RL78/F13, F14 CHAPTER 5 CLOCK GENERATOR
R01UH0368EJ0210 Rev.2.10 386
Dec 10, 2015
5.3.8 High-Speed On-Chip Oscillator Frequency Select Register (HOCODIV)
The frequency of the high-speed on-chip oscillator which is set by a user option byte (000C2H/020C2H) can be changed
by using high-speed on-chip oscillator frequency select register (HOCODIV). However, the selectable frequency
depends on the FRQSEL4 and FRQSEL3 bits of the user option byte (000C2H/020C2H).
Set the HOCODIV register by an 8-bit memory manipulation instruction.
Reset signal generation clears this register to default value (the value set with the FRQSEL2 to FRQSEL0 bits of the
user option byte (000C2H/020C2H)).
Figure 5-15. Format of High-speed on-chip oscillator frequency select register (HOCODIV)
Address: F00A8H After reset: value set with the FRQSEL2 to FRQSEL0 bits of the user option byte (000C2H/020C2H) R/W
Symbol 7 6 5 4 3 2 1 0
HOCODIV
0 0 0 0 0 HOCODIV2 HOCODIV1 HOCODIV0
HOCODIV2 HOCODIV1 HOCODIV0
Selection of high-speed on-chip oscillator clock frequency
24-MHz base 32-MHz base 48-MHz base 64-MHz base
FRQSEL4 = 0 FRQSEL4 = 1
FRQSEL3 = 0 FRQSEL3 = 1 FRQSEL3 = 0 FRQSEL3 = 1
0 0 0 fIH = 24 MHz fIH = 32 MHz
f
IH = 48 MHz fIH = 64 MHz
0 0 1 fIH = 12 MHz fIH = 16 MHz
f
IH = 24 MHz fIH = 32 MHz
0 1 0 fIH = 6 MHz fIH = 8 MHz
f
IH = 12 MHz fIH = 16 MHz
0 1 1 fIH = 3 MHz fIH = 4 MHz
f
IH = 6 MHz fIH = 8 MHz
1 0 0
Setting
prohibited
f
IH = 2 MHz
Setting
prohibited
f
IH = 4 MHz
1 0 1
Setting
prohibited
fIH = 1 MHz
Setting
prohibited
f
IH = 2 MHz
Other than above Setting prohibited
Cautions 1. When setting of high-speed on-chip oscillator clock as system clock, the device
operates at the old frequency for the duration of 3 clocks after the frequency value
has been changed by using the HOCODIV register.
2. To change the frequency of the high-speed on-chip oscillator when X1 oscillation,
external oscillation input, subsystem clock, or low-speed on-chip oscillator clock
is set for the system clock, stop the high-speed on-chip oscillator by setting bit 0
(HIOSTOP) of the CSC register to 1 and then change the frequency.
3. To change the frequency of the high-speed on-chip oscillator when X1 oscillation
or external oscillation input is set for the clock source of the PLL clock, and PLL
clock is set for the system clock, stop the high-speed on-chip oscillator by setting
bit 0 (HIOSTOP) of the CSC register to 1 and then change the frequency.
4. Do not change the setting of the HOCODIV register when the high-speed on-chip
oscillator clock is used as the clock source of the PLL clock and the PLL clock is
used as the system clock.
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