title_body: Serial Communication Not working in APM 2.8 I have being trying to establish Serial Communication connection between APM 2.8 and Raspberry Pi Board. But the connection is not being recognized in the Raspberry Terminal Console. 
  
  Configuration Setup:
  
  Model: Quad-copter
  
  Type: X
  
  Flight Controller: APM 2.8 FC
  
  Companion Computer: Raspberry Pi 3 Model B+
  
  I have being digging through web archives and found only MAVProxy Connection with Pixhawk &amp; Raspi. Any help, advice, or guidance would be helpful.  
  
  Current Refereed:Here
upvoted_answer: There are a bunch of problems which need to be overcome when using the RPi GPIO serial port.
  
  
  The RPi normally runs a login process on the serial port, this will need to be disabled.
  
  
  sudo systemctl stop serial-getty@ttyS0.service
  sudo systemctl disable serial-getty@ttyS0.service
  
  
  you will also need to edit /boot/cmdline.txt and remove this part: console=serial0,115200
  
  
  On a RPi 3/4 the port name in linux if different to the port name used on older RPi's.
  If using a recent image, the serial port is disabled in the config.txt by default. To fix this you need to edit /boot/config.txt and add the following line.
  
  
  enable_uart=1
  
  
  This page Configuring The GPIO Serial Port On Raspbian Jessie and Stretch Including Pi 3 and 4 has a very good writeup on how to get it all working.
  
  Also make sure that you are connecting RX on the RPi to TX on the APM and vice-versa.