New ToyBrain Board Design
Version one of the ToyBrain boards had a bunch of problems:
- TX and RX were swapped on the serial line header
- The ICSP header was backwards
- There was no debug LED
- The SMD resistor pads for the reset pull-up resistor were too small
- The connection for the reset switch was a 0.1″ header rather than a proper footprint
- There was a lot of wasted space
Despite all of that, I managed to eventually get them working, with a slowed-down version of the Arduino bootloader, adapters for the ICSP and serial headers, and much messing about.
The new board is smaller, measuring about 1.5″ by 1.28″, and adds a proper reset switch, a SMD LED for debugging, corrected resistor footprints, and a (in my opinion) slicker layout. I still didn’t add voltage regulation or mounting holes, but I may be able to get a little space for the holes by moving a few traces in the corners of the board.