SNIU028D February 2016 – September 2020 UCD3138 , UCD3138064 , UCD3138064A , UCD3138128 , UCD3138A , UCD3138A64
Majority of the pins in UCD3138 can be configured to serve as a general purpose input or output pin (GPIO). The only pins that can not be configured as GPIO pins are the Supply pins, Ground pins, ADC-12 analog input pins, EADC analog input pins and RESET pin.
All digital pins, with the exception of RESET pin, can be configured as GPIOs. There are two ways to configure and use the digital pins as GPIO pins:
This document explains how to use Global I/O registers in order to:
Specific information regarding access of GPIO pins through peripherals localized to those pins can be found in the respective UCD3138 Programmer’s manual covering the peripheral.
In case interaction with a GPIO pin is time critical, GPIO usage via local peripheral settings may be advantageous. In other words interaction with some of the GPIO pins via Global I/O control registers is slower than interacting with the same GPIO pin via local peripheral settings.
As previously mentioned, in the different package options of UCD3138 several I/O functions are multiplexed and routed toward a single physical pin. I/O Mux Control register may be used in order to choose a single specific functionality that is desired to be assigned to a physical device pin for the application.
Please note, Global IO naming and assignment is tied to a specific I/O pin and has a one-to-one relationship with the normal function of each I/O pin. Therefore configuration of a pin functionality using the IOMUX register will not affect its GPIO assignment.
For example, if TCK pin is configured by IOMUX to serve as PWM-0, then the bit