5V to GPIO while reading

[HollayHorvath]

I just stumbled upon your project while I was planning to build my own EEPROM programmer, excellent project, thank you for it!

However I have a question about the read mode. The 28C256 outputs the Vcc on the data pins while being read which is +5V however the Raspberry Pi GPIO pins are only capable to handle +3.3V. Based on the documentation the 5V can damage the pins or could kill the whole device. Did you experience any issues with it?

What I found on some forums that 5V with some low uA current should be fine, however there was no consensus on what the exact number would be. Do you have some numbers around this possible problem?