124 lines
4.7 KiB
C
124 lines
4.7 KiB
C
/* CAN Network Listen Only Example
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This example code is in the Public Domain (or CC0 licensed, at your option.)
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Unless required by applicable law or agreed to in writing, this
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software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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CONDITIONS OF ANY KIND, either express or implied.
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*/
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/*
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* The following example demonstrates a Listen Only node in a CAN network. The
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* Listen Only node will not take part in any CAN bus activity (no acknowledgments
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* and no error frames). This example will execute multiple iterations, with each
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* iteration the Listen Only node will do the following:
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* 1) Listen for ping and ping response
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* 2) Listen for start command
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* 3) Listen for data messages
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* 4) Listen for stop and stop response
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "freertos/queue.h"
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#include "freertos/semphr.h"
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#include "esp_err.h"
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#include "esp_log.h"
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#include "driver/can.h"
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/* --------------------- Definitions and static variables ------------------ */
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//Example Configuration
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#define NO_OF_ITERS 3
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#define RX_TASK_PRIO 9
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#define TX_GPIO_NUM 21
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#define RX_GPIO_NUM 22
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#define EXAMPLE_TAG "CAN Listen Only"
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#define ID_MASTER_STOP_CMD 0x0A0
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#define ID_MASTER_START_CMD 0x0A1
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#define ID_MASTER_PING 0x0A2
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#define ID_SLAVE_STOP_RESP 0x0B0
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#define ID_SLAVE_DATA 0x0B1
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#define ID_SLAVE_PING_RESP 0x0B2
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static const can_filter_config_t f_config = CAN_FILTER_CONFIG_ACCEPT_ALL();
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static const can_timing_config_t t_config = CAN_TIMING_CONFIG_25KBITS();
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//Set TX queue length to 0 due to listen only mode
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static const can_general_config_t g_config = {.mode = CAN_MODE_LISTEN_ONLY,
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.tx_io = TX_GPIO_NUM, .rx_io = RX_GPIO_NUM,
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.clkout_io = CAN_IO_UNUSED, .bus_off_io = CAN_IO_UNUSED,
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.tx_queue_len = 0, .rx_queue_len = 5,
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.alerts_enabled = CAN_ALERT_NONE,
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.clkout_divider = 0};
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static SemaphoreHandle_t rx_sem;
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/* --------------------------- Tasks and Functions -------------------------- */
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static void can_receive_task(void *arg)
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{
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xSemaphoreTake(rx_sem, portMAX_DELAY);
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bool start_cmd = false;
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bool stop_resp = false;
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uint32_t iterations = 0;
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while (iterations < NO_OF_ITERS) {
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can_message_t rx_msg;
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can_receive(&rx_msg, portMAX_DELAY);
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if (rx_msg.identifier == ID_MASTER_PING) {
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ESP_LOGI(EXAMPLE_TAG, "Received master ping");
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} else if (rx_msg.identifier == ID_SLAVE_PING_RESP) {
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ESP_LOGI(EXAMPLE_TAG, "Received slave ping response");
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} else if (rx_msg.identifier == ID_MASTER_START_CMD) {
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ESP_LOGI(EXAMPLE_TAG, "Received master start command");
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start_cmd = true;
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} else if (rx_msg.identifier == ID_SLAVE_DATA) {
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uint32_t data = 0;
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for (int i = 0; i < rx_msg.data_length_code; i++) {
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data |= (rx_msg.data[i] << (i * 8));
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}
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ESP_LOGI(EXAMPLE_TAG, "Received data value %d", data);
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} else if (rx_msg.identifier == ID_MASTER_STOP_CMD) {
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ESP_LOGI(EXAMPLE_TAG, "Received master stop command");
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} else if (rx_msg.identifier == ID_SLAVE_STOP_RESP) {
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ESP_LOGI(EXAMPLE_TAG, "Received slave stop response");
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stop_resp = true;
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}
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if (start_cmd && stop_resp) {
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//Each iteration is complete after a start command and stop response is received
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iterations++;
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start_cmd = 0;
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stop_resp = 0;
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}
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}
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xSemaphoreGive(rx_sem);
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vTaskDelete(NULL);
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}
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void app_main(void)
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{
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rx_sem = xSemaphoreCreateBinary();
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xTaskCreatePinnedToCore(can_receive_task, "CAN_rx", 4096, NULL, RX_TASK_PRIO, NULL, tskNO_AFFINITY);
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//Install and start CAN driver
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ESP_ERROR_CHECK(can_driver_install(&g_config, &t_config, &f_config));
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ESP_LOGI(EXAMPLE_TAG, "Driver installed");
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ESP_ERROR_CHECK(can_start());
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ESP_LOGI(EXAMPLE_TAG, "Driver started");
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xSemaphoreGive(rx_sem); //Start RX task
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vTaskDelay(pdMS_TO_TICKS(100));
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xSemaphoreTake(rx_sem, portMAX_DELAY); //Wait for RX task to complete
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//Stop and uninstall CAN driver
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ESP_ERROR_CHECK(can_stop());
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ESP_LOGI(EXAMPLE_TAG, "Driver stopped");
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ESP_ERROR_CHECK(can_driver_uninstall());
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ESP_LOGI(EXAMPLE_TAG, "Driver uninstalled");
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//Cleanup
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vSemaphoreDelete(rx_sem);
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}
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