NXP Semiconductors freescale KV4 Series, Reference Manual

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Chapter 30
Multipurpose Clock Generator (MCG)
30.1 Introduction
The multipurpose clock generator (MCG) module provides several clock source choices
for the MCU.
The module contains a frequency-locked loop (FLL) and a phase-locked loop (PLL). The
FLL is controllable by either an internal or an external reference clock. The PLL is
controllable by the external reference clock. The module can select either an FLL or PLL
output clock, or a reference clock (internal or external) 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.
30.1.1 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.
• Internal or external reference clock can be used as the FLL source.
• Can be used as a clock source for other on-chip peripherals.
• Phase-locked loop (PLL):
KV4x Reference Manual, Rev. 2, 02/2015
Freescale Semiconductor, Inc.
Preliminary
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