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M0A21/M0A23 Series
May 06, 2022
Page
197
of 746
Rev 1.02
M0
A21
/M
0
A
2
3
SE
RIES
TEC
H
NICAL
RE
FEREN
C
E
M
ANUAL
[19]
Reserved
Reserved.
[18:16]
TMR2SEL
TIMER2 Clock Source Selection
000 = Clock source from external high speed crystal oscillator (HXT).
001 = Clock source from external low speed crystal oscillator (LXT).
010 = Clock source from PCLK1.
011 = Clock source from external clock T2 pin.
101 = Clock source from internal low speed RC oscillator (LIRC).
111 = Clock source from internal high speed RC oscillator (HIRC).
Others = Reserved.
[15]
Reserved
Reserved.
[14:12]
TMR1SEL
TIMER1 Clock Source Selection
000 = Clock source from external high speed crystal oscillator (HXT).
001 = Clock source from external low speed crystal oscillator (LXT).
010 = Clock source from PCLK0.
011 = Clock source from external clock T1 pin.
101 = Clock source from internal low speed RC oscillator (LIRC).
111 = Clock source from internal high speed RC oscillator (HIRC).
Others = Reserved.
[11]
Reserved
Reserved.
[10:8]
TMR0SEL
TIMER0 Clock Source Selection
000 = Clock source from external high speed crystal oscillator (HXT).
001 = Clock source from external low speed crystal oscillator (LXT).
010 = Clock source from PCLK0.
011 = Clock source from external clock T0 pin.
101 = Clock source from internal low speed RC oscillator (LIRC).
111 = Clock source from internal high speed RC oscillator (HIRC).
Others = Reserved.
[7]
Reserved
Reserved.
[6:4]
CLKOSEL
Clock Divider Clock Source Selection
000 = Clock source from external high speed crystal oscillator (HXT).
001 = Clock source from external low speed crystal oscillator (LXT).
010 = Clock source from HCLK.
100 = Clock source from internal low speed RC oscillator (LIRC).
101 = Clock source from internal high speed RC oscillator (HIRC).
Others = Reserved.
[3:2]
WWDTSEL
Window Watchdog Timer Clock Source Selection (Write Protect)
10 = Clock source from HCLK/2048.
11 = Clock source from internal low speed RC oscillator (LIRC).
Others = Reserved.
[1:0]
WDTSEL
Watchdog Timer Clock Source Selection (Write Protect)
01 = Clock source from external low speed crystal oscillator (LXT).
10 = Clock source from HCLK/2048.
11 = Clock source from internal low speed RC oscillator (LIRC).
Others = Reserved.
Note:
This bit is write protected. Refer to the SYS_REGLCTL register. 2. It will be forced to 11 when
CONFIG0[31], CONFIG0[4], CONFIG0[3] are all ones.