# No messages from PX4

Source: https://forum.modalai.com/topic/1586/no-messages-from-px4
Category: VOXL 2 and VOXL 2 Mini (https://forum.modalai.com/category/26/voxl-2-and-voxl-2-mini)
Tags: voxl-2
Posted: 2022-11-30 22:01:10 UTC by bendraper
Replies: 1 · Views: 644

## bendraper · 2022-11-30 22:01:10 UTC

Currently using a VOXL 2 connected to a CubeOrange flight controller over UART 1 (using M0125) and can't seem to successfully get a link. When I try to run the vision-px4 server, I get "WARNING: connected to voxl-mavlink-server but no messages from PX4." 

Running systemctl status voxl-vision-px4, I get the following

```
voxl2:/$ systemctl status voxl-vision-px4
● voxl-vision-px4.service - voxl-vision-px4
   Loaded: loaded (/usr/bin/voxl-vision-px4; enabled; vendor preset: enabled)
   Active: inactive (dead) since Wed 2022-11-30 21:04:56 UTC; 22min ago
 Main PID: 2284 (code=exited, status=0/SUCCESS)

Nov 30 21:04:56 m0054 voxl-vision-px4[2284]: exiting QGC udp listener thread
Nov 30 21:04:56 m0054 voxl-vision-px4[2284]: exiting localhost udp listener thread
Nov 30 21:04:56 m0054 voxl-vision-px4[2284]: udp_mavlink stopped
Nov 30 21:04:56 m0054 voxl-vision-px4[2284]: Stopping uart mavlink module
Nov 30 21:04:56 m0054 voxl-vision-px4[2284]: waiting for px4 mavlink timer thread to join
Nov 30 21:04:56 m0054 voxl-vision-px4[2284]: Stopping px4 monitor
Nov 30 21:04:56 m0054 voxl-vision-px4[2284]: closing remaining client pipes
Nov 30 21:04:56 m0054 voxl-vision-px4[2284]: closing remaining server pipes
Nov 30 21:04:56 m0054 voxl-vision-px4[2284]: Removing PID file
Nov 30 21:04:56 m0054 voxl-vision-px4[2284]: exiting
```

Also my mavlink server configuration is as follows

```
=================================================================
Parameters as loaded from config file:
px4_uart_bus:               1
px4_uart_baudrate:          921600
udp_port_to_px4:            14552
udp_port_from_px4:          14552
external_fc:                1
=================================================================
```

Any ideas?

## Reply by James Strawson (ModalAI staff) · 2022-11-30 23:40:59 UTC

Have you used an oscilloscope to probe the line from the flight controller to VOXL2 to make sure the flight controller is sending data at the correct baudrate? Also note that the logic level of that UART connector on M0125 is 3.3V, I'm not sure if that matches the expected logic level of the port you are using on the CubeOrange.

Also note PX4 requires some serial port configuration. We normally use mavlink channel 1 with the Telem2 port on our flight core set to 921600 and 'onboard' mode. This translates to the following px4 param settings, note that yours will most likely be different due to using a different flight controller in a different configuration.

MAV_1_CONFIG	102
MAV_1_FORWARD	0
MAV_1_MODE	2
MAV_1_RATE	0
SER_TEL2_BAUD	921600