Yes, they generally recommend using the regulators to protect their boards from uncontrolled voltages sources or power spikes.lupod wrote:When I use the Arduino for debugging, it is powered from USB. Even when not connected to USB, the makers of the Arduino board say "Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it." (https://store.arduino.cc/usa/arduino-uno-rev3)
So when I followed the instructions (with just a little experience with the arduino), I just connected it to USB, and hooked up the signals from the PSX (which was obviously a bad idea because then it's 5V). When connecting 3.3 to IOREF, the Arduino is still powered from USB, but works with a logic level of 3.3V.
However, in our application (board installed in PSX), we have a controlled power source and additionally we know that we need it to be ~3.3V to get the signal levels right. In this case, using the 3.3V pin is exactly the right thing to do.
I don't know how the IOREF pin is supposed to be used but I really recommend not using it for power.
Oh, here's some info for your 5502. It might work!
https://assemblergames.com/threads/ps1- ... ost-945098