Clock Switching Flowchart And Register Setting; Switching From Ring-Osc Clock To High-Speed System Clock - NEC MuPD78F0132H User Manual

5.8 Clock Switching Flowchart and Register Setting

5.8.1 Switching from Ring-OSC clock to high-speed system clock

Figure 5-14. Switching from Ring-OSC Clock to High-Speed System Clock (Flowchart)
Register value
after reset
High-speed system clock
Ring-OSC clock oscillation stabilization
time has not elapsed
operation
Ring-OSC
clock operation
(dividing set PCC)
High-speed system
clock operation
Note Check the oscillation stabilization wait time of the high-speed system clock oscillator after reset release
using the OSTC register and then switch to the high-speed system 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 high-speed system clock operation.
CHAPTER 5 CLOCK GENERATOR
After reset
PCC = 00H
RCM = 00H
MCM = 00H
MOC = 00H
OSTC = 00H
Note
OSTS = 05H
Each processing
Note
OSTC check
High-speed system clock oscillation stabilization time has elapsed
PCC setting
MCM.0 ← 1
High-speed system clock operation
User's Manual U16899EJ2V0UD
; f = f
CPU R
; Ring-OSC oscillation
; Ring-OSC clock operation
; High-speed system clock oscillation
; Oscillation stabilization time status register
; Oscillation stabilization time f
; High-speed system clock oscillation
stabilization time status check
MCM.1 (MCS) is changed from 0 to 1
16
/2
XP
131