19.2 Overview

The MVIO feature allows a subset of the I/O pins to be powered by a different I/O voltage domain than the rest of the I/O pins. This eliminates the need of having external level shifters for communication or control of external components running on a different voltage level. The MVIO-capable I/O pads are supplied by a voltage applied to the VDDIO2 power pin(s), while the regular I/O pins are supplied by the voltage applied to the VDD pin(s).

The MVIO can be configured in one of two supply modes:

• Single-Supply mode, where the MVIO-capable I/O pins are powered at the same voltage level as the non-MVIO capable pins, i.e., V_DD. The user must connect the VDDIO2 pin(s) to the VDD pin(s).
• Dual-Supply mode, where the MVIO-capable I/O pins are supplied by the V_DDIO2 voltage, which may be different from the voltage supplied to the VDD pin(s).

A configuration fuse determines the MVIO supply mode. The loss or gain of power on V_DDIO2 is signaled by a status register bit. This status bit has corresponding interrupt and event functionality.

The MVIO pins are capable of the same digital behavior as regular I/O pins, e.g., GPIO, serial communication (USART, SPI, I²C), or connected to PWM peripherals. The input Schmitt trigger levels are scaled according to the V_DDIO2 voltage, as described in the Electrical Characteristics section of the data sheet.

A divided-down V_DDIO2 voltage is available as input to the ADC.