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UART not working, signal very dirty

Posted: Sun Sep 24, 2017 10:24 am
by larroy
I couldn't get the UART to work, but I have a cp210x dongle which works with arduino very well. I connected TX to RX and RX to TX and GND.

I connected oscilloscope and saw the signal is very messy and going up to 6.2V what is going on?

https://1drv.ms/i/s!AmDLImexgdZ6oAQv0d-BkhHxODiu
https://1drv.ms/i/s!AmDLImexgdZ6oAWVGsKNyQgMXctt

Re: UART not working, signal very dirty

Posted: Sun Sep 24, 2017 10:39 am
by larroy
The diagram in this image is wrong, ground is the furthest form the board edge Please correct!!!!

http://wiki.friendlyarm.com/wiki/index. ... out-02.jpg

Re: UART not working, signal very dirty

Posted: Mon Sep 25, 2017 8:03 am
by Maroon5
larroy wrote:
The diagram in this image is wrong, ground is the furthest form the board edge Please correct!!!!

http://wiki.friendlyarm.com/wiki/index. ... out-02.jpg


The picture is correct,maybe you are using the V1.1 or V1.2 not V1.31

Re: UART not working, signal very dirty

Posted: Mon Sep 25, 2017 8:07 am
by Maroon5
larroy wrote:
I couldn't get the UART to work, but I have a cp210x dongle which works with arduino very well. I connected TX to RX and RX to TX and GND.

I connected oscilloscope and saw the signal is very messy and going up to 6.2V what is going on?

https://1drv.ms/i/s!AmDLImexgdZ6oAQv0d-BkhHxODiu
https://1drv.ms/i/s!AmDLImexgdZ6oAWVGsKNyQgMXctt

1.The reason for cp210x not working properly is the serial port is connected wrongly.
2.You had wired up wrong the GND
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