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NUC126
Aug. 08, 2018
Page
543
of 943
Rev 1.03
NUC12
6 S
E
RI
E
S
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CH
NI
CA
L R
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F
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RE
NCE
MA
NUA
L
RTC X32KI Pin Control Register (RTC_LXTICTL)
Register
Offset
R/W
Description
Reset Value
RTC_LXTICTL
0x108
R/W
RTC X32KI Pin Control Register
0x0000_0000
31
30
29
28
27
26
25
24
Reserved
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
Reserved
7
6
5
4
3
2
1
0
Reserved
CTLSEL
DOUT
OPMODE
Bits
Description
[31:4]
Reserved
Reserved.
[3]
CTLSEL
I/O Pin State Backup Selection
When low speed 32 kHz oscillator (LXT) is disabled, X32KO pin can be used as GPIO
PF.1 function. User can program CTLSEL to decide X32KI (PF.1) I/O function is controlled
by system power domain GPIO module or V
BAT
power domain RTC_LXTICTL register.
0 = X32KI (PF.1) pin I/O function is controlled by GPIO module.
1 = X32KI (PF.1) pin I/O function is controlled by OPMODE and DOUT in RTC_LXTICTL
at V
BAT
power domain.
Note:
CTLSEL will be set to 1 automatically by hardware when system power is turned off
and RTC is at normal active state, ACTIVE (RTC_INIT[0]) is 1.
[2]
DOUT
IO Pin Output Data
0 = X32KI (PF.1) will drive low in output mode.
1 = X32KI (PF.1) will drive high in output mode.
[1:0]
OPMODE
I/O Pin Operation Mode
00 = X32KI (PF.1) is in Input mode without pull-up resistor.
01 = X32KI (PF.1) is in Push-pull output mode.
10 = X32KI (PF.1) is in Open-drain output mode.
11 = X32KI (PF.1) is in Input mode with pull-up resistor.