I'm trying to drive a motor control over the Raspberry Pi's GPIO serial pins (GPIO 14 and 15)
I've disabled the serial console, however, during bootup of the Raspberry PI, it still sends data over the serial pins. This sends seemingly random commands to the motor controller. Which is of course potentially dangerous and not what I want to happen.
My system:
- Raspberry Pi 3 B+
- Serial connection with the motor controller over GPIO 14 (it's one way, so GPIO 15 is not connected)
- Ubuntu MATE 18.04.4 LTS
What I have already tried:
- Use raspi-config to disable serial console (3 Interface Options > P5 1-wire > no (login shell) > yes (serial port) => this did not seem to work at all.
- in /boot/firmware/nobtcmd.txt I have removed the "console" parameter => this correctly disabled the login shell
What is working:
- When the Pi is booted, I can connect to the motor driver and send it commands. This works correctly
What is not working:
- During boot I have to disconnect the serial connection to the motor driver, because data is transmitted over the connection
My question:
- How can I completely disable all data written to the serial interface during boot?
