I just tried loading Jambo Safari, but it crashes.
Need to find if any of the ROMs are working atm, so I can do some debugging stuff…

After cybdyn’s success with the DC, I realized that it should in theory be easier to make a ROM / GD emu for the NAOMI instead. Thought I might as well branch off in that direction while cybdyn is working on the DC side.

I’ve already traced some of the G1 bus stuff on the real NAOMI board.
Most of it goes to the Altera FLEX FPGA ofc, but it should be possible to bypass that chip altogether.

The G1 data bus passes through the bus tranceiver IC’s on the underside of the board, so that part is easy to solder to. I need to find the rest of the control signals, but shouldn’t be too hard.

I bought a NAOMI last year, but it had it’s HOLLY chip removed by the previous owner (I was aware of this, but it was only £20, so I grabbed it anyway). This is actually quite handy ofc, as it lets me trace the signals quite easily.

As you very likely know, the NAOMI accesses the ROM pack or DIMM board via some simple offset regs in the FPGA (via the G1 bus), so I think it should be doable to emulate this on another FPGA.

Even better is if DMA pausing works as expected, as we can then store “chunks” of data in a small-ish SRAM, and just stream new data from SD card / HDD.

I’m now in the process of sourcing a working NAOMI, but the MAME debugger will be a fantastic help in the mean time. I know a very minimum amount of coding under MESS / MAME though, so was wondering if you’d be interested in helping with the occasional question?

Please e-mail me if you get chance, be good to talk about this some more. 😉

Best regards,
OzOnE.