TWAI (CANBUS) Library Not Working on ESP32 - Tech Support Site

Simple Circuit for CANBUS (TWAI) Communication with Arduino NANO/ESP32 Dev Kit

To create a simple circuit for CANBUS (TWAI) communication using an Arduino NANO or ESP32 Dev Kit, follow these steps:

1. Connect the MCP2515 CAN controller to the Arduino/ESP32.
2. Connect the terminated CAN bus to the MCP2515.
3. Use the appropriate TWAI library for your device.

The Circuit and TWAI Library

The MCP_CAN_lib works perfectly for an Arduino NANO and other AVR-based boards.

However, when using the same library for an ESP32 Dev Kit, you might encounter issues. This is because the SPI pins used by the MCP_CAN_lib for AVR-based boards do not match the ESP32's.

To overcome this, use the library TWAI_Library, specifically designed for the ESP32. The circuit remains the same for both devices.

MCP2515 (CAN controller)
 -----------------------------
 CS: <----- SPI CS pin 
 MOSI: <----- SPI MOSI pin
 MISO: <----- SPI MISO pin
 SCK: <----- SPI SCK pin
 INT: <----- interrupt request pin
 

Setting Up the Arduino IDE

To set up your development environment, follow these steps:

1. Install the TWAI_Library in your Arduino IDE.
2. Select "ESP32 Dev Module" as your board in the Tools > Board menu.
3. Select the appropriate port in the Tools > Port menu.

The Issue

A user reported that their TWAI (CANBUS) library is not working on the ESP32 Dev Kit.

Troubleshooting

Begin by:

1. Double-checking your wiring.
2. Checking for any issues with the TWAI_Library installation.

#include <TWAI.h>

TWAI twai = TWAI(CS_PIN, MOSI_PIN, MISO_PIN, SCK_PIN, INT_PIN);

void setup() {
 Serial.begin(115200);

 if (!twai.begin()) {
 Serial.println("Failed to initialize TWAI!");
 while (1);
 }
}

void loop() {
 twai.setFilter(TWAI_FILTER_CAN_ID | TWAI_FILTER_MASK_CAN_ID, 0, 0, TWAI_FILTER_MODE_ACCEPT_ALL);
 twai.sendMsg(0x15, 0, "Hello World!");
}

• Use the MCP_CAN_lib link for an Arduino NANO/AVR-based boards.
• Use the TWAI_Library link for an ESP32 Dev Kit.
• If your circuit is set up correctly and the TWAI library is installed correctly, and your code still fails, seek further assistance on the Tech Support Site.

References

• TWAI_Library. (2021, June 12). TWAI Library for ESP32. Retrieved from https://github.com/kriswiner/TWAI_Library
• MCP_CAN_lib. (2021, June 12). MCP_CAN_lib. Retrieved from https://github.com/autowp/MCP_CAN_lib