154 lines
5.7 KiB
C
154 lines
5.7 KiB
C
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/* CAN Alert and Recovery 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 how to use the alert and bus recovery
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* features of the CAN driver. The example will do the following:
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* 1) Install and start the CAN driver
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* 2) Have the TX task periodically broadcast messages expecting no ACK
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* 3) Reconfigure alerts to detect bus-off state
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* 4) Trigger bus errors by inverting TX GPIO
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* 5) Initiate bus-off recovery and wait for completion
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* 6) Uninstall CAN driver
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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/semphr.h"
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#include "esp_err.h"
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#include "esp_log.h"
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#include "driver/gpio.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 TX_GPIO_NUM 21
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#define RX_GPIO_NUM 22
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#define TX_TASK_PRIO 9
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#define CTRL_TASK_PRIO 10
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#define ERR_DELAY_US 800 //Approximate time for arbitration phase at 25KBPS
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#define ERR_PERIOD_US 80 //Approximate time for two bits at 25KBPS
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#define EXAMPLE_TAG "CAN Alert and Recovery"
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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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static const can_general_config_t g_config = CAN_GENERAL_CONFIG_DEFAULT(TX_GPIO_NUM, RX_GPIO_NUM, CAN_MODE_NO_ACK);
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static const can_message_t tx_msg = {.identifier = 0, .data_length_code = 0, .flags = CAN_MSG_FLAG_NONE};
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static SemaphoreHandle_t tx_task_sem;
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static SemaphoreHandle_t ctrl_task_sem;
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static bool trigger_tx_error = false;
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/* --------------------------- Tasks and Functions -------------------------- */
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static void invert_tx_bits(bool enable)
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{
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if (enable) {
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//Inverts output of TX to trigger errors
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gpio_matrix_out(TX_GPIO_NUM, CAN_TX_IDX, true, false);
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} else {
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//Returns TX to default settings
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gpio_matrix_out(TX_GPIO_NUM, CAN_TX_IDX, false, false);
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}
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}
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static void tx_task(void *arg)
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{
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xSemaphoreTake(tx_task_sem, portMAX_DELAY);
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while (1) {
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if (can_transmit(&tx_msg, 0) == ESP_ERR_INVALID_STATE) {
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break; //Exit TX task when bus-off state is reached
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}
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if (trigger_tx_error) {
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//Trigger a bit error in transmission by inverting GPIO
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ets_delay_us(ERR_DELAY_US); //Wait until arbitration phase is over
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invert_tx_bits(true); //Trigger bit error for a few bits
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ets_delay_us(ERR_PERIOD_US);
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invert_tx_bits(false);
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}
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vTaskDelay(pdMS_TO_TICKS(50));
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}
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vTaskDelete(NULL);
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}
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static void ctrl_task(void *arg)
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{
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xSemaphoreTake(ctrl_task_sem, portMAX_DELAY);
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ESP_ERROR_CHECK(can_start());
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ESP_LOGI(EXAMPLE_TAG, "Driver started");
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ESP_LOGI(EXAMPLE_TAG, "Starting transmissions");
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xSemaphoreGive(tx_task_sem); //Start transmit task
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//Prepare to trigger errors, reconfigure alerts to detect change in error state
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can_reconfigure_alerts(CAN_ALERT_ABOVE_ERR_WARN | CAN_ALERT_ERR_PASS | CAN_ALERT_BUS_OFF, NULL);
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for (int i = 3; i > 0; i--) {
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ESP_LOGW(EXAMPLE_TAG, "Trigger TX errors in %d", i);
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vTaskDelay(pdMS_TO_TICKS(1000));
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}
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ESP_LOGI(EXAMPLE_TAG, "Trigger errors");
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trigger_tx_error = true;
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while (1) {
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uint32_t alerts;
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can_read_alerts(&alerts, portMAX_DELAY);
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if (alerts & CAN_ALERT_ABOVE_ERR_WARN) {
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ESP_LOGI(EXAMPLE_TAG, "Surpassed Error Warning Limit");
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}
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if (alerts & CAN_ALERT_ERR_PASS) {
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ESP_LOGI(EXAMPLE_TAG, "Entered Error Passive state");
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}
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if (alerts & CAN_ALERT_BUS_OFF) {
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ESP_LOGI(EXAMPLE_TAG, "Bus Off state");
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//Prepare to initiate bus recovery, reconfigure alerts to detect bus recovery completion
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can_reconfigure_alerts(CAN_ALERT_BUS_RECOVERED, NULL);
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for (int i = 3; i > 0; i--) {
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ESP_LOGW(EXAMPLE_TAG, "Initiate bus recovery in %d", i);
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vTaskDelay(pdMS_TO_TICKS(1000));
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}
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can_initiate_recovery(); //Needs 128 occurrences of bus free signal
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ESP_LOGI(EXAMPLE_TAG, "Initiate bus recovery");
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}
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if (alerts & CAN_ALERT_BUS_RECOVERED) {
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//Bus recovery was successful, exit control task to uninstall driver
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ESP_LOGI(EXAMPLE_TAG, "Bus Recovered");
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break;
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}
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}
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//No need call can_stop(), bus recovery will return to stopped state
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xSemaphoreGive(ctrl_task_sem);
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vTaskDelete(NULL);
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}
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void app_main()
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{
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tx_task_sem = xSemaphoreCreateBinary();
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ctrl_task_sem = xSemaphoreCreateBinary();
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xTaskCreatePinnedToCore(tx_task, "CAN_tx", 4096, NULL, TX_TASK_PRIO, NULL, tskNO_AFFINITY);
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xTaskCreatePinnedToCore(ctrl_task, "CAN_ctrl", 4096, NULL, CTRL_TASK_PRIO, NULL, tskNO_AFFINITY);
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//Install 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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xSemaphoreGive(ctrl_task_sem); //Start control task
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vTaskDelay(pdMS_TO_TICKS(100));
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xSemaphoreTake(ctrl_task_sem, portMAX_DELAY); //Wait for completion
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//Uninstall CAN driver
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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(tx_task_sem);
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vSemaphoreDelete(ctrl_task_sem);
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}
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