DS18B20 on BigTreeTech Pi

BTT_Pi_DS18B20.md

DS18B20 on BigTreeTech Pi v1.2

BTT Pi uses AllWinner H616 CPU, and on https://github.com/bigtreetech/CB1 system, w1-gpio kernel module does not work.

However, there is an excellent custom module https://github.com/pstolarz/w1-gpio-cl

The following steps were tested on CB1 v2.3.3.

Wiring

DS18B20 Pinout
BTT Pi GPIO

Connect sensor VCC pin to 3.3V, GND to GND (obviously), and signal pin to selected GPIO. I used PC7, since it corresponds to the default w1 pin location on the Raspberry Pi header.
Don't forget to add a pull-up resistor between 3.3V and the signal pin. A 4.7 kOhm resistor is the recommended value.

NEVER connect anything while the printer is powered on!

I did not try parasitic power mode, and I don't recommend it. Klipper will shut down on subsequent read errors, and it might ruin your prints randomly. I did not have any problems with the standard 3-wire connection yet.

Compilation on CB1 system

The easiest way is to compile it directly on the device. The official guide needed to be modified slightly.

1. sudo apt-get install build-essential bc bison flex libssl-dev
2. sudo apt-get install linux-headers-current-sun50iw9
3. git clone https://github.com/pstolarz/w1-gpio-cl.git
4. cd w1-gpio-cl
5. ln -s /lib/modules/`uname -r`/build/include/linux w1
6. make
7. sudo make install

DKMS

Optionally, you can install it using DKMS

sudo dkms add .
sudo dkms install w1-gpio-cl/1.2.2

where 1.2.1 is the latest w1-gpio-cl release version.

Installation

For details, read the original README.

Pin Selection

The w1-gpio-cl module does not accept pin names; instead, it needs pin index. To list all available pins, run

sudo cat /sys/kernel/debug/pinctrl/300b000.pinctrl/pinmux-pins

Find your preferred pin (note that some pins might not work). I used PC7

pin 71 (PC7): UNCLAIMED

Now you can configure module options

echo 'options w1-gpio-cl m1="gdt:71"' | sudo tee /etc/modprobe.d/w1-gpio-cl.conf

Test Config

Try loading the module manually

sudo modprobe w1-gpio-cl

Verify that the module is loaded

lsmod | grep w1

You should see something like

w1_therm               28672  0
w1_gpio_cl             16384  0

You can verify the output of the dmesg for errors.

Automatic Loading

To load the module during boot, run

echo 'w1-gpio-cl' | sudo tee /etc/modules-load.d/w1-gpio-cl.conf

Reboot and verify that the module is properly loaded and working.

Configuration

See https://www.klipper3d.org/Config_Reference.html#ds18b20-temperature-sensor

Find out connected sensor addresses

sudo ls /sys/bus/w1/devices/

You will see output like

28-011319f769fe  w1_bus_master1

With that address, add a Klipper config section like this

[temperature_sensor my_sensor]
sensor_type: DS18B20
serial_no: 28-011319f769fe
sensor_mcu: CB1

Note that sensor_mcu must be set to the host, which is CB1 by default.

After restarting Klipper, your new temperature sensor should appear in the Mainsail/Fluidd UI automatically.

BTT_Pi_GPIO.png

It does not seem like sw issue, so check the hw.

Just tried another single sensor. Same thing, not getting anything. Took that same sensor and hooked it up to a D1 Mini with ESP Home and I get an address from it and temp readings. Sensor is good. So its a SW issue.