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61 lines
2.7 KiB
61 lines
2.7 KiB
2 years ago
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# esp32-owb
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This is a ESP32-compatible C component for the Maxim Integrated "1-Wire" protocol.
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It is written and tested for version 3.0-3.3 and 4.1-beta1 of the [ESP-IDF](https://github.com/espressif/esp-idf)
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environment, using the xtensa-esp32-elf toolchain (gcc version 5.2.0, crosstool-ng-1.22.0-80-g6c4433a).
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Support for v2.1 is available on the [ESP-IDF_v2.1](https://github.com/DavidAntliff/esp32-owb/tree/ESP-IDF_v2.1) branch.
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## Features
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This library includes:
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* External power supply mode.
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* Parasitic power mode.
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* Static (stack-based) or dynamic (malloc-based) memory model.
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* No globals - support any number of 1-Wire buses simultaneously.
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* 1-Wire device detection and validation, including search for multiple devices on a single bus.
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* Addressing optimisation for a single (solo) device on a bus.
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* 1-Wire bus operations including multi-byte read and write operations.
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* CRC checks on ROM code.
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This component includes two methods of bus access - delay-driven GPIO and RMT-driven slots.
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The original implementation used CPU delays to construct the 1-Wire read/write timeslots
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however this proved to be too unreliable. A second method, using the ESP32's RMT peripheral,
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results in very accurate read/write timeslots and more reliable operation.
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Therefore I highly recommend that you use the RMT driver. *The GPIO driver is deprecated and will be removed.*
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See documentation for [esp32-ds18b20](https://www.github.com/DavidAntliff/esp32-ds18b20-example#parasitic-power-mode)
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for further information about parasitic power mode, including strong pull-up configuration.
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## Documentation
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Automatically generated API documentation (doxygen) is available [here](https://davidantliff.github.io/esp32-owb/index.html).
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## Source Code
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The source is available from [GitHub](https://www.github.com/DavidAntliff/esp32-owb).
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## License
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The code in this project is licensed under the MIT license - see LICENSE for details.
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## Links
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* [esp32-ds18b20](https://github.com/DavidAntliff/esp32-ds18b20) - ESP32-compatible DS18B20 Digital Thermometer
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component for ESP32
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* [1-Wire Communication Through Software](https://www.maximintegrated.com/en/app-notes/index.mvp/id/126)
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* [1-Wire Search Algorithm](https://www.maximintegrated.com/en/app-notes/index.mvp/id/187)
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* [Espressif IoT Development Framework for ESP32](https://github.com/espressif/esp-idf)
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## Acknowledgements
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Thank you to [Chris Morgan](https://github.com/chmorgan) for his contribution of adding RMT peripheral support for more
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reliable operation.
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Parts of this code are based on references provided to the public domain by Maxim Integrated.
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"1-Wire" is a registered trademark of Maxim Integrated.
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