HITL with voxl 2

[Tamas Pal 0]

@Matthew-Booker
In the VOXL2 PX4 HITL for software setup on voxl 2 the file voxl-px4-hitl file is missing in the voxl-master branch of github "https://github.com/modalai/px4-firmware/tree/voxl-master". We followed the instructions from "https://docs.modalai.com/voxl2-PX4-hitl/" I have tried this with both ubuntu and debian, results are still the same. Is it like that or there is some error? How to run hitl with voxl 2 as the files are missing.

[Zachary Lowell]

Hi @Tamas-Pal-0 - looks like you are correct in that the voxl-px4-hitl has not been pulled into voxl-master. I would recommend for now switching over to the voxl-dev branch and running with the steps through there. Once it has been pulled into voxl-master, then you can recompile, reflash, and run through it on that branch. Other options as well is you can copy the file voxl-px4-hitl from the voxl-dev branch into your current working voxl-master, recompile, and reflash the voxl2 with the newer firmware containing the correct executable.

[Tamas Pal 0]

Unable to run this command
echo 1 | sudo tee /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
In the terminal it is showing permission denied after running the command
tamas@tamas:~$ echo 1 | sudo tee /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
tee: /sys/bus/usb-serial/devices/ttyUSB0/latency_timer: Permission denied
1
How to fix the problem?

[Zachary Lowell]

@Tamas-Pal-0 said in HITL with voxl 2:

0

This seems like a permissions issue on your end and that your user doesnt have super user permissions.

[Tamas Pal 0]

@Zachary-Lowell

tamas@tamas:~$ echo 1 | sudo tee /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
tee: /sys/bus/usb-serial/devices/ttyUSB0/latency_timer: Permission denied
1
tamas@tamas:~$ ls /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
ls: cannot access '/sys/bus/usb-serial/devices/ttyUSB0/latency_timer': No such file or directory

How to fix it ?

[Eric Katzfey]

@Tamas-Pal-0 What do you get with ls /dev/ttyUSB*?

[Tamas Pal 0]

@Eric-Katzfey
I got this

tamas@tamas:~$ ls /dev/ttyUSB*
/dev/ttyUSB0

I am unable to modify anything inside /sys/bus/usb-serial/devices/ttyUSB0 with root user also. How to fix it?

[Eric Katzfey]

@Tamas-Pal-0 I'm not sure. This works in our development environment so something must be different in your environment. What version of Linux are you using? What cable are you using?

[Tamas Pal 0]

@Eric-Katzfey
The issue is fixed. It was a hardware issue. I changed the ftdi cable and the issue was solved. The previous FTDI cable was not allowing me to change anything in /sys/bus/usb-serial/devices/ttyUSB0 directory. The file latency_timer was also not there. However with the other cable, there is no such issue. Thank you for your valuable input.

[Tamas Pal 0]

For 3.3v J18 jst port which port of ftdi cable should be used, CTS# or RTS# ?

[Eric Katzfey]

@Tamas-Pal-0 For UART it is just GND, TX, and RX

[Tamas Pal 0]

@Eric-Katzfey you mean we only have to connect 3 pins in j18 port ?

[Eric Katzfey]

@Tamas-Pal-0 Yes, the fourth pin is power and we don't want that one.

[Tamas Pal 0]

Is there any way to verify that FTDI cable is connected properly with J18 port ?

[Eric Katzfey]

@Tamas-Pal-0 The easiest way would be to recompile the modalai_dsp PX4 driver to add more debug messages. But if you aren't comfortable with that then we'll need to come up with something else.

[Tamas Pal 0]

How to do that? Is there any other way to this ?

[Eric Katzfey]

@Tamas-Pal-0 The simulator will be sending heartbeat messages out over the serial cable. You can use the screen program to see if anything is coming from voxl 2 in the serial cable.

[Tamas Pal 0]

@Eric-Katzfey How to use screen program in this case ?

[Eric Katzfey]

@Tamas-Pal-0 screen is just a standard Linux program. There are many ways to check the output of the serial port. To start, you could always just do cat /dev/ttyUSB0 and see if anything is coming out. This post shows how to get a hex dump: https://superuser.com/questions/1402386/view-serial-device-output-in-console-in-hex

[Tamas Pal 0]

The problem is solved. The problem was with ftdi cable. Thank you for your valuable inputs