NXP Semiconductors K22F series, Reference Manual, Page: 153 / 1407

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)
FlexBus clock MCGOUTCLK divided by OUTDIV3 clocks the external
FlexBus interface
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, FlexBus, 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.
Table 5-1. Clock Summary
Clock name High Speed Run
mode
clock frequency
Run mode
clock frequency
VLPR mode
clock frequency
Clock source Clock is disabled
when…
MCGOUTCLK Up to 120 MHz Up to 120 MHz Up to 4 MHz MCG In all stop modes
except for partial
Table continues on the next page...
Chapter 5 Clock Distribution
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
NXP Semiconductors 153