Example Of Setting X1 Oscillation Clock - Renesas RL78/G1H User Manual

16-bit single-chip microcontrollers
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RL78/G1H
6.6.2

Example of setting X1 oscillation clock

After a reset release, the CPU/peripheral hardware clock (f
chip oscillator clock. To subsequently change the clock to the X1 oscillation clock, set the oscillator and start
oscillation by using the oscillation stabilization time select register (OSTS), clock operation mode control register
(CMC), and clock operation status control register (CSC) and wait for oscillation to stabilize by using the
oscillation stabilization time counter status register (OSTC). After the oscillation stabilizes, set the X1 oscillation
clock to f
by using the system clock control register (CKC).
CLK
[Register settings] Set the register in the order of <1> to <5> below.
<1>
Set (1) the OSCSEL bit of the CMC register, except for the cases where the fx is equal to or more than 10 MHz, in
such cases set (1) the AMPH bit, to operate the X1 oscillator.
7
EXCLK
CMC
0
<2>
Using the OSTS register, select the oscillation stabilization time of the X1 oscillator at releasing of the STOP
mode.
Example: Setting values when a wait of at least 102 μs is set based on a 10 MHz resonator.
7
OSTS
0
<3>
Clear (0) the MSTOP bit of the CSC register to start oscillating the X1 oscillator.
7
MSTOP
CSC
0
<4>
Use the OSTC register to wait for oscillation of the X1 oscillator to stabilize.
Example: Wait until the bits reach the following values when a wait of at least 102 μs is set based on a 10 MHz
resonator.
7
MOST8
OSTC
1
<5>
Use the MCM0 bit of the CKC register to specify the X1 oscillation clock as the CPU/peripheral hardware clock.
7
CLS
CKC
0
R01UH0575EJ0120 Rev. 1.20
Dec 22, 2016
6
5
OSCSEL
EXCLKS
1
0
6
5
0
0
6
5
XTSTOP
1
0
6
5
MOST9
MOST10
1
1
6
5
CSS
MCS
0
0
) always starts operating with the high-speed on-
CLK
4
3
OSCSELS
0
0
4
3
0
0
4
3
0
0
4
3
MOST11
MOST13
0
0
4
3
MCM0
1
0
CHAPTER 6 CLOCK GENERATOR
2
1
AMPHS1
AMPHS0
0
0
2
1
OSTS2
OSTS1
0
1
2
1
0
0
2
1
MOST15
MOST17
0
0
2
1
0
0
Page 126 of 920
0
AMPH
0/1
0
OSTS0
0
0
HIOSTOP
0
0
MOST18
0
0
0

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