Clock name
Description
Core clock
MCGOUTCLK divided by OUTDIV1 clocks the ARM Cortex-
M4 core
Platform clock
MCGOUTCLK divided by OUTDIV1, clocks the crossbar
switch and NVIC.
System clock
MCGOUTCLK divided by OUTDIV1, clocks the bus masters
directly. In addition, this clock is used for UART0 and UART1.
Bus clock
MCGOUTCLK divided by OUTDIV2 clocks the bus slaves
and peripheral (excluding memories)
Flash clock
MCGOUTCLK divided by OUTDIV4 clocks the flash memory
MCGIRCLK
MCG output of the slow or fast internal reference clock
MCGFFCLK
MCG output of the slow internal reference clock or a divided
MCG external reference clock.
MCGOUTCLK
MCG output of either IRC, MCGFLLCLK , MCGPLLCLK or
MCG's external reference clock that sources the core,
system, bus, and flash clock. It is also an option for the
debug trace clock.
MCGFLLCLK
MCG output of the FLL. MCGFLLCLK may clock some
modules.
MCGPLLCLK
MCG output of the PLL. MCGFLLCLK or MCGPLLCLK may
clock some modules.
IRC48MCLK
Internal 48 MHz oscillator that can be used as a reference to
the MCG and also may clock some on-chip modules.
OSCCLK
System oscillator output of the internal oscillator or sourced
directly from EXTAL
OSCERCLK
System oscillator output sourced from OSCCLK that may
clock some on-chip modules. Dividable by 1, 2, 4, or 8.
OSC32KCLK
System oscillator 32kHz output
ERCLK32K
Clock source for some modules that is chosen as
OSC32KCLK or the RTC clock.
RTC clock
RTC oscillator output for the RTC module
LPO
PMC 1kHz output
5.4.1 Device clock summary
The following table provides more information regarding the on-chip clocks.
Chapter 5 Clock Distribution
K22F Sub-Family Reference Manual , Rev. 3, 7/2014
Freescale Semiconductor, Inc.
149
