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A Lisa Inside An FPGA

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ried:
That is astonishing. Congratulations, Alex! Looking forward to seeing it in the real world.

bmwcyclist:
I am stunned fantastic work thank you!!

AlexTheCat123:
Getting pretty close now!

The whole board is laid out and most stuff is routed too, with the exception of the traces to/from the FPGA itself. All the individual subsystems and power are completely hooked up though, and you might be able to see that a few things (the config flash, JTAG, differential pairs for USB and HDMI, and half the SRAM) are routed to the FPGA at this point. And all the pins on the BGA are fanned out (which was an absolute nightmare), so it's just a matter of connecting everything to them now. Although I'm anticipating that being a pretty big challenge given how dense everything is and the fact that I'm using literally every single I/O pin on the FPGA.

In case anyone's wondering, I decided on a 6-layer board with planes for 3.3V and ground, and the other 4 being signal layers. I didn't bother making power planes for 5V, 1V, 1.8V, or any of the other voltages because they're used so sparsely that it was just more efficient to route them on one of the internal signal layers.

Out of curiosity, I threw the design into JLCPCB to see how much it would cost, and fabricating 5 bare boards comes out to about $60. When you add their assembly service to that and ask them to assemble 2 of the 5 boards, the total price comes up to $438. About $200 of that is parts ($100 per board) and the rest is labor. So people probably won't want to order a set of boards unless they're buying several and selling the ones they don't use themselves. I checked the price for ordering and assembling 100 of them, and it comes out to about $8000, so you really do save a lot when you buy in bulk. That's only $80 per fully-assembled board!

I've attached a rendering of the PCB so you can get an idea of what it'll look like. The layout is completely finalized; the only thing that should change from here is the routing of traces going to/from the FPGA.

stepleton:
Impressive and certainly a project for the advanced home soldering enthusiast.
I can see the floppy emulator you've mentioned before. But I also notice the wall of capacitors to keep out the riff-raff ;-)
It's interesting to see all the DC-DC conversion on the board; I'm guessing that using off-the-shelf switching regulators is pricier?

I've never used an assembly service (but would have to in this case). Would there be some savings possible if you just used them for the surface-mount parts and left through-hole parts for the buyer to sort out?

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