upd78f0124m6gba1-8et Renesas Electronics Corporation., upd78f0124m6gba1-8et Datasheet - Page 125

• Manufacturer Part Number: upd78f0124m6gba1-8et
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

5.8 Clock Switching Flowchart and Register Setting
5.8.1 Switching from internal oscillation clock to X1 input clock
Internal oscillation
Note Check the oscillation stabilization wait time of the X1 oscillator after reset release using the OSTC register
clock operation
value after reset
Register initial
X1 input clock
operation
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 by interrupt during X1 input clock operation.
Figure 5-14. Switching from Internal Oscillation Clock to X1 Input Clock (Flowchart)
Internal oscillation
X1 oscillation stabilization
(dividing set PCC)
clock operation
time has not elapsed
CHAPTER 5 CLOCK GENERATOR
X1 input clock operation
User’s Manual U16315EJ3V1UD
After reset release
Each processing
OSTS = 05H
OSTC check
OSTC = 00H
MCM = 00H
MOC = 00H
PCC setting
MCM.0 ← 1
RCM = 00H
PCC = 00H
X1 oscillation stabilization time has elapsed
Note
Note
; f
; Internal oscillation
; Internal oscillation clock operation
; X1 oscillation
; Oscillation stabilization time status register
; Oscillation stabilization time f
CPU
; X1 oscillation stabilization time status check
MCM.1 (MCS) is changed from 0 to 1
= f
R
XP
/2
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