DS18X20_ANY causes incorrect temperature in single sensor example code.

[AndyChessum]

The issue

Hi,

I tried both the multi and single example code in PlatformIO with a single DS18B20 sensor. The multi example worked fine, but the single example reported a temperature of 204 degrees. When I replaced DS18X20_ANY with the actual address of the sensor, the correct temperature was reported.

I have tried different sensors (always one at a time) and am using an external 4.7K resistor, as suggested.

Which SDK are you using?

esp-idf

Which version of SDK are you using?

master

Which build target have you used?

• [X] esp32
• [ ] esp32s2
• [ ] esp32s3
• [ ] esp32c2
• [ ] esp8266
• [ ] other

Component causing the issue

DS18x20

Anything in the logs that might be useful for us?

2mI (297) cpu_start: Starting scheduler on PRO CPU.␛[0m
␛[0;32mI (0) cpu_start: Starting scheduler on APP CPU.␛[0m
␛[0;32mI (1808) ds18x20_test: Sensor : 204.44°C␛[0m
Temperature 204.437500␛[0;32mI (3558) ds18x20_test: Sensor : 204.44°C␛[0m
Temperature 204.437500␛[0;32mI (5308) ds18x20_test: Sensor : 204.44°C␛[0m
Temperature 204.437500␛[0;32mI (7058) ds18x20_test: Sensor : 204.44°C␛[0m
Temperature 204.437500␛[0;32mI (8808) ds18x20_test: Sensor : 204.44°C␛[0m

Additional information or context

erbose mode can be enabled via -v, --verbose option CONFIGURATION: https://docs.platformio.org/page/boards/espressif32/nodemcu-32s.html PLATFORM: Espressif 32 (5.0.0) > NodeMCU-32S HARDWARE: ESP32 240MHz, 320KB RAM, 4MB Flash DEBUG: Current (cmsis-dap) External (cmsis-dap, esp-bridge, esp-prog, iot-bus-jtag, jlink, minimodule, olimex-arm-usb-ocd, olimex-arm-usb-ocd-h, olimex-arm-usb-tiny-h, olimex-jtag-tiny, tumpa) PACKAGES:

• framework-espidf @ 3.40401.0 (4.4.1)
• tool-cmake @ 3.16.4
• tool-esptoolpy @ 1.30300.0 (3.3.0)
• tool-ninja @ 1.9.0
• toolchain-esp32ulp @ 1.22851.191205 (2.28.51)
• toolchain-xtensa-esp32 @ 8.4.0+2021r2-patch3 Reading CMake configuration... LDF: Library Dependency Finder -> https://bit.ly/configure-pio-ldf LDF Modes: Finder ~ chain, Compatibility ~ soft Found 74 compatible libraries Scanning dependencies... Dependency Graph |-- ds18x20 | |-- onewire | | |-- esp_idf_lib_helpers | |-- esp_idf_lib_helpers Building in release mode Compiling .pio/build/nodemcu-32s/src/main.o Linking .pio/build/nodemcu-32s/firmware.elf Retrieving maximum program size .pio/build/nodemcu-32s/firmware.elf Checking size .pio/build/nodemcu-32s/firmware.elf Advanced Memory Usage is available via "PlatformIO Home > Project Inspect" RAM: [ ] 3.5% (used 11380 bytes from 327680 bytes) Flash: [== ] 17.0% (used 177781 bytes from 1048576 bytes) Building .pio/build/nodemcu-32s/firmware.bin esptool.py v3.3 Creating esp32 image... Merged 2 ELF sections Successfully created esp32 image.

Confirmation

• [X] This report is not a question nor a request for drivers.

[UncleRus]

I apologize for the delay in reply.

This happens because the function that calculates the measured temperature (esp_err_t ds18x20_read_temperature(gpio_num_t pin, ds18x20_addr_t addr, float *temperature)) cannot understand which family the sensor belongs to (because of DS18X20_ANY instead of address). In this case please use an explicit read/measure function, i.e. change the example, instead of:

res = ds18x20_measure_and_read(SENSOR_GPIO, SENSOR_ADDR, &temperature);

use

res = ds18b20_measure_and_read(SENSOR_GPIO, SENSOR_ADDR, &temperature);

I made changes to the driver and now in this case (impossibility to determine the sensor family) it will give an error.