NXP Semiconductors K22F series, Reference Manual, Page: 546 / 1407

MCG_C2 field descriptions (continued)
Field Description
00 Encoding 0 — Low frequency range selected for the crystal oscillator .
01 Encoding 1 — High frequency range selected for the crystal oscillator .
1X Encoding 2 — Very high frequency range selected for the crystal oscillator .
3
HGO
High Gain Oscillator Select
Controls the crystal oscillator mode of operation. See the Oscillator (OSC) chapter for more details.
0 Configure crystal oscillator for low-power operation.
1 Configure crystal oscillator for high-gain operation.
2
EREFS
External Reference Select
Selects the source for the external reference clock. See the Oscillator (OSC) chapter for more details.
0 External reference clock requested.
1 Oscillator requested.
1
LP
Low Power Select
Controls whether the FLL or PLL is disabled in BLPI and BLPE modes. In FBE or PBE modes, setting this
bit to 1 will transition the MCG into BLPE mode; in FBI mode, setting this bit to 1 will transition the MCG
into BLPI mode. In any other MCG mode, LP bit has no affect.
0 FLL or PLL is not disabled in bypass modes.
1 FLL or PLL is disabled in bypass modes (lower power)
0
IRCS
Internal Reference Clock Select
Selects between the fast or slow internal reference clock source.
0 Slow internal reference clock selected.
1 Fast internal reference clock selected.
1. A value for FCFTRIM is loaded during reset from a factory programmed location.
25.3.3 MCG Control 3 Register (MCG_C3)
Address: 4006_4000h base + 2h offset = 4006_4002h
Bit 7 6 5 4 3 2 1 0
Read
SCTRIM
Write
Reset x* x* x* x* x* x* x* x*
* Notes:
x = Undefined at reset. •
MCG_C3 field descriptions
Field Description
SCTRIM Slow Internal Reference Clock Trim Setting
SCTRIM
1
controls the slow internal reference clock frequency by controlling the slow internal reference
clock period. The SCTRIM bits are binary weighted, that is, bit 1 adjusts twice as much as bit 0. Increasing
the binary value increases the period, and decreasing the value decreases the period.
Memory Map/Register Definition
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
546 NXP Semiconductors