Arcade Machine: 5V or 3V3 for button wiring

[NivagSwerdna]

This is a really basic question!

I have an arcade table I am restoring and planning to replace the control PCB with a FPGA based solution.  The FPGA has many 3V3 i/o pins which are not 5V compatible.

Previously the PCB operated (primarily) at 5V so the wiring to the buttons was that the button was grounded on one side and then the other side came back to a wire that ended up on the PCB at a 8255 (Intel old style Peripheral Interface) with 1kR pull-up and a 220R current limiting resistor.

I'm planning on using a trio SN74HC165 to provide sufficient lines for the buttons... just wondering if I could get away with operating at 3V3 or I should operate the shift registers and buttons at 5V and level shift back down to 3V3?

The total round trip distance to the furthest button is around 150cm

What do I need to consider?  R of wire, immunity to noise?

[Ian.M]

You also need to consider wetting current for the switches unless they have gold plated or carbon contacts.   A rough rule of thumb for reliable switch sensing is to pass 10mA through each switch with 10V (or greater) across each when open.   That ensures there is enough voltage to break down light oxide films and enough current for the contacts to be self-cleaning.   5mA and 5V was probably enough for good quality switches.

The easy option would be to level shift the SPI interface and run the shift registers at 5V, keeping the 1K pullups and any existing signal conditioning circuits.