First breakouts and adapter PCB ready!

A project log for Fabric8

Just in Time Logic

Nick JohnsonNick Johnson 05/14/2015 at 18:160 Comments

I've ordered and received the first prototype breakout boards for the Fabric8, and they work perfectly! I've also got an adapter PCB that allows for programming a Fabric8 from the official dev kit, which is perfect until we're done developing the Fabric8 dev kit.

You can see the design of the breakout boards here and the design of the adapter here. They're standard DIP 0.3" pitch and 0.1" spacing. VCC and GND pins match the standard used for 7400-series logic, with VCC in the top right and GND in the lower left. The bottom rows can be broken off to make ICs with fewer than 20 pins. Other than that I've tried to keep the native Greenpak pin numbering as much as possible I'll be shipping out breakouts and adapters to a few select Alpha testers soon.

Aside from being an opportunity to solicit feedback on the breakouts and development process, the adapter board serves as an opportunity to work on the design of the retaining clip for attaching the breakouts to the programmers. The goal is to be able to insert the breakout boards into the programmer without headers soldered on, using a row of spring pins to make contact with the pads. Once the device is programmed, it can be removed from the programmer and have headers - or wires - soldered in.

This requires a custom clip or socket of some sort. I'm not yet certain how it will look - some experimentation will be required. It's likely that it will be 3d printed or (eventually) injection moulded; I'm hoping for a single piece design for simplicity.