DS18B20 OneWire Nano/Xavier

[phil]

I am trying to run the DS18B20 onewire thermal sensor from a Jetson Xavier. For testing purposes, i am using the jetson nano. We are using jetpack version 4.5.1 due to some other driver dependencies

I followed the following two forum posts:

Configuring DS18B20 temperature sensor using python on Jetson Nano

Hi, can someone help me configure DS18B20 temperature sensor using python on jetson nano? This is a one wire configurable type of sensor, can this be used to read data? When connected to the board on pin12 and ran simple_input.py, I could see the output “high”, but now I need to read data. How do I go about this?

Enable 1-wire on Jetson Xavier

I want to connect a DS18B20 sensor to a Nvidia Jetson Xavier and read its temperature. The resources below include direction for the following: jetson-gpio can configure the [GPIO pinout(NVIDIA Jetson Xavier NX GPIO Header Pinout - JetsonHacks) Kernal modification is required to enable CONFIG_W1_SLAVE_THERM and CONFIG_W1, then the driver will get enabled. Related Posts: Question What pin requires configuration so that the DS18B20 sensor can be read, and how can one do that with jet…

Based on this, i have made kernel modifications, recompiled and flashed the kernel and device tree.

For the kernel, i have added to the config file

CONFIG_W1_MASTER_GPIO=y
CONFIG_W1=y
CONFIG_W1_SLAVE_THERM=y

This can be checked in /sys/bus where is have aw1 directory

And for the device tree, i have added

onewire@0 {
compatible = “w1-gpio”;
gpios = <&gpio TEGRA_GPIO(H, 4) 0>;
};

This can be checked here: /proc/device-tree i can see: onewire@0

To check if things are working i have used the following python code in python 3.6

from digitemp.master import UART_Adapter
from digitemp.device import AddressableDevice
from digitemp.device import DS18B20

bus = UART_Adapter("/dev/ttyS0") #J44 header name

sensor = DS18B20(bus)

sensor.info()

print(sensor.get_temperature())

i get the following error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/nano/.local/lib/python3.6/site-packages/digitemp/device/thermometer.py", line 275, in __init__
    OneWireTemperatureSensor.__init__(self, bus, rom)
  File "/home/nano/.local/lib/python3.6/site-packages/digitemp/device/thermometer.py", line 32, in __init__
    self.rom_code = self.bus.read_ROM()
  File "/home/nano/.local/lib/python3.6/site-packages/digitemp/master.py", line 245, in read_ROM
    self.write_byte(0x33)
  File "/home/nano/.local/lib/python3.6/site-packages/digitemp/master.py", line 162, in write_byte
    raise AdapterError('Noise on the line detected')
digitemp.exceptions.AdapterError: Noise on the line detected

I am also not sure if my wiring is correct. I have a B01 carrier board on my jetson nano, and I am using both the Rx and Tx from the J50 header and the 3.3V /GND from the J41 header. RX and TX both go to the middle data pin and i have a 4.7k resistor going from the data pin to VCC

I am not sure if the device tree is correct for the jetson nano, but i am not sure what else to specify in the DTS: gpios = <&gpio TEGRA_GPIO(H, 4) 0>;

[ShaneCCC]

Have a reference to below link to figure the which GPIO pin.

NVIDIA Jetson AGX Xavier GPIO Header Pinout - JetsonHacks

[phil]

Thank you for your response.

As mentioned I am currently setting things up on the Jetson Nano. This is because i dont have regular access to a Xavier AGX, and I also cant easily reinstall the AGX.

I also checked the pinout of the nano, and I have problems on either UART pins. The J50 ones seem to be the right pins, because if I use the UART connectors on the J41 header, I receiver a Read/Write error. On the J50 pin, i get a ‘noise on the line’ error.

[ShaneCCC]

Below is the link for Nano

NVIDIA Jetson Nano J41 Header Pinout - JetsonHacks

[phil]

I am not sure what to do with this information, As mentioned, I already looked at this, and I tried both UART options on the Jetson Nano B01 board, neither of them working. (pins 8,10 on the J41 and pins 3 and 4 on the J50)

[ShaneCCC]

Did you configure the UART by jetson-io?

[phil]

jetson-io does not have an 1wire modification options for the DS18B20, at least not under jetpack 4.5.1, hence why i did the device tree modifications manually. The only options concerning UART are related to pins 11 and 36, which are not RX or TX.

[ShaneCCC]

Right, did you confirm the UART function after configure the PINs by jetson-io?
For the one wire need to have correct GPIO define for below.

gpios = <&gpio TEGRA_GPIO(H, 4) 0>;

[phil]

@phil

sensor = DS18B20(bus)

same error after enabeling the uartb-cts/rts in jetson-io.

As mentioned before, i modified, compiled and flashed the device tree, including the line gpios = <&gpio TEGRA_GPIO(H, 4) 0>; as this can not be done with jetson-io

[ShaneCCC]

Could you verify UART function only first.

[phil]

jetson-io does not offer any other options related to UART. Could you clarify what you mean with “verify UART function first”

[ShaneCCC]

Does your UART working? If didn’t please configure the PINS by jetson-io for it.

[phil]

i did enable the uart shown here, and rebooted afterwards. No difference unfortunatly

[ShaneCCC]

So UART didn’t work on Nano or Xavier?

[phil]

Nano, as mentioned above, i can only test this on the Nano on a B01 board. I dont have access to an agx right now.

[JerryChang]

please also access application note, Jetson Nano Developer Kit 40-Pin Expansion Header GPIO Usage Considerations Applications Note.

[phil]

This is quite time intensive to implement, so I ended up dropping the sensor. In hindsight, a simple solution is to use a raspberry pi pico, which already supports the DS18B20. This way, you can get the sensor working within a couple of hours and just need to make a serial interface between the agx and the pico. This is not an ideal solution as you now need extra space and power, but this should be manageable for most projects.