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M0A21/M0A23 Series
May 06, 2022
Page
145
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Rev 1.02
M0
A21
/M
0
A
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SE
RIES
TEC
H
NICAL
RE
FEREN
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E
M
ANUAL
This field defines that trim value calculation is based on how many reference clocks.
00 = Trim value calculation is based on average difference in 4 clocks of reference clock.
01 = Trim value calculation is based on average difference in 8 clocks of reference clock.
10 = Trim value calculation is based on average difference in 16 clocks of reference clock.
11 = Trim value calculation is based on average difference in 32 clocks of reference clock.
Note:
For example, if LOOPSEL is set as 00, auto trim circuit will calculate trim value based on the average
frequency difference in 4 clocks of reference clock.
[3:2]
Reserved
Reserved.
[1:0]
FREQSEL
Trim Frequency Selection
This field indicates the target frequency of 48 MHz internal high speed RC oscillator (HIRC) auto trim.
During auto trim operation, if clock error detected with CESTOPEN is set to 1 or trim retry limitation count
reached, this field will be cleared to 00 automatically.
00 = Disable HIRC auto trim function.
01 = Enable HIRC auto trim function and trim HIRC to 48 MHz.
10 = Reserved..
11 = Reserved.