Nope, not yet. My methodology is a little bit more "waterfall" as opposed to "agile." I could pull the trigger on the hardware now, but what if there's an issue with the hardware that presents itself during software development? It's not too expensive to respin the board but I find it better to sort of work toward the solution from all angles (hardware, Mac software, ESP32 software, mechanical, etc.) until completion of the minimum viable product is basically within striking distance in all areas. Only then am I gonna pull the trigger on the hardware and begin integration. I've made the mistake in the past of "finishing" the hardware too soon and then some other issue arises and I have to redo the hardware, spend more money, something along those lines, and oftentimes the project has ended up cancelled or abandoned.@Zane Kaminski Does it mean that you have the NuBus hardware working already ?
With this project in particular, the “all 74xx” approach is cute but the total chip count has grown to 40 chips. Maybe I should be using a CPLD or FPGA instead. It might be slightly more costly and proprietary but there would be far fewer total pins on the board. The decision is complicated by the uncertainty in when the chip shortage will end. As it stands, some ship dates are like 2 years out. With Xilinx Spartan-6 FPGA for example, I think the current estimated ship date is past the guaranteed EOL date. In nominal conditions it would be expected that Xilinx would commit to another 5 years or so of availability for Spartan-6 but many customers are afraid that Xilinx will ship a few final batches of S-6 and then discontinue it. Similarly on the small FPGA/CPLD side, Altera was about to unceremoniously discontinue the (3.3V) MAX II were it not for an outcry from their customers.
So does anyone have any thoughts as to whether I should keep going with the 74xx approach or switch to maybe a Lattice CPLD/FPGA? Bear in kind that 6-8 level shifting buffers will still be required even with the FPGA, but currently there are 37 74xx chips on the board. So an FPGA would bring a big reduction but the 74xx chips won’t be completely gone.
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