Renesas RL78/G1H User Manual

RL78/G1H CHAPTER 6 CLOCK GENERATOR
R01UH0575EJ0120 Rev. 1.20 Page 135 of 920
Dec 22, 2016
6.6.5 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 6 - 8 Changing CPU Clock (1/2)
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
After checking that the CPU clock is
switched to the clock after change,
operating current can be reduced
by stopping high-speed on-chip
oscillator (HIOSTOP = 1).
External main system
clock
Enabling input of external clock from the
EXCLK pin
• OSCSEL = 1, EXCLK = 1, MSTOP = 0
XT1 clock Stabilization of XT1 oscillation
• OSCSELS = 1, EXCLKS = 0, XTSTOP = 0
• After elapse of oscillation stabilization time
External subsystem
clock
Enabling input of external clock from the
EXCLKS pin
• OSCSELS = 1, EXCLKS = 1, XTSTOP = 0
X1 clock High-speed on-chip
oscillator clock
Enabling oscillation of high-speed on-chip
oscillator
• HIOSTOP = 0
• After elapse of oscillation stabilization time
After checking that the CPU clock is
switched to the clock after change,
X1 oscillation can be stopped
(MSTOP = 1).
External main system
clock
Transition not possible —
XT1 clock Stabilization of XT1 oscillation
• OSCSELS = 1, EXCLKS = 0, XTSTOP = 0
• After elapse of oscillation stabilization time
After checking that the CPU clock is
switched to the clock after change,
X1 oscillation can be stopped
(MSTOP = 1).
External subsystem
clock
Enabling input of external clock from the
EXCLKS pin
• OSCSELS = 1, EXCLKS = 1, XTSTOP = 0
External main
system clock
High-speed on-chip
oscillator clock
Enabling oscillation of high-speed on-chip
oscillator
• HIOSTOP = 0
• After elapse of oscillation stabilization time
After checking that the CPU clock is
switched to the clock after change,
external main system clock input
can be disabled (MSTOP = 1).
X1 clock Transition not possible —
XT1 clock Stabilization of XT1 oscillation
• OSCSELS = 1, EXCLKS = 0, XTSTOP = 0
• After elapse of oscillation stabilization time
After checking that the CPU clock is
switched to the clock after change,
external main system clock input
can be disabled (MSTOP = 1).
External subsystem
clock
Enabling input of external clock from the
EXCLKS pin
• OSCSELS = 1, EXCLKS = 1, XTSTOP = 0

Renesas RL78/G1H Specifications

General

Brand	Renesas
Model	RL78/G1H
Category	Microcontrollers
Language	English