Jetson Nano Serial Port data reading problem

Good day to all.
I am using Jetson Nano developer kit in my project.
I need to control external device through uart, send command and read the data.

I am using onboard serial header, and cutecom (for testing purposes)
While I am sending data from Jetson Nano - it works good, external device receiving this data

But if I send data from external device to Jetson - serial port ( I am using ttyS0) stop working.
In cutecom I receive error message and port is closing

Did anybody met this problem?

What baud rate is the other end sending data at?

A low level on the UART input for too long may be interpreted as a “break” signal, which may generate a signal to the host program or an error to the TTY device driver.

You should hook up a logic analyzer or 'scope on the send/receive pins and see what’s going on when this problem happens.

Good day
Baud rate is 115200
We are using TX,RX and GND pin
The signal is not to long, no more than 11 bytes per second

I have connected Jetson Nano to the PC through the sparkfun connecter
Any data that I sent from Jetson to PC I can see in the serial port
But If I am trying to send any data to the Jetson (From the PC) - serial port on Jetson side stops to work.

After this - Jetson port start works as echo - if I send byte b1 to jetson - i am receiving the same byte back

Hi!
Is it well-known problem?

hello alexeypcmls4,

FYI,
here’s similar issue that sending data from PC to Nano has data loss occasionally, Topic 1063027.
we’re still have internal investigation about the failure.
thanks

hello alexeypcmls4,

FYI,
please have below two different approaches for your testing.

  1. we had verified that serial data is being transferred properly without any data loss with execute getty running at background,
    for example, on Jetson-Nano.
    $ sudo /sbin/getty -a ubuntu -L 115200 ttyTHS &

  2. Or, please stop stop the nvgetty service for verification.
    systemctl stop nvgetty systemctl disable nvgetty

same issue, but reverse.
my nano rx working but tx not.

Same issue. I followed the tutorials step by step. I have also disabled all "nvgetty` services and listed all processes using “/dev/ttyTHS1” on Jetson Nano. I am using Python-Serial package to echo back a packet. RX on jetson is working fine and receives the packet properly. But TX part not working (i.e. it sends back random bytes like FF FF 9F EF FE or 7E FF 7F FF BB). An suggestions?

it seems that nobody of nvidia can fix this problem.
@aghaee consider using CH340, that’s working perfectly. I have give up TX on jetson nano.

@ag3hbk Thanks for your advice. I think I have no other option but to use CH340 as you suggested. It was a headache for past days for me. Thanks.

Following.

Is this issue resolved? I am facing data packet loss issue on UART1_RXD pin 205. Somebody from NVIDIA please comment on the issue.

Hi

Please open a new topic for this issue. Thanks

Hi kayccc - have been seeing a similar problem…

Hello. Got same problem on SIM800L GPRS modem & on PL2303 USB-UART chips.
It is too low level on RXD pin, which leads to disconnect/error of PORT of Jetson Nano Tegra chip, not in kernel of Linux.
You need to check voltage level on RXD pin, it must be not lowel that 3V.

Is there a comprehensive solution for this, I have stopped and disabled nvgetty and the Jetson nano still cannot transfer data out but can read data, I am using Putty on windows as target manager and minicom on Jetson nano as device under test.

hello chinaedu.teteh,

may I know the pin connections you’d wiring to.
please also refer to Topic 81583, we had verified data transmit with serial port utility on Windows 7.
thanks

hi!
i have the same problem plz help me!

I got a similar problem communicating with a CNC Controller Board.
While everything works well on a Jetson Xavier NX I’m unable to re-create the setup and functionality on a Jetson Nano.

Full details here

Any suggestions are more then welcome.