NXP Semiconductors K22F series, Reference Manual, Page: 559 / 1407

Table 25-3. MCG modes of operation (continued)
Mode Description
In FEE mode, MCGOUTCLK is derived from the FLL clock (DCOCLK) that is controlled by the
external reference clock. The FLL loop will lock the DCO frequency to the FLL factor, as selected by
C4[DRST_DRS] and C4[DMX32] bits, times the external reference frequency, as specified by
C1[FRDIV] and C2[RANGE]. See the C4[DMX32] bit description for more details. In FEE mode, the
PLL is disabled in a low-power state unless C5[PLLCLKEN] is set .
FLL Bypassed Internal
(FBI) FLL bypassed internal (FBI) mode is entered when all the following conditions occur:
• 01 is written to C1[CLKS].
• 1 is written to C1[IREFS].
• 0 is written to C6[PLLS]
• 0 is written to C2[LP].
In FBI mode, the MCGOUTCLK is derived either from the slow (32 kHz IRC) or fast (4 MHz IRC)
internal reference clock, as selected by the C2[IRCS] bit. The FLL is operational but its output is not
used. This mode is useful to allow the FLL to acquire its target frequency while the MCGOUTCLK is
driven from the C2[IRCS] selected internal reference clock. The FLL clock (DCOCLK) is controlled
by the slow internal reference clock, and the DCO clock frequency locks to a multiplication factor, as
selected by C4[DRST_DRS] and C4[DMX32] bits, times the internal reference frequency. See the
C4[DMX32] bit description for more details. In FBI mode, the PLL is disabled in a low-power state
unless C5[PLLCLKEN] is set .
FLL Bypassed External
(FBE) FLL bypassed external (FBE) mode is entered when all the following conditions occur:
• 10 is written to C1[CLKS].
• 0 is written to C1[IREFS].
• C1[FRDIV] must be written to divide external reference clock to be within the range of 31.25
kHz to 39.0625 kHz.
• 0 is written to C6[PLLS].
• 0 is written to C2[LP].
In FBE mode, the MCGOUTCLK is derived from the OSCSEL external reference clock. The FLL is
operational but its output is not used. This mode is useful to allow the FLL to acquire its target
frequency while the MCGOUTCLK is driven from the external reference clock. The FLL clock
(DCOCLK) is controlled by the external reference clock, and the DCO clock frequency locks to a
multiplication factor, as selected by C4[DRST_DRS] and C4[DMX32] bits, times the divided external
reference frequency. See the C4[DMX32] bit description for more details. In FBE mode, the PLL is
disabled in a low-power state unless C5[PLLCLKEN] is set .
PLL Engaged External
(PEE) PLL Engaged External (PEE) mode is entered when all the following conditions occur:
• 00 is written to C1[CLKS].
• 0 is written to C1[IREFS].
• 1 is written to C6[PLLS].
In PEE mode, the MCGOUTCLK is derived from the output of PLL which is controlled by a external
reference clock. The PLL clock frequency locks to a multiplication factor, as specified by its
corresponding VDIV, times the selected PLL reference frequency, as specified by its corresponding
PRDIV. The PLL's programmable reference divider must be configured to produce a valid PLL
reference clock. The FLL is disabled in a low-power state.
PLL Bypassed External
(PBE) PLL Bypassed External (PBE) mode is entered when all the following conditions occur:
• 10 is written to C1[CLKS].
Table continues on the next page...
Chapter 25 Multipurpose Clock Generator (MCG)
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
NXP Semiconductors 559