MC80F0424 Datasheet, PDF (104/135 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS

MC80F0424/0432/0448
Preliminary
Main freq. clock
(X_IN pin)
Sub freq. clock
(SX_IN pin)
Operation clock
Main-clock operation
Changed to the Sub-clock
SCMR ← XXXX X010_B
Turn off main clock
SCMR.2 bit HIGH
Sub-clock operation
(a) Main active mode → Sub active mode 1 → Sub active mode 2
Main freq. clock
(X_IN pin)
Sub freq. clock
(SX_IN pin)
Operation clock
Stabilizing Time > 20ms
Sub-clock operation
Main-clock operation
Changed to the Transition
SCMR.2 bit LOW
Changed to the Main-clock
SCMR ← XXXX X000_B
or XXXX X001_B
(b) Sub active mode 2 → Sub active mode 1 → Main active mode
Figure 20-2 System Clock Switching Timing
100
MAR. 2005 Ver 0.2