On the ConnectCore 6UL system-on-module:
Many of the i.MX6UL GPIOs are available at the system-on-module, multiplexed with other functions (labeled GPIOx_IOy where x is the port and y is the GPIO pin). See Hardware reference manuals for information about GPIO pins and their multiplexed functionality.
Eight MCA GPIO pins are available (labeled MCA_IOx where x is the GPIO pin).
On the ConnectCore 6UL SBC Pro board, an I/O Expander chip features up to 39 GPIO pins (multiplexed with Analog-to-Digital Converter (ADC) functionality). See I/O Expander GPIO for additional information on I/O Expander GPIOs. The GPIO connector allows direct access to several i.MX6UL GPIOs, MCA GPIOs, and I/O Expander GPIOs.
On the ConnectCore 6UL SBC Express, the expansion connector allows direct access to several i.MX6UL GPIOs and MCA GPIOs.
On the ConnectCore 6UL SBC Express and SBC Pro boards, GPIOs are used for many purposes, such as:
Power enable line for transceivers
Reset line for controllers
LCD backlight control