PIN  FUNCTION
===  ========

C15 TRACK Outputs On/Off Function via push button

A2  UART TX
A3  UART RX

A9  UART TX
A10 UART RX

A11 UART TX
A12 UART RX

A4  TRACK A H-Bridge Input
A5  TRACK A H-Bridge Input

A6  TRACK B H-Bridge Input
A7  TRACK B H-Bridge Input

B0  TRACK A H-Bridge Enable
B1  TRACK B H-Bridge Enable

B6  INA219 SCL
B7  INA219 SDA

C13 TRACK B Enable, pull low to disable 