AGX-ORIN uart4 cannot work

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Orin
1

Hi nv team:
We designed a carrier board for Orin.uart4 cannot receive and send normally.We did the following.
1.The pinmux file was modified to configure the uart4 transceiver pins to UD3_TXD and UD3_RXD in execl

image
image1479×51 2.93 KB

pinmux file:
tegra234-mb1-bct-gpio-p3701-0000-a04.dtsi.txt (3.7 KB)
tegra234-mb1-bct-pinmux-p3701-0000-a04.dtsi.txt (64.6 KB)

2.We establish that in the dtb file, serial@3130000 is enabled.
The following is a fragment of the dts file:

	serial@3130000 {
		compatible = "nvidia,tegra194-hsuart";
		iommus = <0x03 0x04>;
		dma-coherent;
		reg = <0x00 0x3130000 0x00 0x10000>;
		reg-shift = <0x02>;
		interrupts = <0x00 0x73 0x04>;
		nvidia,memory-clients = <0x0e>;
		dmas = <0x05 0x13 0x05 0x13>;
		dma-names = "rx\0tx";
		clocks = <0x02 0x9e 0x02 0x66>;
		clock-names = "serial\0parent";
		resets = <0x02 0x67>;
		reset-names = "serial";
		status = "okay";
		phandle = <0x350>;
	};

After the above work, we use an oscilloscope to observe the uart_tx, and the result is that the waveform cannot be output normally.
I also looked at other blog posts and observed the following:
①

root@tct-desktop:/home/tct/Desktop# cat /sys/kernel/debug/gpio | grep PH
 gpio-391 (PH.00               )
 gpio-392 (PH.01               )
 gpio-393 (PH.02               )
 gpio-394 (PH.03               |camera-control-outpu) out lo 
 gpio-395 (PH.04               |fixed-regulators:reg) out lo 
 gpio-396 (PH.05               )
 gpio-397 (PH.06               |camera-control-outpu) out lo 
 gpio-398 (PH.07               )

②We checked dmesg and did not find any information related to ttyTHS

root@tct-desktop:/home/tct/Desktop# dmesg grep | ttyTHS
bash: ttyTHS: command not found
dmesg: bad usage
Try 'dmesg --help' for more information.

③

tct@tct-desktop:~/Desktop$ sudo busybox devmem 0x02434020
0x00000000
tct@tct-desktop:~/Desktop$ sudo busybox devmem 0x02434018
0x00000000
tct@tct-desktop:~/Desktop$ sudo busybox devmem 0x02434010
0x00000400
tct@tct-desktop:~/Desktop$ sudo busybox devmem 0x02434008
0x00000000

Is there a good solution？thank you!

3

Hi 2282753676,

What’s your Jetpack version in use?

It seems both of your UART4_TX and UART4_RX pins are used by others.

Please share the full device tree for further check.

4

Hi Kevin,
Thank you for your reply.
My version of jetpack is jetpack 5.1.And below is the complete dtb file,please help me check if there is any problem.thanks!
kernel.dts (525.8 KB)
tegra234-p3701-0004-p3737-0000.dtb.zip (70.8 KB)

5

These 2 pins have been used as following:
PH.03: reset pin for camera

#define CAM0_RST_L	TEGRA234_MAIN_GPIO(H, 3)

camera-control-output-low {
	gpio-hog;
	output-low;
	gpios = <CAM0_RST_L 0 CAM0_PWDN 0

PH.04: for PCIe regulator

p3737_vdd_3v3_pcie: regulator@105 {
	compatible = "regulator-fixed";
	reg = <105>;
	regulator-name = "vdd-3v3-pcie";
	regulator-min-microvolt = <3300000>;
	regulator-max-microvolt = <3300000>;
	vin-supply = <&p3737_vdd_3v3_sys>;
	gpio = <&tegra_main_gpio TEGRA234_MAIN_GPIO(H, 4) 0>;

Please find above lines in your source device tree and remove them if you don’t need them in your use case.

6

Hi Kevin,
Thanks for your help, the problem is solved.

8

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