Cann't tx/rx bytes by usart 3 on DART-MX8M board

user4users · ‎10-06-2020

Hello everyone.

I have DART-MX8M-MINI Evaluation Kit. And I want to send something via USART.

USART3 is free on this board.

I enabled USART3 in device tree. And when I am trying this cmd:

stty -F /dev/ttymxc2 -echo -onlcr 115200

I had got this:

[ 232.697916] imx-sdma 30bd0000.dma-controller: sdma firmware not ready!

[ 232.704455] imx-uart 30880000.serial: We cannot prepare for the RX slave dma!

[ 232.711815] imx-sdma 30bd0000.dma-controller: sdma firmware not ready!

[ 232.718351] imx-uart 30880000.serial: We cannot prepare for the TX slave dma!

I can’t transmit or receive bytes.

What I am doing wrong?

I tried to change status dma in device tree but this did not help me.

I am using Debian 10.6 and Linux imx8mm-var-dart 4.19.35.

Build image by this instructions:

igorpadykov · ‎10-06-2020

Hi user4users

for uart usage for that board may be useful to look at

In general this board was designed and supported by variscite, suggest to post issue on

Best regards
igor