NuBusFPGA: HDMI on NuBus Macs

Melkhior

Tinkerer
Jan 9, 2022
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@alxlab Thanks; in fact I already have a printed 1.2mm version of your design waiting for measurement so I can add the appropriate holes for the connectors :)
 

techav

Tinkerer
Nov 30, 2021
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github.com
I'm glad to see someone making progress on this. It's something I've wanted to build for a while, but got stopped by the parts shortage. Even laid out some rough schematics based on the Graphics Gremlin, and also looked pretty deeply into using a Spartan 6. @Zane Kaminski and I exchanged notes a few times, but FPGAs are unobtanium. ICE40HX ship dates are a year out, and there aren't even estimates for Spartan 6 anymore.
 

Melkhior

Tinkerer
Jan 9, 2022
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@techav Short status, 'dumb' HDMI framebuffer is working fine with fixed-resolution and switchable bit depth (1/2/4/8/16/32 bits). Other features are still TODO.
It's a FPGA daughterboard on a carrier, so it's a bit bulky... Doing the board with the FPGA directly on it would require integrating all the support stuff for the Artix-7 (a Spartan-7 might suffice), which is beyond my schematics/PCB designing skill. If someone wanted to give it a go I'd be delighted :)
Spartan 6 are unlikely to come back, they are obsolete from Xilinx' point of view... 7-series are likely a better target for any 'new' design.

@alxlab Your excellent design of a bracket fits in the machine (Q650) just fine. Unfortunately, in the NuBusFPGA V1.0 the HDMI connector is low-riding on the PCB, and the cable-side connector (quite bulky on my cable) is too big to fit unless the board is slightly off-center from vertical... which using a bracket prevents, as it forces the board to be 'perfectly' aligned! So i have a bit of an issue there (or need a new HDMI cable...).