VIM Pro - Very strange issue with usb-uart

Hello Terry,

I work for Libéo and we got hard time sending a string from the Vim Pro to an other computer. We did try the following :

On fresh install of Ubuntu (same with our custom nougat image) on VIM we did set our uart to 9600 N81 with :

stty -F /dev/ttyUSB0 9600 cs8 -cstopb -parenb

then send a string with :

echo -n -e ‘hello’ > /dev/ttyUSB0

If we do so on a computer or a raspberry pi 3, we receive hello correctly. But with the vim we just receive the first character correctly then we receive garbage characters. If we change the message sent, the first character received is always the same then rest of the string is not the same.

We did try many boards, on both Ubuntu and Android Nougat, and get that problem every time. The serial to uart is a ch341. Do you have an idea how we can fix this.

Hi @numbqq please follow up.

Hello @XtremXpert

What version of Ubuntu you used to test? I tested VIM1_Ubuntu-server-bionic_Linux-3.14_arm64_EMMC_V2018103 and VIM1_Ubuntu-server-bionic_Linux-4.9_arm64_EMMC_V20181030, and test with CH341, it works well, the data send is correct.

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Hi there, I’ve also been working with the Khadas Vim Pro with @XtremXpert and we’re still having the issue despite using the build that @numbqq recommended to use and reported as working accordingly.

I’ve flashed the exact same build of Ubuntu and the issue was happening just like it always did even on an unused board that we’ve just cleaned flashed and that was never used beforehand.

We’re having the issue both on Android and Linux (Kernel 4.9) and we’re kind of running out of options here.

Hello @zdesautels

The connection I test is : VIM1 <=> USB <=> CH341 <=> UART <=> UART <=> PL2302 <=> USB <=> X86 PC, on X86 PC, I use minicom to receive the data from VIM1. Are you sure with this connection you still can’t receive data correctly?