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

PA0  TRACK Outputs On/Off Function via push button

PA2  UART TX
PA3  UART RX

PA9  UART TX
PA10 UART RX

PA11 UART TX
PA12 UART RX

PA4  TRACK A H-Bridge Input
PA5  TRACK A H-Bridge Input

PA6  TRACK B H-Bridge Input
PA7  TRACK B H-Bridge Input

PB0  TRACK A H-Bridge Enable
PB1  TRACK B H-Bridge Enable

PB8  INA219 SCL
PB9  INA219 SDA

PB10 TRACK B Enable, pull low to disable 