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IWR6843AOPEVM: Intermittent Data Transmission

joelsa
Prodigy 30 points
Part Number: IWR6843AOPEVM

Tool/software: TICloudAgent, TICloudAgentBridge, mmWave Demo Visualizer (v3.5.0)

Hi, I have the following problems with my mmWave eval board:

Issue Description:

I'm experiencing intermittent data transmission with my IWR6843AOPEVM Rev. G radar sensor. The device is:
- Running the pre-built OOB binary for SDK 3.5
- Connected to the mmWave Demo Visualizer (v3.5.0)
- Using Google Chrome with TICloudAgentBridge Extension and latest TICloudAgent
- Configured with all SOP switches in OFF position for USB communication

The sensor consistently stops transmitting data after a brief period (1-15 seconds, typically 8-9 seconds).

Troubleshooting Steps Attempted:

I can temporarily restore functionality by:
1. Power cycling the device and reloading the configuration
2. Partially disconnecting only the USB D+/D- pins (leaving VUSB and GND connected), then reconnecting
- When doing this, the USB_LED LD4 (located next to the 40 MHz crystal) turns off
- When fully reconnected, the device resumes data transmission without reloading the configuration

In both cases, the eval board will stop transmitting after the same time periods as described above.

Additional Information:

- The device has already worked flawlessly
- Has been unused for about a month, now has the aforementioned problems
- The issue persists across multiple reboots, computers, and operating systems

Can you help identify the cause of this intermittent data transmission and suggest a permanent solution?

  • 0
    TI__Mastermind 19600 points

    Hello.

    Have you tried using a different cable to see if the issue still exists?  Have you also made any changes to configuration frame time?  It could be that the processing time is longer than the frame time allotted and that could cause issues as well.

    Sincerely,

    Santosh

  • 0 in reply to Santosh Krishnan
    Prodigy 30 points

    Hello Santosh,

    thank you for your answer.

    Yes, I have already tried multiple USB cables, including brand new ones. I have not made any changes to the config frame time, and use the default values from the OOB demo. CPU active and interframe load is also well below 20% all the time.

    Best regards,

    Joel

  • 0 in reply to joelsa
    TI__Mastermind 19600 points

    Understood.

    Have you tried a different device?  You mentioned you are using the same device after a long time, is this issue replicable on a different device?

    Sincerely,

    Santosh

  • 0 in reply to Santosh Krishnan
    Prodigy 30 points

    Yes, I just tried a brand new eval board and the issue is the same.

    However, while debugging the issue I found out the following:
    - The behaviour on Windows was different from the behaviour on Linux and most likely an unrelated issue
      - On Windows, the connection would drop altogether, on Linux the USB connection remains established but no data is coming in
      - I fixed the likely unrelated issue on Windows by installing new cp210x drivers, now the demo is running continuously on Windows
      - The behaviour on Linux (Ubuntu 24.04) is still the same

    A few days ago, before trying to get data out of the radar again using the mmWave Demo, I had to install a new TiCloudAgent version due to the installed version being out of date and now have BuildID: 0.5 5063 installed, whereas previously, the last time it worked, I had BuildID: 0.5 4921 installed.


  • 0 in reply to joelsa
    TI__Mastermind 19600 points

    Understood.

    This may be an issue with the linux version of the visualizer; if you are having issues with only the linux version of the demo visualizer, I would recommend you switch to the Industrial Visualizer in the radar toolbox instead; it provides a 3D visualization of the pointcloud as well and is python based.  You will have to run it from source but the source code is also provided in the toolbox.

    Sincerely,

    Santosh

  • +1 in reply to Santosh Krishnan
    Prodigy 30 points

    Hi, I traced the issue down. The pwrstatd is responsible. The pwrstatd defaults to enumerate all acceptable device nodes and pick up to use an available device node automatically. I added this line to /etc/pwrstatd.conf:
    `allowed-device-nodes = /dev/ttyS1;/dev/ttyS2;/dev/hiddev1`
    in order to disallow access to /dev/ttyUSB0 and /dev/ttyUSB1. This solves the problem.

    I hope this information is useful for anybody having the same issues.