Chapter 21
Multipurpose Clock Generator (MCG)
21.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances, see the chip configuration information.
The multipurpose clock generator (MCG) module provides several clock source choices
for the MCU. The module contains a frequency-locked loop (FLL). The FLL is
controllable by either an internal or an external reference clock. The module can select
either of the FLL orthe internal or external reference clocks as a source for the MCU
system clock. The MCG operates in conjuction with a crystal oscillator, which allows an
external crystal, ceramic resonator, or another external clock source to produce the
external reference clock.
21.1.1 Features
Key features of the MCG module are:
• Frequency-locked loop (FLL):
• Digitally-controlled oscillator (DCO)
• DCO frequency range is programmable for up to four different frequency ranges.
• Option to program and maximize DCO output frequency for a low frequency
external reference clock source.
• Option to prevent FLL from resetting its current locked frequency when
switching clock modes if FLL reference frequency is not changed.
KL02 Sub-Family Reference Manual, Rev. 2.1, July 2013
Freescale Semiconductor, Inc.
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