Why TWAI (CANBUS) library not working for ESP32?

Question

I have created a simple circuit cor CANBUS (TWAI) communication between Arduino NANO and ESP32 Dev kit. At first I was using this library and my circuit works fine. this is te serial monitors:

But for ESP32 if I want to use TWAI library it is not responding and not working

this is TWAI codes:

#include 
#include 

// Define the TWAI GPIO pins for ESP32 Dev Kit
const gpio_num_t RX_PIN = GPIO_NUM_4;  // Change as needed
const gpio_num_t TX_PIN = GPIO_NUM_5;  // Change as needed

// Define the TWAI configuration
twai_general_config_t g_config = TWAI_GENERAL_CONFIG_DEFAULT(TX_PIN, RX_PIN, TWAI_MODE_NORMAL);
twai_timing_config_t t_config = TWAI_TIMING_CONFIG_500KBITS();
twai_filter_config_t f_config = TWAI_FILTER_CONFIG_ACCEPT_ALL();

void setup() {
  Serial.begin(115200);
  while (!Serial); // Wait for the serial port to connect
  delay(2000);

  Serial.println("Initializing TWAI (CAN) Receiver...");

  // Install TWAI driver
  if (twai_driver_install(&g_config, &t_config, &f_config) != ESP_OK) {
    Serial.println("Failed to install TWAI driver");
    return;
  }

  // Start the TWAI driver
  if (twai_start() != ESP_OK) {
    Serial.println("Failed to start TWAI driver");
    return;
  }

  Serial.println("TWAI (CAN) Receiver initialized");
}

void loop() {
  twai_message_t message;
  // Receive a TWAI message
  if (twai_receive(&message, pdMS_TO_TICKS(1000)) == ESP_OK) {
    Serial.print("Received a message with ID: 0x");
    Serial.print(message.identifier, HEX);

    if (message.rtr) {
      Serial.println(" [Remote Request Frame]");
    } else {
      Serial.print(" Data Length: ");
      Serial.println(message.data_length_code);
      for (int i = 0; i < message.data_length_code; i++) {
        Serial.print((char)message.data[i]);
      }
      Serial.println();
    }
  } else {
    // No message received within 1 second
    Serial.println("No message received");
  }
}

also in Arduino ide examples > esp > twai > twaireceive code is not working CODE:

/* ESP32 TWAI receive example.
  Receive messages and sends them over serial.

  Connect a CAN bus transceiver to the RX/TX pins.
  For example: SN65HVD230

  TWAI_MODE_LISTEN_ONLY is used so that the TWAI controller will not influence the bus.

  The API gives other possible speeds and alerts:
  https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/twai.html

  Example output from a can bus message:
  -> Message received
  -> Message is in Standard Format
  -> ID: 604
  -> Byte: 0 = 00, 1 = 0f, 2 = 13, 3 = 02, 4 = 00, 5 = 00, 6 = 08, 7 = 00

  Example output with alerts:
  -> Alert: A (Bit, Stuff, CRC, Form, ACK) error has occurred on the bus.
  -> Bus error count: 171
  -> Alert: The RX queue is full causing a received frame to be lost.
  -> RX buffered: 4  RX missed: 46 RX overrun 0

  created 05-11-2022 by Stephan Martin (designer2k2)
*/

#include "driver/twai.h"

// Pins used to connect to CAN bus transceiver:
#define RX_PIN 4
#define TX_PIN 5

// Intervall:
#define POLLING_RATE_MS 1000

static bool driver_installed = false;

void setup() {
  // Start Serial:
  Serial.begin(115200);

  // Initialize configuration structures using macro initializers
  twai_general_config_t g_config = TWAI_GENERAL_CONFIG_DEFAULT((gpio_num_t)TX_PIN, (gpio_num_t)RX_PIN, TWAI_MODE_LISTEN_ONLY);
  twai_timing_config_t t_config = TWAI_TIMING_CONFIG_500KBITS();  //Look in the api-reference for other speed sets.
  twai_filter_config_t f_config = TWAI_FILTER_CONFIG_ACCEPT_ALL();

