I need to communicate via the RPi3 serial port with a device that only understands hex commands. I have read and implemented the steps shown in: How do I make serial work on the Raspberry Pi3 and my device communicates, but with frequent bursts of high baud rate interference that shuts down my device. My /boot/config.txt includes: dtoverlay=pi3-disable-bt dtoverlay=pi3-disable-wifi core_freq=250 I am running Jessie with apt-get update and apt-get upgrade complete. Can you tell me what is interfering with my python script and how to stop it?
The system can use the serial link as a console to allow remote logins and may print system messages during boot.
Check that you have disabled these features (perhaps by using rsaspi-config).