I have a need for a digital I/O only solution, so I created one. I started with my first board (https://www.ghielectronics.com/community/creations/entry/16), took out the Cerb40 and moved the MCU and supporting hardware to the main board, along with some Darlington arrays for sink output and resistor arrays on the inputs. I believe the design is functional, at least on paper/CRT.
My first question is, what are my requirements as far as licensing? Since this is close to the Cerb40, which I used for “inspiration”, must I now open source the hardware? As for code, I’ve published most of it already in codeshare.
Second, I consider this to be more of a “daughter” board than as a main board. In the Gadgeteer realm, I envision it more as a smart module. I plan to create an adapter to allow gadgeteer connection via a U socket, while my primary target audience will use a Prolific USB to Serial cable for communication/control from a PC. Since my USB and my U socket are essentially the same (the USB solution additionally provides reset, loader, and battery lines), aside from 3.2mm mounting holes at 5cm, do I have to do more for Gadgeteer compatibility?
Third, and this is where I reach out to the hardware oriented side of the community, how do I debug this thing? My prototype boards came in (finally!) and I immediately started soldering components. After soldering the last one, I gave it one final once over, plug it in, and just as I expected, nothing happened. Ok, so maybe I expected perhaps a little bit of magic smoke, or [em]something[/em]. Now my lack of experience shines bright. I’m getting 5V in and 3V3 out at the voltage regulator. That’s about it. I don’t have precision probes for my meter, so I can’t really probe the MCU pins. I have boards and components for 9 more prototypes, so I have no problem doing it over. What are the “best practices” in putting together something like this?
Thanks all for reading, and thanks in advance for any help. Should I break this into three posts?