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UART loop back process
#1
Hi, 

I am new to linux and Tinker board too. I need to test UART loopback process with GPIO pin 8 and 10. Please help me.
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#2
Just short the TX to RX, then in program like picocom or minicom then the character that you type will be echoed back.
Anything different I (we) don't get your meaning. Expand a little.
You might search on the forum with UART as keyword (top right hand corner)
Light blue words might be a link. Have you try to click on them? Big Grin
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#3
(01-31-2019, 11:37 PM)Im4Tinker Wrote: Just short the TX to RX, then in program like picocom or minicom then the character that you type will be echoed back.
Anything different I (we) don't get your meaning. Expand a little.
You might search on the forum with UART as keyword (top right hand corner)

Thanks for your reply.

I tried the same. but its not showing any thing on screen, even i am not able to exit from minicom as i open it.

i used command to open UART
1.           minicom -b 115200 -o -D /dev/tty0

2.           picocom -b 115200 /dev/tty0

              picocom v1.7

              port is        : /dev/tty0
              flowcontrol    : none
              baudrate is    : 115200
              parity is      : none
              databits are   : 8
              escape is      : C-a
              local echo is  : no
              noinit is      : no
              noreset is     : no
              nolock is      : no
              send_cmd is    : sz -vv
              receive_cmd is : rz -vv
              imap is        :
              omap is        :
              emap is        : crcrlf,delbs,

              Terminal ready



$ uname -srvo
Linux 4.4.103+ #1 SMP Fri Jun 22 16:14:49 CST 2018 GNU/Linux


and also want to know that is there any RS232 to TTL driver required to send and receive data from any computer or I may directly connect Rx Tx pins to my computers RS232 port's Tx Rx pins respectively.
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#4
The ttyS0 is not accessible by the hardware. You might find a result on ttyS1,ttyS3 or ttyS4. Then you can short the pins and you'll see the characters echoed back.
My video will show you how it works on ttyS1


BTW, to exit picocom, just use CTRL+A followed CTRL+X.

So later on, you may connect a serial communication to those pins, but remember that are at 3.3 Volt level. So if your intent is to monitor on the PC USB, you'll need a USB-RS232 adapter, see this.
Light blue words might be a link. Have you try to click on them? Big Grin
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