1.3 I/O Pin Module

The I/O Pin module includes an I/O multiplexer that allows various device functions to be assigned to the multifunction pins. The MCP2222 configuration utility can be used to configure these pin functions.

The multifunction I/O pins support the following configurations:

• GPIOx — An I/O pin can be configured as a general-purpose digital input or output
• ALRTx — One of four I/O pins can be configured as an alert or interrupt input. These inputs can wake the MCP2222 and trigger an interrupt event to the USB host when remote wake-up is enabled.
• USBSPND — Indicates the USB suspend state
• USBCFG — Indicates USB configuration status
• CLKO — Provides a digital clock output. The factory-default frequency is 4 MHz.
• RTS — UART Request to Send output
• CTS — UART Clear to Send input
• RXA — Indicates UART receive activity
• TXA — Indicates UART transmit activity
• I2CA — Indicates I²C bus activity
• SPIA — Indicates SPI bus activity
• I2CTO — Indicates an I²C clock low timeout condition
• CSx — Up to four I/O pins can be configured as SPI chip-select outputs

Input pins include an internal pull-up option, which can be enabled or disabled. Output pins support an open-drain feature that can be enabled or disabled, except for the CLKO and CSx functions.