4 ms·
I suppose it depends on how you're using FPGAs. It seems like a lot of the FPGA products-- things like MISTer-- are system-level emulators, which rarely provid
by hakfoo 6y ago
I suppose it depends on how you're using FPGAs. It seems like a lot of the FPGA products-- things like MISTer-- are system-level emulators, which rarely provide full legacy I/O breakout. You can emulate a complete 68k Mac on a FPGA, but where do you attach that weird NuBus card?
Now, replacing individual chips with FPGAs/PLDs is likely to retain that, although I could imagine it's a lot less forgiving of an emulation, when it has to match the analog-domain properties of the original chip somewhat.
- monoideism 6y ago> You can emulate a complete 68k Mac on a FPGA, but where do you attach that weird NuBus card? I just looked, and NuBus has 96 pins with clock rate of like 20 MHz. There are FPGAs with > 500 GPIO that can easily handle that clock rate, and ones with over >200 GPIO that are fairly affordable. Now, I mess around with FPGAs, but I'm not an electrical engineer, and there may be other issues. But it seems doable. Any electrical engineer and/or hardcore FPGA hacker want to chime in?
- NovemberWhiskey 6y agoIt also looks like at least 30-40 of the pins on NuBus are either grounds or power supplies, so it's not even as bad it seems.
- monocasa 6y agoYeah, those wide parallel connections were pretty much universally power/ground heavy for signal integrity reasons.