Switching From X1 Input Clock To Ring-Osc Clock - NEC 78K0 User Manual

5.8.2 Switching from X1 input clock to Ring-OSC clock

Figure 5-15. Switching from X1 Input Clock to Ring-OSC Clock (Flowchart)
X1 input
clock operation
Ring-OSC
clock operation
Note Required only when "clock can be stopped by software" is selected for Ring-OSC by a mask option.
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CHAPTER 5 CLOCK GENERATOR
Register setting PCC.7 (MCC) = 0
in X1 input PCC.4 (CSS) = 0
clock operation
Yes: RSTOP = 1
RSTOP = 0
Ring-OSC clock operation
User's Manual U16227EJ2V0UD
; X1 oscillation
; X1 input clock or Ring-OSC clock
MCM = 03H ; X1 input clock operation
Note
RCM.0
; Ring-OSC oscillating?
(RSTOP) = 1?
No: RSTOP = 0
MCM0 ← 0
; Ring-OSC clock operation
MCM.1 (MCS) is changed from 1 to 0