Category: Specifications
Tools: Quartus® Prime / Quartus II
Device: MAX®10


The VOD settings for MAX 10 devices are set in the Assignment Editor as follows:

To: tx_out
Assignment name: Programmable Differential Output Voltage (VOD)
Allowed values: 0 (low), 1 (medium), 2 (high)
(The default is 2 (high).)

For details, refer to the document below.
https://www.altera.com/en_US/pdfs/literature/hb/max-10/ug_m10_gpio.pdf
(Search by keyword Programmable VOD.)