Abstract: A GPIO includes a transmitter having an output stage connected to the I/O pad and adapted to supply transmit data to an I/O pad in response to output data generated by a low voltage core logic operating within a functional voltage range for transmit operations; a receiver adapted to supply receive data to the low voltage core logic operating within the functional voltage range in response to input data received at the I/O pad for receive operations; a VLV transmitter adapted to supply VLV transmit data to the output stage of the transmitter and not directly to the I/O pad in response to output test data generated by the low voltage core logic; and a VLV receiver adapted to supply VLV receive data to the low voltage core logic operating within a low core supply voltage range in response to input data received from the output stage of the transmitter.