LP3971 Datasheet, PDF (21/42 Pages) National Semiconductor (TI) – POWER MANAGEMENT UNIT FOR ADVANCED APPLICATION PROCESSORS

I ²C Register Definitions (Continued)
SYSTEM CONTROL REGISTER (SCR2) 8h’0E
Bit
Designation
Reset Value
7
BBCS
1
6
SEB2
0
5
BPTR
0
4
WUP3_
sense
1
3
2
GPIO2
0
0
SYSTEM CONTROL REGISTER (SCR2) 8h’0E DEFINITIONS
Bit Access
7
R/W
6
R/W
5
R/W
4
R/W
3:2
R/W
1:0
R/W
Name
BBCS
SEB2
BPTR
WUP3_
sense
GPIO2
GPIO1
Description
Sets GPIO1 as control input for Back Up battery charger
0 = Back Up battery Charger GPIO Disabled
1 = Back Up battery Charger GPIO Pin Enabled
PWR_EN soft Low voltage Supply Enabled OR’ed with PWR_EN Pin
0 = Low voltage Supply Output Enabled
1 = Low voltage Supply Output Disabled
Bypass RTC_LDO Output Voltage to LDO1 Output Voltage Tracking
0 = Disabled RTC_LDO1 Tracking enabled
1 = Enabled RTC-LDO1 Tracking disabled
Spare Wakeup control input
0 = Active High
1 = Active Low
Configure direction and output sense of GPIO2 Pin
Data Code
GPIO2
2h’00
Hi-Z
2h’01
Output Low
2h’02
Input
2h’03
Output high
Configure direction and output sense of GPIO1 Pin
Data Code
GPIO1
2h’00
Hi-Z
2h’01
Output Low
2h’02
Input
2h’03
Output high
1
0
GPIO1
0
0
21
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