When i setup a baud rate of 500Kbps in TWAI config i get data from car. But when i set any other baud rate the twai netwok start to get BUS error in another can logger.
So when i disconnect the TX wire on my CAN trasnreiever ic from ESP these errors goes away, so something is there which is still sending data to can network in TWAI api listen mode example.
Here is the code
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/* TWAI Network Listen Only Example
This example code is in the Public Domain (or CC0 licensed, at your option.)
Unless required by applicable law or agreed to in writing, this
software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
CONDITIONS OF ANY KIND, either express or implied.
*/
/*
* The following example demonstrates a Listen Only node in a TWAI network. The
* Listen Only node will not take part in any TWAI bus activity (no acknowledgments
* and no error frames). This example will execute multiple iterations, with each
* iteration the Listen Only node will do the following:
* 1) Listen for ping and ping response
* 2) Listen for start command
* 3) Listen for data messages
* 4) Listen for stop and stop response
*/
#include <stdio.h>
#include <stdlib.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "freertos/semphr.h"
#include "esp_err.h"
#include "esp_log.h"
#include "driver/twai.h"
/* --------------------- Definitions and static variables ------------------ */
//Example Configuration
#define NO_OF_ITERS 3
#define RX_TASK_PRIO 9
#define TX_GPIO_NUM CONFIG_EXAMPLE_TX_GPIO_NUM
#define RX_GPIO_NUM CONFIG_EXAMPLE_RX_GPIO_NUM
#define EXAMPLE_TAG "TWAI Listen Only"
#define ID_MASTER_STOP_CMD 0x0A0
#define ID_MASTER_START_CMD 0x0A1
#define ID_MASTER_PING 0x0A2
#define ID_SLAVE_STOP_RESP 0x0B0
#define ID_SLAVE_DATA 0x0B1
#define ID_SLAVE_PING_RESP 0x0B2
static const twai_filter_config_t f_config = TWAI_FILTER_CONFIG_ACCEPT_ALL();
static const twai_timing_config_t t_config = TWAI_TIMING_CONFIG_25KBITS();
//Set TX queue length to 0 due to listen only mode
static const twai_general_config_t g_config = {.mode = TWAI_MODE_LISTEN_ONLY,
.tx_io = TX_GPIO_NUM, .rx_io = RX_GPIO_NUM,
.clkout_io = TWAI_IO_UNUSED, .bus_off_io = TWAI_IO_UNUSED,
.tx_queue_len = 0, .rx_queue_len = 5,
.alerts_enabled = TWAI_ALERT_NONE,
.clkout_divider = 0};
static SemaphoreHandle_t rx_sem;
/* --------------------------- Tasks and Functions -------------------------- */
static void twai_receive_task(void *arg)
{
xSemaphoreTake(rx_sem, portMAX_DELAY);
bool start_cmd = false;
bool stop_resp = false;
uint32_t iterations = 0;
while (iterations < NO_OF_ITERS) {
twai_message_t rx_msg;
twai_receive(&rx_msg, portMAX_DELAY);
if (rx_msg.identifier == ID_MASTER_PING) {
ESP_LOGI(EXAMPLE_TAG, "Received master ping");
} else if (rx_msg.identifier == ID_SLAVE_PING_RESP) {
ESP_LOGI(EXAMPLE_TAG, "Received slave ping response");
} else if (rx_msg.identifier == ID_MASTER_START_CMD) {
ESP_LOGI(EXAMPLE_TAG, "Received master start command");
start_cmd = true;
} else if (rx_msg.identifier == ID_SLAVE_DATA) {
uint32_t data = 0;
for (int i = 0; i < rx_msg.data_length_code; i++) {
data |= (rx_msg.data[i] << (i * 8));
}
ESP_LOGI(EXAMPLE_TAG, "Received data value %d", data);
} else if (rx_msg.identifier == ID_MASTER_STOP_CMD) {
ESP_LOGI(EXAMPLE_TAG, "Received master stop command");
} else if (rx_msg.identifier == ID_SLAVE_STOP_RESP) {
ESP_LOGI(EXAMPLE_TAG, "Received slave stop response");
stop_resp = true;
}
if (start_cmd && stop_resp) {
//Each iteration is complete after a start command and stop response is received
iterations++;
start_cmd = 0;
stop_resp = 0;
}
}
xSemaphoreGive(rx_sem);
vTaskDelete(NULL);
}
void app_main(void)
{
rx_sem = xSemaphoreCreateBinary();
xTaskCreatePinnedToCore(twai_receive_task, "TWAI_rx", 4096, NULL, RX_TASK_PRIO, NULL, tskNO_AFFINITY);
//Install and start TWAI driver
ESP_ERROR_CHECK(twai_driver_install(&g_config, &t_config, &f_config));
ESP_LOGI(EXAMPLE_TAG, "Driver installed");
ESP_ERROR_CHECK(twai_start());
ESP_LOGI(EXAMPLE_TAG, "Driver started");
xSemaphoreGive(rx_sem); //Start RX task
vTaskDelay(pdMS_TO_TICKS(100));
xSemaphoreTake(rx_sem, portMAX_DELAY); //Wait for RX task to complete
//Stop and uninstall TWAI driver
ESP_ERROR_CHECK(twai_stop());
ESP_LOGI(EXAMPLE_TAG, "Driver stopped");
ESP_ERROR_CHECK(twai_driver_uninstall());
ESP_LOGI(EXAMPLE_TAG, "Driver uninstalled");
//Cleanup
vSemaphoreDelete(rx_sem);
}