Beaglebone ai64 usb serial debug output gibberish - on Ubuntu, ok on Windows

General Discussion
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Have had BeagleBone Blacks for years with no problems. Got new BeagleBone AI64. Due to problems getting some of the beagleboard published images to work on my ai64, I decided to use the USB-serial debug cable to capture boot information.

I have tried on Ubuntu 22 and Ubuntu 20 with failure. I’ve tried using the Ubuntu ‘screen’ app, minicom, and Putty to get output. All I got was gibberish.

So I switched to Windows 10 as my comptuer host and used same version of Putty (0.76) and same cables. Used Putty ‘serial’ emulator choice with 8N1 and flow ‘none’ and got correct output, getting all the way through login and doing things on the AI64 through the USB-serial cable (Adafruit one with AI64 adapter from digikey).

This post is to ask if anyone knows what settings on Ubuntu would make any of the clients listed above show readable output like Windows did? (I find it embarrassing that nothing worked on Ubuntu but it did on WIndows).

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Those are correct settings… Are you using a VM or native install of Linux… Sometimes, the usb-serial adapters can get out of sync with their data. Most of the time, just hitting reset on the board and starting fresh allows my serial devices to work again…

Regards,

3 Likes
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My favorite is

$ sudo apt install gtkterm

Also make sure you are in dialout group.

$ sudo usermod  -aG dialout  <username>
1 Like
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I’ll try gtkterm. Thanks.

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Thanks. I’ll try the reset.

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I got it to work by re-flashing the 2022-01-14 beagleboard-linked image.

What’s weird is that during this whole time, serial debug view continued to work on windows putty version while not working on Ubuntu (non-VM) Putty. Using same USB-to-serial-debug cables/adapters. Though Ubuntu was on different PC than Windows.

Whatever ‘broke’ it was probably due to the tinkering I was doing on the 2022-01-14 emmc firmware: updates, upgrades, some other techniques I found on internet to try to reset things. I kept trying because the debug worked on windows while this was going on.

Thanks for the help.

Now to explore other projects spawned by my quest for a fix: vm seamless host/guest file sharing, UEFI-signing of modules, building Beagle images from SDK’s, finding a fan-less case to deal with AI64 heat output. Much to learn.