A few hours ago, I had communication issue between my Raspberry Pi and Servo Control Board using URAT(Universal Asynchronous Receiver/Transmitter).
I confirmed many times that the wire connection was right, but it just did not work. After referencing many articles, I found out how to make it work perfectly.
For the latest Raspbian installed Raspberry Pi, there are 2 steps to go.
Enable Serial Port & Disable Serial Console
Use serial0 instead of ttyAMA0
As reference 1 mentioned, because of the Bluetooth conflict, you’d better use
import serial
ser = serial.Serial('/dev/serial0', 9600)instead of
ser = serial.Serial('/dev/ttyAMA0', 9600)Since we have known the reason for this issue, it may also be possible that you disable Bluetooth on your Raspberry Pi(Though I have not tried it yet)
References
- Change ttyAMA0 to Serial0: https://www.raspberrypi.org/forums/viewtopic.php?t=180951#p1151498