May I not supply voltage to VCCIO during power up and configuration?

Hi,

We have to supply VCCIO. If VCCIO is not powered, configuration will fail. The POR circuitry keeps the Cyclone V device in the reset state until the power supply outputs are within the recommended operating range.

1. The output buffers are tri-stated during system power up or power down,All user I/O pins are tri-stated during configuration.
2. The POR circuitry monitors the voltage level of the power supplies and keeps the I/O pins tri-stated until the device is in user mode.

Reference page 142 & 318.

https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/cyclone-v/cv_5v2.pdf

Let me know if you need any further assistance.

Best Regards,

Anand