  // Install TWAI driver
  if (twai_driver_install(&g_config, &t_config, &f_config) == ESP_OK) {
    Serial.println("Driver installed");
  } else {
    Serial.println("Failed to install driver");
    return;
  }

  // Start TWAI driver
  if (twai_start() == ESP_OK) {
    Serial.println("Driver started");
  } else {
    Serial.println("Failed to start driver");
    return;
  }

  // Reconfigure alerts to detect frame receive, Bus-Off error and RX queue full states
  uint32_t alerts_to_enable = TWAI_ALERT_RX_DATA | TWAI_ALERT_ERR_PASS | TWAI_ALERT_BUS_ERROR | TWAI_ALERT_RX_QUEUE_FULL;
  if (twai_reconfigure_alerts(alerts_to_enable, NULL) == ESP_OK) {
    Serial.println("CAN Alerts reconfigured");
  } else {
    Serial.println("Failed to reconfigure alerts");
    return;
  }

  // TWAI driver is now successfully installed and started
  driver_installed = true;
}

static void handle_rx_message(twai_message_t& message) {
  // Process received message
  if (message.extd) {
    Serial.println("Message is in Extended Format");
  } else {
    Serial.println("Message is in Standard Format");
  }
  Serial.printf("ID: %x
Byte:", message.identifier);
  if (!(message.rtr)) {
    for (int i = 0; i < message.data_length_code; i++) {
      Serial.printf(" %d = %02x,", i, message.data[i]);
    }
    Serial.println("");
  }
}

void loop() {
  if (!driver_installed) {
    // Driver not installed
    delay(1000);
    return;
  }
  // Check if alert happened
  uint32_t alerts_triggered;
  twai_read_alerts(&alerts_triggered, pdMS_TO_TICKS(POLLING_RATE_MS));
  twai_status_info_t twaistatus;
  twai_get_status_info(&twaistatus);

  // Handle alerts
  if (alerts_triggered & TWAI_ALERT_ERR_PASS) {
    Serial.println("Alert: TWAI controller has become error passive.");
  }
  if (alerts_triggered & TWAI_ALERT_BUS_ERROR) {
    Serial.println("Alert: A (Bit, Stuff, CRC, Form, ACK) error has occurred on the bus.");
    Serial.printf("Bus error count: %d
", twaistatus.bus_error_count);
  }
  if (alerts_triggered & TWAI_ALERT_RX_QUEUE_FULL) {
    Serial.println("Alert: The RX queue is full causing a received frame to be lost.");
    Serial.printf("RX buffered: %d	", twaistatus.msgs_to_rx);
    Serial.printf("RX missed: %d	", twaistatus.rx_missed_count);
    Serial.printf("RX overrun %d
", twaistatus.rx_overrun_count);
  }

  // Check if message is received
  if (alerts_triggered & TWAI_ALERT_RX_DATA) {
    // One or more messages received. Handle all.
    twai_message_t message;
    while (twai_receive(&message, 0) == ESP_OK) {
      handle_rx_message(message);
    }
  }
}

and RESULT:

12:21:11.915 -> Alert: A (Bit, Stuff, CRC, Form, ACK) error has occurred on the bus.
12:21:11.915 -> Bus error count: 118
12:21:12.909 -> Alert: A (Bit, Stuff, CRC, Form, ACK) error has occurred on the bus.
12:21:12.909 -> Bus error count: 119
12:21:12.909 -> Alert: A (Bit, Stuff, CRC, Form, ACK) error has occurred on the bus.
12:21:12.909 -> Bus error count: 120
12:21:13.901 -> Alert: A (Bit, Stuff, CRC, Form, ACK) error has occurred on the bus.
12:21:13.901 -> Bus error count: 121

I want to work with TWAI library. Because as a result I will use ESP32 s3 and this library can not support ESP32 S3.

Why TWAI (CANBUS) library not working for ESP32?

Answers (1)

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