I am using Arduino Due to send number to computer over RS485 and USB. Sending is not an issue with USB cable plugged in. When i unplugg the USB cable and use power supply 9.0V, rx,tx are not working. I am using Rx as pin 0 and Tx as pin 1. I tried almost everyting, using resistors, capacitors, disabling AutoReset but they did not work for me. I do not know why but the maybe the Arduino Due works different from other boards.
Anny Suggestion ?
Thank you Best Regards.