Just FYI after I’m done with this run there will be a small break. Don’t expect 3rd run to start right away, if at all. I want to focus a bit on other stuff, like PCE for example.
To that end I’ve already purchased DE1-SoC kit from Terasic/Altera. Original DE1 was quite popular due to both low price and pretty neat features like lots of I/O pins, SDRAM / SRAM / FLASH chips, VGA output and audio codec. People’ve managed to emulate Amiga 500 on that, as well as PC-XT class system (CPU and the peripherials) good enough to run Dune 2. But, DE1 was based on Cyclone II, something that Altera dropped support for about a year ago. So, basically GDEMU is based on (as of now) outdated FPGA.
DE1-SoC looks a lot like DE1 and also has a great price for what it is – the main reasons for the name not being DE6 I suppose. But the big difference is the “System on Chip” part, it’s not just a bigger and better FPGA from the current 28nm based Cyclone V family, it has two physical Cortex A9 cores integrated into it. Each core runs at 800MHz and is a bit more than twice faster compared to Raspberry Pi CPU overcloced to 900MHz. CPUs are connected to FPGA fabric with 2 high-speed busses and one slower, simpler 32-bit bus, which is easier to use in smaller projects. There are a few Linux based images provided with the board, and the SoC can boot either the CPU first from microSD memory card or the FPGA first from the on-board configuration chip.
I’ve already put this new toy to good use – its considerably bigger internal SRAM allows for bigger logic analyzer buffer. I could probably already make a prototype PCE drive replacement that would be good enough to run a few games. And that’s exactly what I want to try next.
Saturn project is also progressing nicely, I’ve built a prototype board to test a few ideas. The software side is not yet ready though – well, there’s no rush, but I would’ve tried something already if I wasn’t busy building GDEMU🙂