I have yet to see a pinout of the Saturn cart slot. From what I've gathered it seems to have a 16-bit data bus and probably has an address bus of 24 bits, based on the fact that there's supposed to be a 32MB address space for it. I tried to trace the connections on my AR4M+ to determine the pinout, but it started getting a bit tricky and I decided to put it off. Tracing something really simple like an ST-Key (I assume ST-Key is nothing but a ROM and some passive components) or a standard AR would probably be much simpler.
