New in Relay_V2 MCU:

PA0 - INPUT  - Water level (HIGH - we have water)
PA1 - INPUT  - E-STOP button (HIGH - normal state. should be interrupt-driven on falling edge detection)
PA2 \
PA3 ---------- Test points TP4, TP5 (ADC / USART1 / GPIO)
PA4 - OUTPUT - LED Lights TIM14 CH1 PWM output
PA5 - OUTPUT - RL_EN. Sets E-STOP trigger to controllable state (resets to normal state). LOW to activate. Should be HIGH by default.
PA8 - INPUT  - LED Lights switch
PB5 - OUTPUT - Second DC motor channel. TIM3 CH2 PWM
PB6 \
PB7 ---------- Test points TP1, TP2 (USART1, I2C1, GPIO)