2021-07-08 21:01:41 +08:00
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.. _ds18b20_sample:
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DS18B20 1-Wire Temperature Sensor
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#################################
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Overview
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********
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This sample shows how to use the Zephyr :ref:`sensor_api` API driver for the
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`Maxim DS18B20`_ temperature sensor.
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.. _Maxim DS18B20:
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2022-09-28 21:06:30 +08:00
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https://www.maximintegrated.com/en/products/sensors/DS18B20.html
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2021-07-08 21:01:41 +08:00
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The sample periodically reads temperature data from the
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first available DS18B20 device discovered in the system. The sample checks the
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sensor in polling mode (without interrupt trigger).
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Building and Running
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********************
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The devicetree must have an enabled node with ``compatible = "maxim,ds18b20";``.
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See below for examples and common configurations.
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If the sensor is not built into your board, start by wiring the sensor pins
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as shown in the Figure Hardware Configuration of the `DS18B20 datasheet`_ at
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page 10.
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.. _DS18B20 datasheet:
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https://datasheets.maximintegrated.com/en/ds/DS18B20.pdf
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Boards with a built-in DS18B20 or a board-specific overlay
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==========================================================
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Your board may have a DS18B20 node configured in its devicetree by default,
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or a board specific overlay file with an DS18B20 node is available.
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Make sure this node has ``status = "okay";``, then build and run with:
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.. zephyr-app-commands::
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:zephyr-app: samples/sensor/ds18b20
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:goals: build flash
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:board: nucleo_g0b1re
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DS18B20 via Arduino Serial pins
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===============================
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Make sure that you have an external circuit to provide an open-drain interface
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for the 1-Wire bus.
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Once you have wired the sensor and the serial peripheral on the Arduino header
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to the 1-Wire bus, build and flash with:
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.. zephyr-app-commands::
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:zephyr-app: samples/sensor/ds18b20
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:goals: build flash
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:gen-args: -DDTC_OVERLAY_FILE=arduino_serial.overlay
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The devicetree overlay :zephyr_file:`samples/sensor/ds18b20/arduino_serial.overlay`
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should work on any board with a properly configured Arduino pin-compatible Serial
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peripheral.
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Sample Output
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=============
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The sample prints output to the serial console. DS18B20 device driver messages
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are also logged. Refer to your board's documentation for information on
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connecting to its serial console.
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Here is example output for the default application settings, assuming that only
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one DS18B20 sensor is connected to the standard Arduino Serial pins:
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.. code-block:: none
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*** Booting Zephyr OS build zephyr-v2.6.0-1929-gf7abe4a6689e ***
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Found device "DS18B20", getting sensor data
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[00:00:00.000,039] <dbg> w1_serial: w1_serial_init: w1-serial initialized, with 1 devices
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[00:00:00.015,140] <dbg> DS18B20: ds18b20_init: Using external power supply: 1
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[00:00:00.021,213] <dbg> DS18B20: ds18b20_init: Init DS18B20: ROM=28b1bb3f070000b9
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Temp: 25.040000
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Temp: 25.030000
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