4.1.2 Multi-Voltage I/O

The AVR64DD32 Curiosity Nano MCU has support for Multi-Voltage I/O (MVIO). AVR64DD32 MVIO pins are connected to the edge connector at PC0-PC3. MVIO pins are capable of normal I/O-pin behavior.

MVIO can be configured in one of two supply modes:
  • Single-Supply mode: All I/O pins, including MVIO-capable pins, are powered at the same voltage level. VCC_TARGET needs to be connected to VDDIO2
  • Dual-Supply mode: MVIO-capable pins may be powered at a different voltage level than VCC_TARGET
Warning: The absolute maximum voltage for the AVR64DD32 is 5.5V. Applying a higher voltage may cause permanent damage to the board.

By default AVR64DD32 Curiosity Nano board is configured for Dual-Supply mode with VCC_TARGET as the VDDIO2 supply voltage. Some hardware modifications are required to use an external power supply.

Warning: Before doing any hardware modifications, make sure the board is disconnected from the USB and/or external power.
  • Disconnect resistor R201 connecting VDDIO2 to VCC_TARGET
  • Connect a new power supply to VDDIO2 and ground at J217
  • J217 does not have reverse polarity protection. Make sure to match the polarity between the power supply and J217. Positive polarity to J217-pin 1 and negative polarity to J217-pin 2

Resistor R201, VDDIO2 and J217 can be seen in Figure 4-2.

Figure 4-2. MVIO and VDDIO2 Connections
Warning: Applying an external voltage to the VDDIO2 pin without removing resistor R201 may cause permanent damage to the board.
Warning: J217 does not have reverse polarity protection. Applying voltage to the wrong pin may cause permanent damage to the board.