to 36-pin products have the constant-period interrupt function
only, because these products have no subsystem clock.
However, the constant-period interrupt interval when f
IL is selected will be calculated with the
constant-period (the value selected with RTCC0 register) × fSUB/fIL.
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