lida2003 / BleSppUart

BleSppUart for SpeedyBee Test

BleSppUart

BleSppUart is try to support basic function (BetaFlight configurator) of SpeedyBee App.

Solution

Hardware

Supported Targets	ESP32	ESP32-C2	ESP32-C3	ESP32-H2	ESP32-S3
TBD	Tested	TBD	TBD	TBD	TBD

Software

ESP-IDF GATT SERVER SPP Example is based.

esp-idf-v5.0 \examples\bluetooth\bluedroid\ble\ ble_spp_server

How to Dev & Test

Step 1: create a working dir

$ mkdir test

$ cd test

Step 2: clone ESP IDF v5.0

$ git clone [e-mail]:espressif/esp-idf.git

$ cd esp-idf

$ git checkout release/v5.0

Step 3: setup dev environment

$ ./install.sh

Step 4: clone BleSppUart

$ cd ..

$ git clone [e-mail]:lida2003/BleSppUart.git

Step 5: enter dev environment

$ cd esp-idf

$ . ./export.sh

Step 6: build BleSppUart

$ cd BleSppUart

$ idf.py set-target ESP32

$ idf.py build

Note: try idf.py set-target target, if you have other module or dev boards.

Step 7: update firmware

$ idf.py -p /dev/ttyUSB0 flash monitor

Note: change ttyUSBx, x=serial port of the ttl module.

Summary

Current test result shows BLE-SPP UART is NOT supporting SpeedyBee.

So my premire rootcause is SpeedyBee has it's own protocol between mobile app and BLE SPP device through self defined truncate package format, detailed info see Connecting SpeedyBee or BetaFlightConfigurator with self make SPP device

Hope SpeedyBee can share more info.

Suspection

BLE SPP demo, default MTU size is 23

Wich suggests using multi packet transmission of communication frame. Since I didn't see any other value negotiated. So I think 23 is used for SpeedyBee.

Truncate package format

Full MTU package

'#' + '#' + total_num + current_num + rx_buffer[(spp_mtu_size-7)]

Last package

'#' + '#' + total_num + current_num + rx_buffer[(event.size - (current_num - 1)*(spp_mtu_size - 7))]

There are multi-times request for long packet response. it seems ok with UUI, API version and FC version msp commands. Not Compatible with SpeedyBee App #1