Can't read from serial port on Sabre IMX7 dual

[alexanderlecces]

I have an RS-232 cable plugged into my IMX7 board. The RS-232 has data coming from an external source to the board. I know data is flowing because I can read this data on a windows computer as soon as I plug it in. 

I am trying to simply read this data on my IMX7 board (which has the default Linux OS on it) and print it to the command line screen. I have tried doing cat ttymxc4 but nothing happens. I have tried this for ttymxc0, ttymxc1, ..., ttymxc6 but nothing is being received. By default only ttymxc0, ttymxc4, and ttymxc5 were enabled. I had to edit the .dtb file to enable all seven serial ports (but I still do not get data from any of them). 

Is there something I am missing here? how do you "map" a ttymx device to that RS232 port on my board (labelled CAN19 or J19). 

Please help me read this data into the command line. Thanks.

[ankitr_patel]

Hi Alexander

DB-9 Connector (CAN19 or J19) on IMX7DSABRESD is Internally connected with MC33901WEF (High Speed CAN Transceiver). so it is Only used as CAN Interface Port. We can not use it is as Serial Connector.

You Can Find it from Quick Start Guide

Link:- https://www.nxp.com/docs/en/user-guide/SABRESDBIMX7DUALQSG.pdf 

If you Want to Receive Data serially you Have to Connect Micro-USB to Debug UART Port (J11) on the IMX7DSABRESD Board.

Best regards
Ankit
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[igorpadykov]

Hi Alexander

for uart test one can try unit tests, please check folder ..test/mxc_uart_test

available in i.MX 7Dual/Solo SABRESD Linux Binary Demo Files

https://www.nxp.com/webapp/Download?colCode=L4.1.15_2.0.0_iMX7D&appType=license&location=null&Parent... 

sources : imx-test
www.nxp.com/lgfiles/NMG/MAD/YOCTO/imx-test-5.7.tar.gz

Best regards
igor
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