LM3S6965 Microcontroller
Register 15: GPIO Pull-Up Select (GPIOPUR), offset 0x510
The GPIOPUR registeristhepull-upcontrolregister. Whenabitissetto1,itenablesaweakpull-up resistor on the corresponding GPIO signal. Setting a bit in GPIOPUR automatically clears the corresponding bit in the GPIO Pull-Down Select (GPIOPDR) register (see page 200).
GPIO Pull-Up Select (GPIOPUR)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
Offset 0x510
Type R/W, reset -
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31 |
30 |
29 |
28 |
27 |
26 |
25 |
24 |
23 |
22 |
21 |
20 |
19 |
18 |
17 |
16 |
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reserved |
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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 |
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15 |
14 |
13 |
12 |
11 |
10 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
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reserved |
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PUE |
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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 |
- |
- |
- |
- |
- |
- |
- |
- |
Bit/Field |
Name |
Type |
Reset |
Description |
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31:8 |
reserved |
RO |
0x00 |
Software should not rely on the value of a reserved bit. To provide |
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compatibility with future products, the value of a reserved bit should be |
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preserved across a read-modify-write operation. |
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7:0 |
PUE |
R/W |
- |
Pad Weak Pull-Up Enable |
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A write of 1 to GPIOPDR[n] clears the corresponding GPIOPUR[n] |
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enables. The change is effective on the second clock cycle after the |
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write. |
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Note: |
The default reset value for the GPIOAFSEL, GPIOPUR, and |
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GPIODEN registers are 0x0000.0000 for all GPIO pins, with |
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theexceptionofthefiveJTAG/SWDpins(PB7 and PC[3:0]). |
These five pins default to JTAG/SWD functionality. Because ofthis,thedefaultresetvalueoftheseregistersforGPIOPort B is 0x0000.0080 while the default reset value for Port C is 0x0000.000F.
November 16, 2008 |
199 |
Preliminary
General-Purpose Input/Outputs (GPIOs)
Register 16: GPIO Pull-Down Select (GPIOPDR), offset 0x514
The GPIOPDR register is the pull-down control register. When a bit is set to 1, it enables a weak pull-downresistoronthecorrespondingGPIOsignal. Settingabitin GPIOPDR automaticallyclears the corresponding bit in the GPIO Pull-Up Select (GPIOPUR) register (see page 199).
GPIO Pull-Down Select (GPIOPDR)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
Offset 0x514
Type R/W, reset 0x0000.0000
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31 |
30 |
29 |
28 |
27 |
26 |
25 |
24 |
23 |
22 |
21 |
20 |
19 |
18 |
17 |
16 |
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reserved |
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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 |
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15 |
14 |
13 |
12 |
11 |
10 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
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reserved |
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PDE |
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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 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Bit/Field |
Name |
Type |
Reset |
Description |
31:8 |
reserved |
RO |
0x00 |
Software should not rely on the value of a reserved bit. To provide |
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compatibility with future products, the value of a reserved bit should be |
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preserved across a read-modify-write operation. |
7:0 |
PDE |
R/W |
0x00 |
Pad Weak Pull-Down Enable |
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A write of 1 to GPIOPUR[n] clears the corresponding GPIOPDR[n] |
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enables. The change is effective on the second clock cycle after the |
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write. |
200 |
November 16, 2008 |
Preliminary
LM3S6965 Microcontroller
Register 17: GPIO Slew Rate Control Select (GPIOSLR), offset 0x518
The GPIOSLR register is the slew rate control register. Slew rate control is only available when using the 8-mA drive strength option via the GPIO 8-mA Drive Select (GPIODR8R) register (see page 197).
GPIO Slew Rate Control Select (GPIOSLR)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
Offset 0x518
Type R/W, reset 0x0000.0000
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31 |
30 |
29 |
28 |
27 |
26 |
25 |
24 |
23 |
22 |
21 |
20 |
19 |
18 |
17 |
16 |
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reserved |
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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 |
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15 |
14 |
13 |
12 |
11 |
10 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
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reserved |
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SRL |
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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 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
Bit/Field |
Name |
Type |
Reset |
Description |
31:8 |
reserved |
RO |
0x00 |
Software should not rely on the value of a reserved bit. To provide |
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compatibility with future products, the value of a reserved bit should be |
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preserved across a read-modify-write operation. |
7:0 |
SRL |
R/W |
0x00 |
Slew Rate Limit Enable (8-mA drive only) |
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The SRL values are defined as follows: |
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Value Description |
0 Slew rate control disabled.
1 Slew rate control enabled.
November 16, 2008 |
201 |
Preliminary
General-Purpose Input/Outputs (GPIOs)
Register 18: GPIO Digital Enable (GPIODEN), offset 0x51C
Note: Pins configured as digital inputs are Schmitt-triggered.
The GPIODEN register is the digital enable register. By default, with the exception of the GPIO signalsusedforJTAG/SWDfunction,allotherGPIOsignalsareconfiguredoutofresettobeundriven (tristate). Their digital function is disabled; they do not drive a logic value on the pin and they do not allow the pin voltage into the GPIO receiver. To use the pin in a digital function (either GPIO or alternate function), the corresponding GPIODEN bit must be set.
GPIO Digital Enable (GPIODEN)
GPIO Port A base: 0x4000.4000
GPIO Port B base: 0x4000.5000
GPIO Port C base: 0x4000.6000
GPIO Port D base: 0x4000.7000
GPIO Port E base: 0x4002.4000
GPIO Port F base: 0x4002.5000
GPIO Port G base: 0x4002.6000
Offset 0x51C
Type R/W, reset -
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31 |
30 |
29 |
28 |
27 |
26 |
25 |
24 |
23 |
22 |
21 |
20 |
19 |
18 |
17 |
16 |
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reserved |
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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 |
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15 |
14 |
13 |
12 |
11 |
10 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
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reserved |
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DEN |
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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 |
- |
- |
- |
- |
- |
- |
- |
- |
Bit/Field |
Name |
Type |
Reset |
Description |
31:8 |
reserved |
RO |
0x00 |
Software should not rely on the value of a reserved bit. To provide |
|
|
|
|
compatibility with future products, the value of a reserved bit should be |
|
|
|
|
preserved across a read-modify-write operation. |
7:0 |
DEN |
R/W |
- |
Digital Enable |
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The DEN values are defined as follows: |
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Value Description |
0 Digital functions disabled.
1 Digital functions enabled.
Note: The default reset value for the GPIOAFSEL, GPIOPUR,andGPIODEN registersare0x0000.0000 for all GPIO pins, with the exception of the five JTAG/SWDpins(PB7 and PC[3:0]). Thesefivepins default to JTAG/SWD functionality. Because of this, the default reset value of these registers for GPIO Port B is 0x0000.0080 while the default reset value for Port C is 0x0000.000F.
202 |
November 16, 2008 |
Preliminary