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M0A21/M0A23 Series
May 06, 2022
Page
212
of 746
Rev 1.02
M0
A21
/M
0
A
2
3
SE
RIES
TEC
H
NICAL
RE
FEREN
C
E
M
ANUAL
CONFIG0 (Address = 0x0030_0000)
31
30
29
28
27
26
25
24
CWDTEN[2]
CWDTPDEN
Reserved
CFGXT1
Reserved
CFGRPS
Reserved
23
22
21
20
19
18
17
16
Reserved
CBOV
CBORST
CBODEN
Reserved
15
14
13
12
11
10
9
8
Reserved
ICELOCK
Reserved
CIOINI
RSTEXT
RSTWSEL
7
6
5
4
3
2
1
0
CBS
Reserved
CWDTEN[1:0]
Reserved
LOCK
DFEN
Bits
Description
[31]
CWDTEN[2]
Watchdog Timer Hardware Enable Bit
When the watchdog timer hardware enable function is enabled, the watchdog enable bit WDTEN
(WDT_CTL[7]) and watchdog reset enable bit RSTEN (WDT_CTL[1]) is set to 1 automatically after power
on. The clock source of watchdog timer is force at LIRC and LIRC can’t be disabled in normal operation
mode. However, in Power-down mode, the LIRC may be able to be disabled by setting CWDTPDEN=1
and LIRCEN=0 (CLK_PWRCTL[3]).
CWDTEN[2:0]
is CONFIG0[31][4][3],
011 = WDT hardware enable function is active. WDT clock is always on except chip enters Power- down
mode. When chip enters Power-down mode, WDT clock is always on if CWDTPDEN is 0 or WDT clock
is controlled by LIRCEN (CLK_PWRCTL[3]) if CWDTPDEN is 1. Please refer to bit field description of
CWDTPDEN.
111 = WDT hardware enable function is inactive, WDT clock source only can be changed in this case.
Others = WDT hardware enable function is active. WDT clock is always on.
[30]
CWDTPDEN
Watchdog Clock Power-down Enable Bit
This bit should be used with CWDTEN. When WDT enabled by CWDTEN, user can use this bit to control
WDT wakeup when system is in Power-down mode. If it is necessary to wakeup system by WDT, then
user can set CWDTPDEN=0 to make sure WDT keep working at Power-
down mode. If user don’t want to
wakeup system by WDT, user may just set CWDTPDEN=1 and LIRCEN=0 to let WDT suspend in power
down.
0 = Watchdog Timer clock kept enabled when chip enters power-down.
1 = Watchdog Timer clock is controlled by LIRCEN (CLK_PWRCTL[3]) when the chip enters power-
down.
Note:
This bit only works if CWDTEN[2:0] is set to 011.
[29:28]
Reserved
Reserved.
[27]
CFGXT1
HXT Mode Selection
0 = HXT works as external clock mode. PA.5 is configured as external clock input pin.
1 = HXT works as crystal mode. PA.4 and PA.5 are configured as external high speed crystal(HXT) pins.
Note:
When CFGXT1 = 0, P4.5 MFP should be set as GPIO mode. The DC characteristic of XT1_IN is
the same as GPIO.
[26]
Reserved
Reserved.
[25]
CFGRPS
Reset Pin Selection
0 = Set GPA[3] to GPIO mode.
1 = Set GPA[3] to nReset mode.
[24:23]
Reserved
Reserved.