Renesas RL78/G15 User Manual

RL78/G15 CHAPTER 5 CLOCK GENERATOR
R01UH0959EJ0110 Rev.1.10 Page 157 of 765
Mar 7, 2023
5.6.4 Condition before changing CPU clock and processing after changing CPU
clock
Condition before changing the CPU clock and processing after changing the CPU clock are shown below.
Table 5-4. Changing CPU Clock
CPU Clock Condition Before Change Processing After Change
Before Change After Change
High-speed on-chip
oscillator clock
X1 clock Stabilization of X1 oscillation
●
OSCSEL = 1, EXCLK = 0, MSTOP = 0
●
After elapse of oscillation stabilization
time
The operating current can be reduced by
stopping the high-speed on-chip oscillator
(HIOSTOP = 1) after checking that the
CPU clock is changed.
External main system
clock
An external clock input from the EXCLK
pin must be enabled.
●
OSCSEL = 1, EXCLK = 1, MSTOP = 0
X1 clock
High-speed on-chip
oscillator clock
Enabling oscillation of high-speed on-chip
oscillator
●
HIOSTOP = 0
●
After elapse of oscillation accuracy
stabilization time
X1 oscillation can be stopped (MSTOP =
1) after checking that the CPU clock is
changed.
External main system
clock
Change is not possible —
External main system
clock
High-speed on-chip
oscillator clock
Enabling oscillation of high-speed on-chip
oscillator
●
HIOSTOP = 0
●
After elapse of oscillation accuracy
stabilization time
External main system clock input can be
disabled (MSTOP = 1) after checking that
the CPU clock is changed.
X1 clock Change is not possible —

Renesas RL78/G15 Specifications

General

Brand	Renesas
Model	RL78/G15
Category	Microcontrollers
Language	English