NXP Semiconductors KL25 Series - MCG Status and Control Register (MCG_SC)

MCG_S field descriptions (continued)
Field Description
0 Source of internal reference clock is the slow clock (32 kHz IRC).
1 Source of internal reference clock is the fast clock (4 MHz IRC).
24.3.8 MCG Status and Control Register (MCG_SC)
Address: 4006_4000h base + 8h offset = 4006_4008h
Bit 7 6 5 4 3 2 1 0
Read
ATME ATMS
ATMF
FLTPRSRV FCRDIV
LOCS0
Write
Reset
0 0 0 0 0 0 1 0
MCG_SC field descriptions
Field Description
7
ATME
Automatic Trim Machine Enable
Enables the Auto Trim Machine to start automatically trimming the selected Internal Reference Clock.
NOTE: ATME deasserts after the Auto Trim Machine has completed trimming all trim bits of the IRCS
clock selected by the ATMS bit.
Writing to C1, C3, C4, and SC registers or entering Stop mode aborts the auto trim operation and clears
this bit.
0 Auto Trim Machine disabled.
1 Auto Trim Machine enabled.
6
ATMS
Automatic Trim Machine Select
Selects the IRCS clock for Auto Trim Test.
0 32 kHz Internal Reference Clock selected.
1 4 MHz Internal Reference Clock selected.
5
ATMF
Automatic Trim Machine Fail Flag
Fail flag for the Automatic Trim Machine (ATM). This bit asserts when the Automatic Trim Machine is
enabled, ATME=1, and a write to the C1, C3, C4, and SC registers is detected or the MCG enters into any
Stop mode. A write to ATMF clears the flag.
0 Automatic Trim Machine completed normally.
1 Automatic Trim Machine failed.
4
FLTPRSRV
FLL Filter Preserve Enable
This bit will prevent the FLL filter values from resetting allowing the FLL output frequency to remain the
same during clock mode changes where the FLL/DCO output is still valid. (Note: This requires that the
FLL reference frequency to remain the same as what it was prior to the new clock mode switch. Otherwise
FLL filter and frequency values will change.)
0 FLL filter and FLL frequency will reset on changes to currect clock mode.
1 Fll filter and FLL frequency retain their previous values during new clock mode change.
Table continues on the next page...
Memory Map/Register Definition
KL25 Sub-Family Reference Manual, Rev. 3, September 2012
380 Freescale Semiconductor, Inc.