Datasheet

Register 14: GPIO Open Drain Select (GPIOODR), offset 0x50C
The GPIOODR register is the open drain control register. Setting a bit in this register enables the
open drain configuration of the corresponding GPIO pad. When open drain mode is enabled, the
corresponding bit should also be set in the GPIO Digital Enable (GPIODEN) register (see page 320).
Corresponding bits in the drive strength registers (GPIODR2R, GPIODR4R, GPIODR8R, and
GPIOSLR ) can be set to achieve the desired rise and fall times. The GPIO acts as an open-drain
input if the corresponding bit in the GPIODIR register is cleared. If open drain is selected while the
GPIO is configured as an input, the GPIO will remain an input and the open-drain selection has no
effect until the GPIO is changed to an output.
When using the I
2
C module, in addition to configuring the pin to open drain, the GPIO Alternate
Function Select (GPIOAFSEL) register bits for the I
2
C clock and data pins should be set to 1 (see
examples in “Initialization and Configuration” on page 298).
GPIO Open Drain Select (GPIOODR)
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 0x50C
Type R/W, reset 0x0000.0000
16171819202122232425262728293031
reserved
ROROROROROROROROROROROROROROROROType
0000000000000000Reset
0123456789101112131415
ODEreserved
R/WR/WR/WR/WR/WR/WR/WR/WROROROROROROROROType
0000000000000000Reset
DescriptionResetTypeNameBit/Field
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.
0x00ROreserved31:8
Output Pad Open Drain Enable
The ODE values are defined as follows:
DescriptionValue
Open drain configuration is disabled.0
Open drain configuration is enabled.1
0x00R/WODE7:0
June 18, 2012316
Texas Instruments-Production Data
General-Purpose Input/Outputs (GPIOs)
NRND: Not recommended for new designs.