I needed a board to test the new Device Bus/Watchdog so I stripped a XPortHub2 and added the logic that can be seen in the top right corner. It occupies almost 1/4 of the board so it does require some space. I need to work on that to find an optimal layout/solution.
I am considering adding this to XPortHub2, but I will need to re-route the entire board and move up to 4 layers for that. On this Test board above I can still get away with this being 2 layers so a test round cost me 15.- USD and components. I also decided on adding 2 more pins (Spare1 and Spare2) to RPI bus – just in case.
The one thing I don’t like is the size of the STM32G070KB – it is the large version of LQFP32 and the same size as a LQFP48. It occupy some space, but I think that will be ok as I reorganize the boards. Lets order the boards so we can move on into SW.