No Telemtry Data in APM Planner with UDP or Serial Connection

Navio / Edge Hardware
22

Thanks for the response!

I can change the radio settings and save them using APM Planner (I’m not sure how to do it with Qground control). Because of this I’m fairly confident the connection is good from my computer across the radio link. I’ll test uart to uart module connection with a multimeter. I’m also going to try to manually pass data across the serial connection…

23

Using my multimeter I verified that I have continuity from the solder points on the navio2 to the radio solder points for all the connected wires.

24

I was able to pass data over the serial radio connection manually from the Raspberry Pi to my GCS laptop.

On the Raspberry Pi I added this script:

import serial

ser = serial.Serial('/dev/ttyAMA0', 57600, timeout=.5)
 
while True:
    ser.write('Hello world!\r\n')

And ran it like this:

sudo python test-serial.py

On my Mac/GCS I opened screen like this:

screen /dev/cu.SLAB_USBtoUART 57600

And I received data!

I had to stop arducopter on the Raspberry Pi–because it accesses the '/dev/ttyAMA0 port on startup–in order to run my script so it seems like ardupilot is able to access the serial port. I rebooted the Raspberry Pi and connected again with screen from my Mac/GCS and I don’t get any data–it really feels like the Navio2 board is not sending any telemetry (or anything really) out the UART serial port… do I need to do anything to “turn on” UART data?

25

Success, finally!

So, I think, in the end, I had two issues.

  1. I was starting ardupilot with the -A flag set to tcp:0.0.0.0:5678:wait which caused ardupilot to wait indefinitely for a TCP connection (I had assumed it would wait for the TCP connection but also a serial connection–or at least finish startup–but this does not appear to be the case).
  2. Removing the A flag allowed ardupilot to complete startup but agetty was running on port ttyAMA0 so ardupilot could not connect to it. Once I killed the agetty process and restarted ardupilot I started to receive telemetry data on the UART connection.

Whew…

Is it worth updating the docs with a note about the agetty process preventing ardupilot from accessing ttyAMA0?

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