CAN on ESP32 Example

This project demonstrates a very small CAN setup using the ESP32 TWAI peripheral. Two applications are provided:

• sender – reads 0 or 1 from the serial monitor and sends a CAN message containing this value.
• receiver – listens for the message and toggles an LED accordingly.

The LED should be connected to GPIO25 through a current limiting resistor (100–400 Ω). Connect the CAN transceivers to 3.3 V and GND and wire the signals as defined in menuconfig (defaults are TX=GPIO32 and RX=GPIO33).

Hardware setup

You will need two ESP32 boards and two CAN transceiver modules (for example SN65HVD230). Connect each ESP32 to its transceiver and join the CANL/CANH lines. The demo LED should be attached to GPIO25 through the resistor. If you prefer other pins for TX, RX or the LED you can change them under CAN Example Configuration in menuconfig.

Building and flashing

1. Clone the repository:

   git clone https://github.com/Geibinger/CAN_ESP32_Example

2. Open the project with the provided VS Code devcontainer. When prompted, choose Reopen in Container. If no prompt appears, press Ctrl+P and run > Dev Containers: Rebuild and Reopen in Container. After the container is built, all ESP‑IDF tools are available.

3. Configure the build target using menuconfig. Under CAN Example Configuration select sender or receiver. Here you can also change the TX, RX and LED pins if required.

   idf.py menuconfig

4. Connect the ESP32 and build/flash the selected application:

   idf.py build flash

5. Repeat step 3 and 4 for the second ESP32 with the opposite target.

Running the demo

Open a monitor for each board:

idf.py monitor -p <PORT>

Entering 0 or 1 in the sender's monitor transmits a CAN message. The receiver prints the received value and switches the LED on (1) or off (0).