Problem getting connection through the USB-UART module.

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ggb
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Problem getting connection through the USB-UART module.

Unread post by ggb » Thu Jan 10, 2019 10:08 pm

I have been able to copy an OS to an SD card and boot from the HC2, but I have not been able to see any data coming through the USB to UART module.

I have connected up the module to the appropriate 4 pin connector. I have connected the other end to a USB to be PC running Linux. The Linux system recognises the device is connected as /dev/ttyUSB0, and a red led is lit up on the module itself (since there is very little documentation for the module, I cannot say whether the led should be red or some other colour, only that this is all that is showing). Looking online, I see that I should configure the UART as 115,200 baud, 8 bit, 1 stop bit, no parity, no flow control. I have connected to the device with mimicom (as suggested in the online documentation), and also cutecom (very similar to minicom but has a GUI). Although these both see the device is there, but they see no traffic at all coming from the device even though I have rebooted the HC2 several times (using Armbian and also using OpenVault - I was able to talk to the OpenVault through its web interface and through SSH so I know that was up and running).

At this time I believe I have done everything that is documented to do for the device, so I cannot say whether there is something else I should do that I am not aware of or if there is a fault with the USB to UART module, or a fault with the connector on the motherboard.

rgmhtt
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Re: Problem getting connection through the USB-UART module.

Unread post by rgmhtt » Thu Jan 10, 2019 10:46 pm

I use screen as in:

sudo screen /dev/ttyUSB0 115200

<ctl-A><Sht-H> gets you session logging.

On my HC1, I have tested that while running, to connect the USB/UART adapter, plug it into my system, start up screen and am into my serial console session. I DID add to my /boot/extlinux/extlinux.conf:

Code: Select all

sed -i "s|append|& cpuidle.off=1 \
console=tty1 console=ttySAC2,115200n8 \
rd.driver.pre=ledtrig-heartbeat,xhci-plat-hcd no_bL_switcher|" \
/mnt/__boot/extlinux/extlinux.conf
This I picked up from someone else that used this for Fedora:

https://blog.christophersmart.com/2018/ ... -nas-armv7

and

https://lists.fedoraproject.org/archive ... OEOMRHNFZ/

I don't know if this applies to your distro.

ggb
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Re: Problem getting connection through the USB-UART module.

Unread post by ggb » Fri Jan 11, 2019 6:16 am

OK, found out what I was doing wrong. Did not run the minicom or cutecom under sudo so it did not have permission to actually read from the device.

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odroid
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Re: Problem getting connection through the USB-UART module.

Unread post by odroid » Fri Jan 11, 2019 10:18 am

My Ubuntu 18.04 host PC can run minicom over USB-UART module without 'sudo'.

I think you might need to make a udev rule file in your Fedora system something like this.
https://askubuntu.com/questions/112568/ ... ce-ttyusb0

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rooted
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Re: Problem getting connection through the USB-UART module.

Unread post by rooted » Fri Jan 11, 2019 10:22 am

You do need a udev rule, my Linux Mint laptop needs sudo to run minicom also.

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Re: Problem getting connection through the USB-UART module.

Unread post by umiddelb » Fri Jan 11, 2019 2:23 pm

... or add the user to the group named 'dialout'.

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Re: Problem getting connection through the USB-UART module.

Unread post by rooted » Fri Jan 11, 2019 3:07 pm

umiddelb wrote:... or add the user to the group named 'dialout'.
Thanks Uli Image

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