Add README.

README.md

@@ -1,5 +1,43 @@
-# Hello World Example
+# DS18B20 1-Wire 
 
-Starts a FreeRTOS task to print "Hello World"
+## Introduction
+
+This is a ESP32-compatible C library for the Maxim Integrated DS18B20 Programmable Resolution 1-Wire Digital Thermometer device.
+
+It supports multiple devices on the same 1-Wire bus.
+
+## Supported Features
+
+ * External power supply mode (parasitic mode not yet supported).
+ * Static (stack-based) or dynamic (malloc-based) memory model.
+ * 1-Wire device detection and validation, including search for multiple devices on a single bus.
+ * 1-Wire bus operations including multi-byte read and write operations.
+ * CRC checks on ROM code and temperature data.
+ * Temperature convertion and retrieval.
+
+## Roadmap
+
+ * Simultaneous temperature conversion from multiple devices.
+ * Device configuration including resolution.
+ * Alarm support.
+ * Single device optimisations - avoid ROM addressing when only one device exists.
+ * Parasitic power support.
+ * EEPROM support.
+
+## License
+
+The code in this project is licensed under the MIT license - see LICENSE for details.
+
+## Links
+
+ * [DS18B20 Datasheet](http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf)
+ * [1-Wire Communication Through Software](https://www.maximintegrated.com/en/app-notes/index.mvp/id/126)
+ * [1-Wire Search Algorithm](https://www.maximintegrated.com/en/app-notes/index.mvp/id/187)
+ * [Espressif IoT Development Framework for ESP32](https://github.com/espressif/esp-idf)
+
+## Acknowledgements
+
+Parts of this code are based on references provided to the public domain by Maxim Integrated.
+
+"1-Wire" is a registered trademark of Maxim Integrated.
 
-See the README.md file in the upper level 'examples' directory for more information about examples.