Device Overview
MCF51CN128 Reference Manual
,
Rev. 6
1-12
Freescale Semiconductor
1.4.5
MCG Mode State Diagram
shows the valid state transitions for the MCG. The arrows indicate the permitted mode
Chapter 6, “Multipurpose Clock Generator (MCG)
,” for additional details.
Software must ensure that the system bus frequency is less than 125 kHz and the FLLs are disengaged
prior to switching to BLPE and BLPI modes of operation.
Figure 1-4. MCG Mode State Diagram
Entered from any state
when MCU enters stop
Returns to state that was active
before MCU entered stop, unless
RESET occurs while in stop.
Stop
PLL Bypassed
External (PBE)
PLL Engaged
External (PEE)
FLL Engaged
External (FEE)
FLL Engaged
Internal (FEI)
FLL Bypassed
External (FBE)
FLL Bypassed
Internal (FBI)
Bypassed
Low Power
Internal (BLPI)
Bypassed
Low Power
External (BLPE)
BDM Enabled