i finally got myself a working 65816 computer, though right now it's more of an experiment than an actual computer.

it's just a breakout board for the 65816 that plugs directly into my Altera DE2 FPGA Board. so i can do stuff with the 816 without designing a whole system from scratch.

currently the FPGA only acts as a clock source, ROM, and single IO Device (An 8 bit Register hooked up to the 8 green LEDs at the bottom right)
the test program just increments A, writes it to the IO Register, and then does an Increment Loop with Y (16-bit) to add a bit of delay so you can actually see the LEDs flashing.

it runs stable at 18.75MHz right now (pretty good for 3.3V! ), i also tried 25MHz and acording to the built-in Logic analyzer it was executing code normally, but it was unable to write to the IO Register or even capture the Bank Address reliably because the clock seemed totally out of phase with what the CPU was doing at the time.
so maybe the bank address/data bus multiplexer is a bit slow so it can lag behind the clock when it gets too fast?

either way i'll see if i can keep this speed as i add more things to the FPGA (i assume so since there is nothing between the CPU and FPGA being added, it's all internal so it should be a perfect target for overclocking)