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RL78/G1A CHAPTER 5 CLOCK GENERATOR
R01UH0305EJ0200 Rev.2.00 165
Jul 04, 2013
5.6 Controlling Clock
5.6.1 Example of setting high-speed on-chip oscillator
After a reset release, the CPU/peripheral hardware clock (f
CLK) always starts operating with the high-speed on-chip
oscillator clock. The frequency of the high-speed on-chip oscillator can be selected from 32, 24, 16, 12, 8, 6, 4, 3, 2, and 1
MHz by using FRQSEL0 to FRQSEL3 of the option byte (000C2H).
[Option byte setting]
Address: 000C2H
7 6 5 4 3 2 1 0
Option
byte
(000C2H)
CMODE1
0/1
CMODE0
0/1
1
0
FRQSEL3
0/1
FRQSEL2
0/1
FRQSEL1
0/1
FRQSEL0
0/1
CMODE1 CMODE0 Setting of flash operation mode
0 0
LV (low voltage main) mode V
DD = 1.6 V to 3.6 V @ 1 MHz to 4 MHz
1 0
LS (low speed main) mode V
DD = 1.8 V to 3.6 V @ 1 MHz to 8 MHz
1 1
HS (high speed main) mode V
DD = 2.4 V to 3.6 V @ 1 MHz to 16 MHz
V
DD = 2.7 V to 3.6 V @ 1 MHz to 32 MHz
Other than above Setting prohibited
FRQSEL3 FRQSEL2 FRQSEL1 FRQSEL0 Frequency of the high-speed on-chip oscillator
1 0 0 0
32 MHz
0 0 0 0
24 MHz
1 0 0 1
16 MHz
0 0 0 1
12 MHz
1 0 1 0
8 MHz
0 0 1 0
6 MHz
1 0 1 1
4 MHz
0 0 1 1
3 MHz
1 1 0 0
2 MHz
1 1 0 1
1 MHz
Other than above Setting prohibited
[High-speed on-chip oscillator frequency select register (HOCODIV) setting]
Address: F00A8H
7 6 5 4 3 2 1 0
HOCODIV
0 0 0 0 0 HOCODIV2 HOCODIV1 HOCODIV0
Selection of high-speed on-chip oscillator clock frequency
HOCODIV2 HOCODIV1 HOCODIV0
FRQSEL3 Bit is 0 FRQSEL3 Bit of is 1
0 0 0 24 MHz 32 MHz
0 0 1 12 MHz 16 MHz
0 1 0 6 MHz 8 MHz
0 1 1 3 MHz 4 MHz
1 0 0 Setting prohibited 2 MHz
1 0 1 Setting prohibited 1 MHz
Other than above Setting prohibited