CHAPTER 5 CLOCK GENERATOR
Preliminary User’s Manual U16315EJ1V0UD
124
5.8 Clock Switching Flowchart and Register Setting
5.8.1 Switching from Ring-OSC clock to X1 input clock
Figure 5-14. Switching from Ring-OSC Clock to X1 Input Clock (Flowchart)
; f
CPU
= f
R
; Ring-OSC oscillation
; Ring-OSC clock operation
; X1 oscillation
; Oscillation stabilization time status register
; Oscillation stabilization time f
XP
/2
16
MCM.1 (MCS) is changed from 0 to 1
; X1 oscillation stabilization time status check
X1 oscillation stabilization time has elapsed
X1 oscillation stabilization
time has not elapsed
PCC = 00H
RCM = 00H
MCM = 00H
MOC = 00H
OSTC = 00H
OSTS = 05H
Note
OSTC check
Note
Each processing
After reset release
PCC setting
MCM.0
←
1
X1 input clock operation
Ring-OSC
clock operation
(dividing set PCC)
Register initial
value after reset
Ring-OSC clock
operation
X1 input clock
operation
Note
Check the
oscillation stabilization wait time of the X1 oscillator after reset release using the OSTC register
and then switch to the X1 input clock operation after the oscillation stabilization wait time has elapsed. The
OSTS register setting is valid only after STOP mode is released during X1 input clock operation.