topic Re: IMX8M Mini working with UART3 in i.MX Processors

IMX8M Mini working with UART3

shai_b — Tue, 12 Apr 2022 09:19:35 GMT

Dear team,

My customer is trying to use UART3 with our IMX8MM-EVK, as I know such changes need to be done within the device tree.

but since the customer needs to change such a small parameter he would like to know if there is an option to change the UART3 of imx8mm (based on Yocto 5.15x Multimedia image) via U-Boot?

looking for your kind support, thanks in advance

KR,

Shai

Re: IMX8M Mini working with UART3

shai_b — Sat, 16 Apr 2022 23:45:05 GMT

There is any update?

KR,

Shai

Re: IMX8M Mini working with UART3

Rita_Wang — Tue, 19 Apr 2022 10:28:16 GMT

https://community.nxp.com/t5/i-MX-Community-Articles/How-to-Change-i-MX8MM-evk-Linux-Debug-UART/ba-p/1243938#M40 You can refer to this.

Re: IMX8M Mini working with UART3

shai_b — Sun, 17 Jul 2022 11:56:02 GMT

Hi @Rita_Wang ,

The customer does not want to change the debug port, but only to add the option to enable the UART3 so he can work use it on the user space?

can you please send me an example of how to change the correct device tree file and enable the UART3 to be 'active'?

Wating for your kind feedback, Many thanks.

Shai

Re: IMX8M Mini working with UART3

Rita_Wang — Tue, 19 Jul 2022 08:40:47 GMT

Like this, you can ask customer to try

imx8mn-evk.dtsi
1. Remove UART2

pinctrl_uart3: uart3grp {
   fsl,pins = <
   MX8MN_IOMUXC_UART3_RXD_UART3_DCE_RX 0x140
   MX8MN_IOMUXC_UART3_TXD_UART3_DCE_TX 0x140
   >;
};

/*
&uart2 {
   pinctrl-names = "default";
   pinctrl-0 = <&pinctrl_uart2>;
   status = "okay";
};
*/

&uart3 { /*Console*/
   pinctrl-names = "default";
   pinctrl-0 = <&pinctrl_uart3>;
   assigned-clocks = <&clk IMX8MN_CLK_UART3>;
   assigned-clock-parents = <&clk IMX8MN_SYS_PLL1_80M>;
   /*fsl,uart-has-rtscts;*/
   status = "okay";
};

2. changing uart2 to uart3
#include <dt-bindings/usb/pd.h>
#include "imx8mn.dtsi"

/ {
   chosen {
       stdout-path = &uart3;
   };