(Edit: I think the story below was for the original Playstation, with it's action-replay expansion port module. Should still have it somewhere in storage )
I also remember it having a serial or parallel port (at least the european Action Replay did), which you could hook upto a PC and with some debugging-software, do things like runtime memory manipulation, breakpoints and other nice debugging tools.
I think you could even run your own (small) binaries by sending them to the cartridge/addon, but this was ~20+ years ago, so the details lack me.
I also remember it having a serial or parallel port (at least the european Action Replay did), which you could hook upto a PC and with some debugging-software, do things like runtime memory manipulation, breakpoints and other nice debugging tools.
I think you could even run your own (small) binaries by sending them to the cartridge/addon, but this was ~20+ years ago, so the details lack me.