Pad
Control
Commit
Control
Mode
Control
GPIOAFSEL
Data
Control
Interrupt
Control
MUX
MUX
DEMUX
Digital
I/O
Pad
Identification Registers
GPIOPeriphID0
GPIOPeriphID1
GPIOPeriphID2
GPIOPeriphID3
GPIOPeriphID4
GPIOPeriphID5
GPIOPeriphID6
GPIOPeriphID7
GPIOPCellID0
GPIOPCellID1
GPIOPCellID2
GPIOPCellID3
Pad Input
Pad Output
Enable
GPIOLOCK
GPIOCR
GPIODATA
GPIODIR
GPIOIS
GPIOIBE
GPIOIEV
GPIOIM
GPIORIS
GPIOMIS
GPIOICR
GPIOPUR
GPIOODR
GPIODEN
Alternate Input
Alternate Output
Alternate OutputEnable
Interrupt
GPIO Input
GPIO Output
GPIO OutputEnable
Pad Output
Package I/OPin
MUX
Periph 0
Periph 1
Periph n
Port
Control
GPIOPCTL
GPIOAPSEL
GPIOAMSEL
GPIOCSEL
General-Purpose Input/Output (GPIO)
342
SPRUH22I – April 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
General-Purpose Input/Output (GPIO)
Figure 4-1. Digital I/O Pads
4.1.3.1
Master Control
The M3 GPIO mux is the master, and at boot time, the user needs to allocate which core (M3 or C28)
controls which pin. By default, all pins are assigned to the M3 GPIO mux except Group 2 GPIOs. See
for more information.
To select which core controls a GPIO pin, use the GPIO Core Select (GPIOCSEL) register. If the M3
GPIOs are enabled by the GPIODEN register, the M3 can still monitor any GPIO, even if it is mapped to
the C28 GPIO mux.
4.1.3.2
Data Control
The data control registers allow software to configure the operational modes of the GPIOs. The data
direction register configures the GPIO as an input or an output while the data register either captures
incoming data or drives it out to the pads.
4.1.3.2.1 Data Direction Operation
The GPIO Direction (GPIODIR) register is used to configure each individual pin as an input or output.
When the data direction bit is cleared, the GPIO is configured as an input, and the corresponding data
register bit captures and stores the value on the GPIO port. When the data direction bit is set, the GPIO is
configured as an output, and the corresponding data register bit is driven out on the GPIO port.