Tasmota/libesp32/NimBLE-Arduino

*** UPDATE ***

Server now handles long reads and writes, still work to do on client.

NEW Client callback created - bool onConnParamsUpdateRequest(NimBLEClient* pClient, const ble_gap_upd_params* params)
Called when the server wants to change the connection parameters, return true to accept them or false if not.
Check NimBLE_Client.ino example for a demonstration.

NimBLE-Arduino

A fork of the NimBLE stack restructured for compilation in the Ardruino IDE with a CPP library for use with ESP32.

Why? Because the Bluedroid library is too bulky.

Initial client code testing has resulted in code size reduction of ~115k and reduced ram consumption of ~37k.

Server code testing results from @beegee-toyo from the project here:

Memory usage (compilation output)

Arduino BLE library

RAM:   [==        ]  17.7% (used 58156 bytes from 327680 bytes)    
Flash: [========  ]  76.0% (used 1345630 bytes from 1769472 bytes)    

NimBLE-Arduino library

RAM:   [=         ]  14.5% (used 47476 bytes from 327680 bytes)    
Flash: [=======   ]  69.5% (used 911378 bytes from 1310720 bytes)    

Memory usage after setup() function

Arduino BLE library

Internal Total heap 259104, internal Free Heap 91660

NimBLE-Arduino library

Internal Total heap 290288, internal Free Heap 182344

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 v1.0.2 and 1.0.4 in Arduino IDE v1.8.12 and platform IO.

Usage:

This library is intended to be compatible with the original ESP32 BLE functions and types with minor changes.

Check 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 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 is 3.

Continuing development:

This Library is tracking the esp-nimble repo, nimble-1.2.0-idf master branch, currently @0a1604a.

Also tracking the NimBLE related changes in esp-idf, master branch, currently @48bd2d7.

Acknowledgments:

• @nkolban and @chegewara for the original esp32 BLE library this project was derived from.
• @beegee-tokyo for contributing your time to test/debug and contributing the beacon examples.

Todo:

1. Code cleanup.
2. Create documentation.
3. Expose more NimBLE features.
4. Add BLE Mesh code.