nanopb-cobs-example

A simple example utility showing how to encode and decode nanopb protobufs with COBS framing. The framing is required to transmit variable length protobufs over stream interfaces without sidechannels (e.g. SPI).

Build

Note

Clone this repository with the --recursive flag to download the git submodules or run git pull --recurse-submodules.

Build using cmake and python. To include the python protobuf and grpcio tooling required for nanopb it is recommended to create a venv first:

python3 -m venv venv
source ./venv/bin/activate
pip install -r requirements.txt
cmake -Bbuild -GNinja && cmake --build build

Now find two executables in the build directory:

./build/nanopb-cobs-example_encode && ./build/nanopb-cobs-example_decode

Example output:

--- Encoder ---
Chose lucky number 28
Protobuf encoded message size: 2 bytes
08 1c
COBS encoded message size: 4 bytes
03 08 1c 00
Writing to file message.bin
--- Decoder ---
Encoded message from file size: 4 bytes
03 08 1c 00
COBS decoded message size: 2 bytes
08 1c
Your lucky number was 28!