RK3566 Uart3 Noise or Meaningless Data Issue

myarikkaya

Hi, We have ROC-RK3566-PC-V1.2
We want to use uart3.
For this reason I applied the following steps.


Step 1: I compiled your ubuntu 18.04 sdk and booted  on our device.
Step 2: I enabled uart3 in k356x_linux_release_v1.3.0b_20221213/kernel/arch/arm64/boot/dts/rockchip/rk3568-firefly-port.dtsi like following line

&uart3 {
        status = "okay";
        pinctrl-names = "default";
        pinctrl-0 = <&uart3m1_xfer>;
};
I set status set to "okay"
Step 4: Recompile and update image on device
Step 5: Setup the serial settings with stty with command on the following line
- stty -F /dev/ttyS3 ospeed 115200 ispeed 115200 cs8
- stty -F /dev/ttyS3 raw  


Now, I can see the /dev/ttyS3 serial point  but I have some problems to communication with ttyS3

I am constantly getting data that looks like meaningless or noise.

This dataset looking like that: b2 b2 f6 f6 90 b2 b2 f6 f6 90 b2 b2 f6 f6 90 b2 b2 f6 f6 90
and this data repeating always




On the ROC-RK3566-PC Specification pdf the uart3 sharing pin with AUDIOPWM
May be it is our problem.

How can I fix this problem ?
Is our method of the enabling UART3 correct ?

myarikkaya

I solve my problem.

The original dtsi file looking like this

1. &uart3 {
   
2.         status = "okay";
   
3.         pinctrl-names = "default";
   
4.         pinctrl-0 = <&uart3m1_xfer>;
   
5. };

Copy the code

I applied that

1. &uart3 {
   
2.         status = "okay";
   
3. };
   
4. (delete the pinctrl-0 and pinctrl-names)

Copy the code