ESP32 Forum

Code: Select all

static const can_timing_config_t t_config = CAN_TIMING_CONFIG_25KBITS();
//Filter all other IDs except MSG_ID
static const can_filter_config_t f_config = {.acceptance_code = (uint32_t)(MSG_ID << 21),
                                             .acceptance_mask = (uint32_t)~(CAN_STD_ID_MASK << 21),
                                             .single_filter = true};
//Set to NO_ACK mode due to self testing with single module
static const can_general_config_t g_config = {.mode = CAN_MODE_NO_ACK,
                                              .tx_io = (gpio_num_t)TX_GPIO_NUM,
                                              .rx_io = (gpio_num_t)RX_GPIO_NUM,
                                              .clkout_io = (gpio_num_t)CAN_IO_UNUSED,
                                              .bus_off_io = (gpio_num_t)CAN_IO_UNUSED,
                                              .tx_queue_len = 5,
                                              .rx_queue_len = 5,
                                              .alerts_enabled = CAN_ALERT_NONE,
                                              .clkout_divider = 0
                                              };

static SemaphoreHandle_t tx_sem;
static SemaphoreHandle_t rx_sem;
static SemaphoreHandle_t ctrl_sem;
static SemaphoreHandle_t done_sem;

/* --------------------------- Tasks and Functions -------------------------- */

static void can_transmit_task(void *arg)
{
    can_message_t tx_msg = {.flags = CAN_MSG_FLAG_SELF, .identifier = MSG_ID, .data_length_code = 1};

Code: Select all

#include <driver/can.h>
#include driver/gpio.h>
#include <esp_system.h>
#include <stdio.h>
#include <stdlib.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "freertos/semphr.h"


// define your CAN messages here, OR you can define them locally...
// standard 11-bit frame ID = 0
// extended 29-bit frame ID = 1
// format:   can_message_t (name of your message) = {std/ext frame, message ID, message DLC, {data bytes here}};

can_message_t myMessageToSend = {0, 0x123, 8, {0x01, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF, 0x99}};

uint32_t previousMillis;
const uint32_t interval = 1000;

//=================================================

void setup()
{
// anything else you might need to do....
setup_can_driver();
}

void setup_can_driver()
{
 can_general_config_t general_config = {
        .mode = CAN_MODE_NORMAL,
        .tx_io = (gpio_num_t)GPIO_NUM_5,
        .rx_io = (gpio_num_t)GPIO_NUM_4,
        .clkout_io = (gpio_num_t)CAN_IO_UNUSED,
        .bus_off_io = (gpio_num_t)CAN_IO_UNUSED,
        .tx_queue_len = 100,
        .rx_queue_len = 65,
        .alerts_enabled = CAN_ALERT_NONE,
        .clkout_divider = 0};
    can_timing_config_t timing_config = CAN_TIMING_CONFIG_500KBITS();
    can_filter_config_t filter_config = CAN_FILTER_CONFIG_ACCEPT_ALL();
    esp_err_t error;

    error = can_driver_install(&general_config, &timing_config, &filter_config);
    if (error == ESP_OK)
    {
        Serial.println("CAN Driver installation success...");
    }
    else
    {
        Serial.println("CAN Driver installation fail...");
        return;
    }

    // start CAN driver
    error = can_start();
    if (error == ESP_OK)
    {
        Serial.println("CAN Driver start success...");
    }
    else
    {
        Serial.println("CAN Driver start FAILED...");
        return;
    }
}

//=======================================================================

void loop()
{
     can_message_t rx_frame;
    if (can_receive(&rx_frame, pdMS_TO_TICKS(1000)) == ESP_OK)
    {
    //do whatever you need with your received CAN messages here
    // follow the can_message_t struct to learn how to decode/process the received frame.
    }
    
     if (millis() - previousMillis > interval)  // send out your CAN frame once every second
        { 
            previousMillis = millis();
            can_transmit(&myMessageToSend, pdMS_TO_TICKS(1000));
      }
}

Code: Select all

can_message_t my_message = {
	.identifier = 0xABCD,
	.data_length_code = 8,
	.flags = CAN_MSG_FLAG_EXTD | CAN_MSG_FLAG_SS,
	.data = {1, 2 , 3 , 4 ,5 ,6 ,7 ,8}
};