Layout of the Motor Controller Board

       _______ switch ports	
      / 
     /  ,---------- power (12-24V)
   ----------
   ````oo''''   ,--- PORTC values
   |        |  /
1F [H      H] 1F
   |        | 
37 [H      H] 37
   |  .--.  |
3B [H |mc| H] 3B
   |  `--'  |
2F [H      H] 3D
   `--====--'   
        ^--------- serial port