esp-nimble-cpp/docs/index.md

# Overview

This is a C++ BLE library for the ESP32 that uses the NimBLE host stack instead of bluedroid.  
The aim is to maintain, as much as reasonable, the original bluedroid C++ API while adding new features  
and making improvements in performance, resource use and stability.  

**Testing shows a nearly 50% reduction in flash use and approx. 100kB less ram consumed vs the original!**  
*Your results may vary*  
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### What is NimBLE?
NimBLE is a completely open source Bluetooth Low Energy stack produced by [Apache](https://github.com/apache/mynewt-nimble).  
It is more suited to resource constrained devices than bluedroid and has now been ported to the ESP32 by Espressif.  
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# Arduino Installation
Download as .zip and extract to Arduino/libraries folder, or in Arduino IDE from Sketch menu -> Include library -> Add .Zip library.

`#include "NimBLEDevice.h"` at the beginning of your sketch.

Tested and working with esp32-arduino Arduino IDE and platform IO.  
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# ESP-IDF Installation
### v4.0+
Download as .zip and extract or clone into the components folder in your esp-idf project.

Run menuconfig, go to `Component config->Bluetooth` enable Bluetooth and in `Bluetooth host` NimBLE.  
Configure settings in `NimBLE Options`.  
`#include "NimBLEDevice.h"` in main.cpp.  
Call `NimBLEDevice::init("");` in `app_main`.  
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### v3.2 & v3.3
The NimBLE component does not come with these versions of IDF.  
A backport that works in these versions has been created and is [available here](https://github.com/h2zero/esp-nimble-component).  
Download or clone that repo into your project/components folder and run menuconfig.
Configure settings in `main menu -> NimBLE Options`.  

`#include "NimBLEDevice.h"` in main.cpp.  
Call `NimBLEDevice::init("");` in `app_main`.  
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# Using
This library is intended to be compatible with the original ESP32 BLE functions and types with minor changes.  

If you have not used the original Bluedroid library please refer to the [New user guide](New_user_guide.md).

If you are familiar with the original library, see: [The migration guide](Migration_guide.md) for details.  

Also see [Improvements_and_updates](Improvements_and_updates.md) for information about non-breaking changes.  

### Arduino specific:
See the Refactored_original_examples in the examples folder for highlights of the differences with the original library.  

More advanced examples highlighting many available features are in examples/NimBLE_Server, NimBLE_Client.  
    
Beacon examples provided by [beegee-tokyo](https://github.com/beegee-tokyo) are in examples/BLE_Beacon_Scanner, BLE_EddystoneTLM_Beacon, BLE_EddystoneURL_Beacon.  

Change the settings in the nimconfig.h file to customize NimBLE to your project, such as increasing max connections (default == 3).  

**Note To increase max connections in Arduino it is also required to change the controller max connections defined in sdkconfig.h.**  

This is located in your Arduino/hardware/espressif/esp32/tools/sdk/include/config folder.

The values in `sdkconfig.h` you will need to change are:  
```
#define CONFIG_BTDM_CONTROLLER_BLE_MAX_CONN 3  
#define CONFIG_BTDM_CONTROLLER_BLE_MAX_CONN_EFF 3  
```
In `nimconfig.h` the value is:  
```
#define CONFIG_BT_NIMBLE_MAX_CONNECTIONS 3  
```
Espressif has stated the hard maximum connections is 9.  
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# Acknowledgments

* [nkolban](https://github.com/nkolban) and [chegewara](https://github.com/chegewara) for the [original esp32 BLE library](https://github.com/nkolban/esp32-snippets/tree/master/cpp_utils) this project was derived from.
* [beegee-tokyo](https://github.com/beegee-tokyo) for contributing your time to test/debug and contributing the beacon examples.
* [Jeroen88](https://github.com/Jeroen88) for the amazing help debugging and improving the client code.
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