CAVeTalk

CAVEMAN controller message protocol

Protocol Structure

Version	ID	Length	Payload	CRC
1 Byte	1 Byte	1 Byte	0 - 255 Bytes	4 Bytes

1. Version refers to the communication version that packet adheres to, starting from V1 represented as 0x01
2. ID refers to the specific message being sent by the packet. Here is a list of the currently supported messages.

ID	Name	Descriptor
0x01	Ooga	CAVeTalk Ping Message, should receive "Booga" back from the controller
0x02	Movement	Describes the Speed [m/s] & Turn Rate of the Rover [rad/s]
0x03	Camera Movement	Describes the Camera Pan [radians] and Tilt Servo Angles [radians]
0x04	Lights	Toggles the Onboard Headlights
0x05	Arm	Enable or disable driving and steering
0x06	Odometry	Describes the 3 relative acceleration axes [m/s^2], 3 gyroscopic axes [rad/s], 4 unit quaternion positions and 4 encoder values for each wheel [rad/s]
0x07	Logging	Send String Messages Between Devices
0x08	Configuration - Servos - Wheels	Send Wheel Servo Configuration Parameters Between Devices
0x09	Configuration - Servos - Cams	Send Camera Servo Configuration Parameters Between Devices
0x0A	Configuration - Motors	Send Motor Configuration Parameters Between Devices
0x0B	Configuration - Encoders	Send Encoder Configuration Parameters Between Devices
0x0C	Configuration - Log	Send Log Verbosity Configuration Between Devices
0x0D	Configuration - Wheel Speed PID	Send PID Tuning Parameters for Rover Wheel Speed
0x0E	Configuration - Turn Rate PID	Send PID Tuning Parameters for Rover Turn Rate
0x0F	Air Quality Readings	Send Air Quality measurements like dust and gas content

3. Length refers to the length of the packet in bytes
4. Payload refers to the main piece of information sent in the packet

Protobufs

Protobufs are Google’s language-neutral, platform-neutral, extensible mechanism for serializing structured data. In this project, they are used to serialize message payloads.

C/Embedded

When building the C version of this library and/or using this library on an embedded system, follow these steps to setup Protobufs:

1. Initialize and update submodules

   git submodule update --init --recursive

   • Use this command to see the progress of each submodule pull

     git submodule update --init --recursive --progress

2. Make the script to generate the Protobuf payloads for C with nanopb executable.

   chmod +x tools/nanopb/generate.sh

3. Run the generate script to generate the Protobuf payloads for C with nanopb. This step requires Python3 to be installed.

   ./tools/nanopb/generate.sh

C++

When building the C++ version of this library, follow these steps to setup Protobufs:

1. Initialize and update submodules

   git submodule update --init --recursive

   • Use this command to see the progress of each submodule pull

     git submodule update --init --recursive --progress

2. Navigate to the protobuf directory

   cd external/protobuf

3. Configure CMake build

   cmake -S . -B _build -DCMAKE_INSTALL_PREFIX=_build/protobuf-install -DCMAKE_CXX_STANDARD=20 -G Ninja -DCMAKE_BUILD_TYPE=Release -Dprotobuf_BUILD_TESTS=OFF -DABSL_PROPAGATE_CXX_STD=ON

4. Build protobufs

   cmake --build _build --config Release

5. Install protobufs in external/protobufs/_build/protobuf-install

   cmake --build _build -t install

Build

Prerequisites

• CMake >= 3.30

• Ninja

• C compiler that supports at least C11

• C++ compiler that supports at least C++20

• Python3 >= 3.9 with python3-venv installed

• Gcovr (optional)

1. Setup Protobufs for the version(s) of the library being built. See Protobufs.

2. See the docs directory for how to perform static analysis and code formatting. You must set up Cppcheck and Uncrustify before configuring CMake.

3. Configure CMake.

   cmake -B build -G Ninja or cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug -DCAVETALK_BUILD_TESTS=ON to build with tests

4. Run the static analysis and code formatting tools.

   • Cppcheck: cmake --build build -t cppcheck
   • Uncrustify: cmake --build build -t uncrustify

5. Build the project.

   cmake --build build

6. If the project was configured to build tests, run the tests.

   cmake --build build -t test

7. If the project was configured to build tests and Gcovr is installed, generate a coverage report. The coverage report can be found in the build directory at coverage.html.

   cmake --build build -t coverage-no-test or cmake --build build -t coverage to run the tests and generate the coverage report in a single command