CHAPTER 5 CLOCK GENERATOR
Preliminary User’s Manual U19014EJ1V0UD
110
Table 5-4. CPU Clock Transition and SFR Register Setting Examples (3/3)
(5) HALT mode (D) set while CPU is operating with high-speed system clock (C)
Status Transition
Setting
(C)
→
(D)
Executing HALT instruction
(6) STOP mode (E) set while CPU is operating with high-speed system clock (C)
(Setting sequence)
Status Transition
Setting
(C)
→
(E)
Stopping peripheral functions that
cannot operate in STOP mode
Executing STOP instruction
Remark
(A) to (E) in Table 5-4 correspond to (A) to (E) in Figure 5-14.
5.6.7 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 5-5. Changing CPU Clock
CPU Clock
Before Change
After Change
Condition Before Change
Processing After Change
X1 clock
Stabilization of X1 oscillation
•
MSTOP = 0, OSCSEL = 1, EXCLK = 0
•
After elapse of oscillation stabilization time
Internal high-
speed oscillation
clock
External main
system clock
Enabling input of external clock from EXCLK
pin
•
MSTOP = 0, OSCSEL = 1, EXCLK = 1
•
Internal high-speed oscillator can be
stopped (RSTOP = 1).
•
Clock supply to CPU is stopped for 5
µ
s
(MIN.) after AMPH has been set to 1.
X1 clock
X1 oscillation can be stopped (MSTOP = 1).
External main
system clock
Internal high-
speed oscillation
clock
Oscillation of internal high-speed oscillator
•
RSTOP = 0
External main system clock input can be
disabled (MSTOP = 1).
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