GMS81C5108
Main freq. clock
(X pin)
IN
Sub freq. clock
(SX pin)
IN
Operation clock
Main-clock operation
Sub-clock operation
Changed to the Sub-clock
SCMR ← XXXX XX10
B
Turn off main clock
SCMR ← XXXX XX11
B
(a) Main active mode → Sub active mode
Main freq. clock
(X pin)
IN
Stabilizing Time > 60ms
Sub freq. clock
(SX pin)
IN
Operation clock
Sub-clock operation
Main-clock operation
Changed to the Transition
SCMR ← XXXX XX10
B
Changed to the Main-clock
SCMR ← XXXX XX00
B
B
or XXXX XX01
(b) Sub active mode → Main active mode
Figure 10-4 System Clock Switching Timing
38
JUNE 2001 Ver 1.0