Orin Nano R36.4 uart0 issue

[fengyus]

i am using Orin Nano R36.4. i want to use Uart0(which is pin99 and pin101 of Orin Nano). after i add codes in the device tree, ttyS3 is mapped to uart0 according to the dmesg log. but ttyS3 doesn’t work. also no signals in oscilloscope. it seems i meet the similar issue with this topic: 在rel36.4中如何使能uart0作为rs232使用 - Jetson & Embedded Systems / Jetson Orin NX - NVIDIA Developer Forums

after i short the uart0_tx and uart0_rx, i use picocom to try ttyS3:

anyone can help me?

[KevinFFF]

Hi fengyus,

Are you using the devkit or custom board for Orin Nano?

Could you run the following command on your board and share extracted_proc.dts for further check?

$ sudo dtc -I fs -O dts -o extracted_proc.dts /proc/device-tree

Please also share the full dmesg as file here.

[fengyus]

i am using custom board. i note that in the devkit, the uart0 is connected to the wifi_bt module. does that mean somewhere in the wifi/bt’s driver codes affect the uart0? and it switch to ttyTHS3 now. i don’t know why. but ttyTHS3 still doesn’t work.
dmesg.log (57.7 KB)
extracted_proc.dts.log (347.6 KB)

[KevinFFF]

@fengyus

i note that in the devkit, the uart0 is connected to the wifi_bt module. does that mean somewhere in the wifi/bt’s driver codes affect the uart0?

No, it is not used by default. It just means that this interface is from M.2 Key E.

[    3.543695] 3110000.serial: ttyTHS3 at MMIO 0x3110000 (irq = 196, base_baud = 0) is a TEGRA_UART

It seems you want to use UART-B and it is enumerated as /dev/ttyTHS3.

I’ve checked your device tree, it seems you configured the wrong value for interrupts property of 3110000.serial.
Please modify the following line to check if it could help for current issue.

		serial@3110000 {
			resets = <0x03 0x65>;
-			interrupts = <0x00 0xc4 0x04>;
+			interrupts = <0x00 0x71 0x04>;
			clocks = <0x03 0x9c>;
			compatible = "nvidia,tegra194-hsuart";
			status = "okay";
			reg = <0x00 0x3110000 0x00 0x10000>;
			phandle = <0x3b4>;
			reset-names = "serial";
		};

[fengyus]

i have made the uart0 work well. thanks a lot.