Refer to this link for CAN network setup: Create Your Own CAN Network With MCP2515 Modules and Arduino
In this tutorial, the CAN network is established between two Arduinos. You can achieve the same setup between the Vaaman board and an Arduino, or between the Vaaman board and an ESP.
You need to bring up the CAN interface link. To bring up can0 with a bitrate of 500 kbps, run:
sudo ip link set can0 up type can bitrate 500000
After this, you can proceed to perform CAN communication.
@vatsal plz check
I am sending and receiving data through a USB CAN tool (external tool), but it is not working
Refer to this video: https://www.youtube.com/watch?v=spVgKZkNpT8 , it explains how communication occurs between two MCP2515 modules, where the CAN network is established between two ESP32 boards. In our case, we have the Vaaman board on one side, and you can connect any compatible device on the other side to establish communication.
Also, refer to this link for a better understanding:https://www.youtube.com/watch?v=ZH_CCs12ptg&t=3s
You can refer to this code for the ESP, as I have tested it and it works correctly,
// Simple sketch that querries OBD2 over CAN for coolant temperature
// Showcasing simple use of ESP32-TWAI-CAN library driver.
// Default for ESP32
#define CAN_TX 21
#define CAN_RX 20
CanFrame rxFrame;
void sendObdFrame(uint8_t obdId) {
CanFrame obdFrame = { 0 };
obdFrame.identifier = 0x7DF; // Default OBD2 address;
obdFrame.extd = 0;
obdFrame.data_length_code = 8;
obdFrame.data[0] = 2;
obdFrame.data[1] = 1;
obdFrame.data[2] = obdId;
obdFrame.data[3] = 0xAA; // Best to use 0xAA (0b10101010) instead of 0
obdFrame.data[4] = 0xAA; // CAN works better this way as it needs
obdFrame.data[5] = 0xAA; // to avoid bit-stuffing
obdFrame.data[6] = 0xAA;
obdFrame.data[7] = 0xAA;
// Accepts both pointers and references
ESP32Can.writeFrame(obdFrame); // timeout defaults to 1 ms
Serial.println("Sending frame");
}
void setup() {
// Setup serial for debbuging.
Serial.begin(115200);
// Set pins
ESP32Can.setPins(CAN_TX, CAN_RX);
// You can set custom size for the queues - those are default
ESP32Can.setRxQueueSize(5);
ESP32Can.setTxQueueSize(5);
// .setSpeed() and .begin() functions require to use TwaiSpeed enum,
// but you can easily convert it from numerical value using .convertSpeed()
ESP32Can.setSpeed(ESP32Can.convertSpeed(500));
// You can also just use .begin()..
if(ESP32Can.begin()) {
Serial.println("CAN bus started!");
} else {
Serial.println("CAN bus failed!");
}
// or override everything in one command;
// It is also safe to use .begin() without .end() as it calls it internally
if(ESP32Can.begin(ESP32Can.convertSpeed(500), CAN_TX, CAN_RX, 10, 10)) {
Serial.println("CAN bus started!");
} else {
Serial.println("CAN bus failed!");
}
}
void loop() {
static uint32_t lastStamp = 0;
uint32_t currentStamp = millis();
if(currentStamp - lastStamp > 1000) { // sends OBD2 request every second
lastStamp = currentStamp;
sendObdFrame(5); // For coolant temperature
}
// You can set custom timeout, default is 1000
if(ESP32Can.readFrame(rxFrame, 1000)) {
// Comment out if too many frames
Serial.printf("Received frame: %03X \r\n", rxFrame.identifier);
if(rxFrame.identifier == 0x7E8) { // Standard OBD2 frame responce ID
Serial.printf("Collant temp: %3d°C \r\n", rxFrame.data[3] - 40); // Convert to °C
}
}
}
Once the setup is properly completed, you can send the following command from the Vaaman board cansend can0 7E8#0341058700000000
To receive data from the ESP, run the following command on the Vaaman board to monitor incoming messages: candump can0