Friday, April 8, 2016

ATTiny Nano Programmer, Part 2

So layout went rather quickly on this one because it's pretty simple and I have too much fun doing this. Actually, the board is already on order with OSH Park.

I took some (read a lot of) design cues from Kevin Rye's ATTiny Programmer. Among other things, I liked the LED disable jumper, the IO breakout headers and the idea to create a programming board that one can also use in a project. I elaborated on the IO breakout by adding V+ and GND headers. Maybe it will be useful, maybe not. I also added a jumper to selected 3.3V or 5V and another to enable/disable the 10uF cap on the Nano's RST pin. There's also a dedicated RST switch for the ATTiny.

The overall profile mimics the Nano's with an extension opposite the USB connector on the Nano.

So here's the final design ...



And the schematic ...




Now I play the waiting game ... and discover where I screwed up. Which was ignoring a poorly placed via and at least one silkscreen mislabel. In the meantime, I've learned how to cover the vias with soldermask using Masks tab in the DRC. The final-er design is below.