LM3S1D26 Datasheet, PDF (417/805 Pages) Texas Instruments – Stellaris® LM3S1D26 Microcontroller

Stellaris^® LM3S1D26 Microcontroller
Register 15: GPIO Pull-Up Select (GPIOPUR), offset 0x510
The GPIOPUR register is the pull-up control register. When a bit is set, a weak pull-up resistor on
the corresponding GPIO signal is enabled. Setting a bit in GPIOPUR automatically clears the
corresponding bit in the GPIO Pull-Down Select (GPIOPDR) register (see page 419). Write access
to this register is protected with the GPIOCR register. Bits in GPIOCR that are cleared prevent writes
to the equivalent bit in this register.
Important: All GPIO pins are configured as GPIOs and tri-stated by default (GPIOAFSEL=0,
GPIODEN=0, GPIOPDR=0, GPIOPUR=0, and GPIOPCTL=0, with the exception of the
pins shown in the table below. A Power-On-Reset (POR) or asserting RST puts the pins
back to their default state.
Table 9-8. GPIO Pins With Non-Zero Reset Values
GPIO Pins
PA[1:0]
PA[5:2]
PB[3:2]
PC[3:0]
Default State
UART0
SSI0
I²C0
JTAG/SWD
GPIOAFSEL GPIODEN GPIOPDR GPIOPUR
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
1
GPIOPCTL
0x1
0x2
0x3
0x1
Note:
The GPIO commit control registers provide a layer of protection against accidental
programming of critical hardware peripherals. Protection is provided for the NMI pin (PB7)
and the four JTAG/SWD pins (PC[3:0]). Writes to protected bits of the GPIO Alternate
Function Select (GPIOAFSEL) register (see page 411), GPIO Pull Up Select (GPIOPUR)
register (see page 417), GPIO Pull-Down Select (GPIOPDR) register (see page 419), and
GPIO Digital Enable (GPIODEN) register (see page 422) are not committed to storage
unless the GPIO Lock (GPIOLOCK) register (see page 424) has been unlocked and the
appropriate bits of the GPIO Commit (GPIOCR) register (see page 425) have been set.
GPIO Pull-Up Select (GPIOPUR)
GPIO Port A (APB) base: 0x4000.4000
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (APB) base: 0x4000.5000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (APB) base: 0x4000.6000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (APB) base: 0x4000.7000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (APB) base: 0x4002.4000
GPIO Port E (AHB) base: 0x4005.C000
Offset 0x510
Type R/W, reset -
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
reserved
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
reserved
PUE
Type RO
RO
RO
RO
RO
RO
RO
RO
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset
0
0
0
0
0
0
0
0
-
-
-
-
-
-
-
-
January 22, 2012
417
Texas Instruments-Production Data