This video is on getting NPK values using RaspberryPI PICO . RS485 -TTL device used here is Auto Direction enabled.You get Tx,Rx pins on board.
CRC calulator online :
https://crccalc.com/?method=CRC-16/MO...
code download:
https://99ba69f9-3a9c-49a1-8c2a-52df0...