PCB: First Cut

A project log for Ugly FPGA Breakout

Ugly prototyping with diminutive FPGAs...why not?

ted-yapoTed Yapo 03/01/2018 at 03:090 Comments

So, I threw together a quick breakout PCB for the MachXO2-1200 FPGA. The idea is that you mount it to a solid ground plane (un-etched copper clad) by soldering down the castellations on the edges, then connect it up with wire wrap (twisted pairs when needed).

The bottom has no soldermask, so it can make good contact with the ground plane.  You could theoretically reflow it to the plane, but if you just tack-solder the 6 castellations, you could remove the PCB if desired.

The circuit is pretty simple: FPGA, bypass caps, and a 4k7 pulldown on the JTAG clock line I shamelessly stole from the TinyFPGA design.  It presumably keeps the clock from toggling spontaneously and screwing things up. It's mostly solder pads, really.  I added s 5-pin surface-mount header that's compatible with the TinyFPGA programmer.

I've sent design to OSH Park, and now just have to wait.

In case anyone is wondering what this is all about, here's another project I made with similar boards: