![Texas Instruments SimpleLink Ethernet MSP432E401Y Technical Reference Manual Download Page 1229](http://html1.mh-extra.com/html/texas-instruments/simplelink-ethernet-msp432e401y/simplelink-ethernet-msp432e401y_technical-reference-manual_10955781229.webp)
GPIO Registers
1229
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
General-Purpose Input/Outputs (GPIOs)
17.5.22 GPIOPCTL Register (Offset = 0x52C) [reset = X]
GPIO Port Control (GPIOPCTL)
The GPIOPCTL register is used in conjunction with the GPIOAFSEL register and selects the specific
peripheral signal for each GPIO pin when using the alternate function mode. Most bits in the GPIOAFSEL
register are cleared on reset, therefore most GPIO pins are configured as GPIOs by default. When a bit is
set in the GPIOAFSEL register, the corresponding GPIO signal is controlled by an associated peripheral.
The GPIOPCTL register selects one out of a set of peripheral functions for each GPIO, providing
additional flexibility in signal definition. For information on the defined encodings for the bit fields in this
register, refer to . The reset value for this register is 0x00000000 for GPIO ports that are not listed in the
table below.
NOTE:
If a particular input signal to a peripheral is assigned to two different GPIO port pins, the
signal is assigned to the port with the lowest letter and the assignment to the higher letter
port is ignored. If a particular output signal from a peripheral is assigned to two different
GPIO port pins, the signal will output to both pins. Assigning an output signal from a
peripheral to two different GPIO pins is not recommended.
The table below shows special consideration GPIO pins. Most GPIO pins are configured as GPIOs and
high-impedance by default (GPIOAFSEL = 0, GPIODEN = 0, GPIOPDR = 0, GPIOPUR = 0, and
GPIOPCTL = 0). Special consideration pins may be programed to a nonGPIO function or may have
special commit controls out of reset. In addition, a Power-On-Reset (POR) returns these GPIO to their
original special consideration state.
(1)
This pin is configured as a GPIO by default but is locked and can only be reprogrammed by unlocking the pin in the GPIOLOCK
register and uncommitting it by setting the GPIOCR register.
Table 17-32. GPIO Pins With Special Considerations
GPIO Pins
Default Reset
State
GPIOAFSEL
GPIODEN
GPIOPDR
GPIOPUR
GPIOPCTL
GPIOCR
PC[3:0]
JTAG/SWD
1
1
0
1
0x1
0
PD[7]
GPIO
(1)
0
0
0
0
0x0
0
PE[7]
GPIO
(1)
0
0
0
0
0x0
0
The GPIO commit control registers provide a layer of protection against accidental programming of critical
hardware signals including the GPIO pins that can function as JTAG/SWD signals and the NMI signal. The
commit control process must be followed for these pins, even if they are programmed as alternate
functions other than JTAG/SWD or NMI; see
NOTE:
If the device fails initialization during reset, the hardware toggles the TDO output as an
indication of failure. Thus, during board layout, designers should not designate the TDO pin
as a GPIO in sensitive applications where the possibility of toggling could affect the design.