MavESP8266

ESP8266 WiFi Access Point and MavLink Bridge

This was developed using a NodeMCU v2 Dev Kit as it conveniently provides a secondary UART for debugging. It has been tested with the ESP-01 shipped with the PixRacer and it is stable at 921600 baud.

The build enviroment is based on PlatformIO. Follow the instructions found here: http://platformio.org/#!/get-started (only tested on Mac OS) for installing it but skip the platform init step as this has already been done, modified and it is included in this repository. In summary:

sudo pip install -U pip setuptools
sudo pip install -U platformio
git clone --recursive https://github.com/dogmaphobic/mavesp8266.git
cd mavesp8266
platformio run

When you run platformio run for the first time, it will download the toolchains and all necessary libraries automatically.

Useful commands:

• platformio run - process/build all targets
• platformio run -e esp12e - process/build just the ESP12e target (the NodeMcu v2)
• platformio run -e esp12e -t upload - build and upload firmware to embedded board
• platformio run -t clean - clean project (remove compiled files)

The resulting image(s) can be found in the directory .pioenvs created during the build process.

MavLink Submodule

The git clone --recursive above not only cloned the MavESP8266 repository but it also installed the dependent MavLink sub-module. To upated the module (when needed), use the command:

git submodule update

Wiring it up

User level (as well as wiring) instructions can be found here: https://pixhawk.org/peripherals/8266

• Resetting to Defaults: In case you change the parameters and get locked out of the module, all the parameters can be reset by bringing the GPIO02 pin low (Connect GPIO02 pin to GND pin).

MavLink Protocol

The MavESP8266 handles its own set of parameters and commands. Look at the PARAMETERS page for more information.

HTTP Protocol

There are some preliminary URLs that can be used for checking the WiFi Bridge status as well as updating firmware and changing parameters. You can find it here.

固件升级模式

整体流程：

--> TCP客户端（Qt端）连接至TCP Server（ESP8266）

--> TCP客户端（Qt端）向TCP Server发送执行流程（0x01+0x20:upload模式 ，0x02+0x20:erase模式）

--> TCP Server（ESP8266） 向飞控发送同步信号、擦除信号

--> (erase模式： TCP Server向飞控发送重启信号，并向TCP发送结束信号)

--> upload模式：

LOOP Begin： TCP Server（ESP8266）向TCP客户端（Qt端）发送数据请求

TCP Server（ESP8266）接收到一帧数据

TCP Server（ESP8266）按照Bootloader定义的数据格式发送至飞控     

LOOP End： TCP Server（ESP8266）检测到最后一帧数据并发送完成

--> TCP Server(ESP8266)向飞控发送重启信号，并向TCP客户端（Qt端）发送结束信号

通信信号定义：

• 1、TCP Server(ESP8266)与TCP客户端（Qt端）通信信号定义(C代表TCP客户端，S代表TCP服务器)

  Qt-->ESP8266:

  模式（流程）选择信号： 0x31+0x08（upload模式）
  　　　　　　　　　　　　0x31+0x09(erase模式)

  回复信号: 0x31+0x10 (OK:程序继续)
  　　　　　　　　　　　　　0x31+0x11(invalid：调回至固件升级模式开始) 　　　　　　　　　　　　　0x31+0x12(结束固件升级模式)

  数据发送信号: 0x01+length+Data(非结束帧)
  　　　　　　　　　　　　 0x02+length+Data(结束帧)

  ESP8266-->Qt:

  数据请求信号: 0x31+0x01

  擦除确认信号: 0x31+0x02

  提示信号: 0x31+0x03

  结束信号: 0x31+0x04

• 2、TCP Server（ESP8266）与飞控通信信号定义（S代表ESP8266，V代表飞控）

  ESP8266-->飞控

  同步信号： 0x21+0x20

  擦除信号： 0x23+0x20

  烧写信号： 0x27+length+Data+0x20

  重启信号： 0x30+0x20

  飞控-->ESP8266

  回复信号： 0x12+0x10(OK) 0x12+0x13(invalid)

注：1中的信号为自定义，2中的信号为Bootloader中定义的

烧写细节：

每次烧写252个字节，该字节长度需在0-255之间，且必须为4的倍数。