iMX7 Using UART on Cortex M4


I am trying to get the UART 3 running on the M4 Core.For that I use the uart_polling demo. I already added new cases for UART3 in the configure_uart_pins() / get_uart_clock_freq() and changed the defines of the UART2 to UART3. I read in some posts that after adding those cases everything works, atleast when Linux is not running.

I downloaded the project of Using uart3 on m4 - Technical Support - Toradex Community post and got the same results with the spamming UART

The UART reacts to my inputs, but it endlessly prints garbage onto the terminal. So it seems that there is a timing Problem, but I couln’t find it.

Is that a common error? Could the device tree cause the problem?(even when linux is not running?)
Do I have to change something in the UART_init?

Thanks in advance!

Greetings @Zimart!

Can you please share your changes to the device tree and a M4 example application where this occurs?

I’ve never seen such an issue so I’ll try to reproduce that on my side.

Sure sorry for the delay, unfortunately i cant upload the whole project, but here are all the files I modified:link text

In the main.c the defines are changed to UART3 defines.

In the board.h, defines are added for UART3 (Line 136-142)

In the clock_freq.c a case was added (Line 226-238)

In the pin_mux.c a case was added (Line 172-186)

Thanks in advance!


I’m going to give this a try and let you know my results.

Did you make sure to disable UART3 on the Linux side?

No I did not, but I thougth this should only be a problem when linux is running. But I will give it a try.
Thanks for your answere.