gptimer: add example with various use cases

examples/peripherals/timer_group/gptimer/main/gptimer_example_main.c

@@ -0,0 +1,155 @@
+/*
+ * SPDX-FileCopyrightText: 2010-2022 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: CC0-1.0
+ */
+
+#include <stdio.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/queue.h"
+#include "driver/gptimer.h"
+#include "esp_log.h"
+
+static const char *TAG = "example";
+
+typedef struct {
+    uint64_t event_count;
+} example_queue_element_t;
+
+static bool IRAM_ATTR example_timer_on_alarm_cb_v1(gptimer_handle_t timer, const gptimer_alarm_event_data_t *edata, void *user_data)
+{
+    BaseType_t high_task_awoken = pdFALSE;
+    QueueHandle_t queue = (QueueHandle_t)user_data;
+    // stop timer immediately
+    gptimer_stop(timer);
+    // Retrieve count value and send to queue
+    example_queue_element_t ele = {
+        .event_count = edata->count_value
+    };
+    xQueueSendFromISR(queue, &ele, &high_task_awoken);
+    // return whether we need to yield at the end of ISR
+    return (high_task_awoken == pdTRUE);
+}
+
+static bool IRAM_ATTR example_timer_on_alarm_cb_v2(gptimer_handle_t timer, const gptimer_alarm_event_data_t *edata, void *user_data)
+{
+    BaseType_t high_task_awoken = pdFALSE;
+    QueueHandle_t queue = (QueueHandle_t)user_data;
+    // Retrieve count value and send to queue
+    example_queue_element_t ele = {
+        .event_count = edata->count_value
+    };
+    xQueueSendFromISR(queue, &ele, &high_task_awoken);
+    // return whether we need to yield at the end of ISR
+    return (high_task_awoken == pdTRUE);
+}
+
+static bool IRAM_ATTR example_timer_on_alarm_cb_v3(gptimer_handle_t timer, const gptimer_alarm_event_data_t *edata, void *user_data)
+{
+    BaseType_t high_task_awoken = pdFALSE;
+    QueueHandle_t queue = (QueueHandle_t)user_data;
+    // Retrieve count value and send to queue
+    example_queue_element_t ele = {
+        .event_count = edata->count_value
+    };
+    xQueueSendFromISR(queue, &ele, &high_task_awoken);
+    // reconfigure alarm value
+    gptimer_alarm_config_t alarm_config = {
+        .alarm_count = edata->alarm_value + 1000000, // alarm in next 1s
+    };
+    gptimer_set_alarm_action(timer, &alarm_config);
+    // return whether we need to yield at the end of ISR
+    return (high_task_awoken == pdTRUE);
+}
+
+void app_main(void)
+{
+    example_queue_element_t ele;
+    QueueHandle_t queue = xQueueCreate(10, sizeof(example_queue_element_t));
+    if (!queue) {
+        ESP_LOGE(TAG, "Creating queue failed");
+        return;
+    }
+
+    ESP_LOGI(TAG, "Create timer handle");
+    gptimer_handle_t gptimer = NULL;
+    gptimer_config_t timer_config = {
+        .clk_src = GPTIMER_CLK_SRC_APB,
+        .direction = GPTIMER_COUNT_UP,
+        .resolution_hz = 1000000, // 1MHz, 1 tick=1us
+    };
+    ESP_ERROR_CHECK(gptimer_new_timer(&timer_config, &gptimer));
+
+    gptimer_event_callbacks_t cbs = {
+        .on_alarm = example_timer_on_alarm_cb_v1,
+    };
+    ESP_ERROR_CHECK(gptimer_register_event_callbacks(gptimer, &cbs, queue));
+
+    ESP_LOGI(TAG, "Start timer, stop it at alarm event");
+    gptimer_alarm_config_t alarm_config1 = {
+        .alarm_count = 1000000, // period = 1s
+    };
+    ESP_ERROR_CHECK(gptimer_set_alarm_action(gptimer, &alarm_config1));
+    ESP_ERROR_CHECK(gptimer_start(gptimer));
+    if (xQueueReceive(queue, &ele, pdMS_TO_TICKS(2000))) {
+        ESP_LOGI(TAG, "Timer stopped, count=%llu", ele.event_count);
+    } else {
+        ESP_LOGW(TAG, "Missed one count event");
+    }
+
+    ESP_LOGI(TAG, "Set count value");
+    ESP_ERROR_CHECK(gptimer_set_raw_count(gptimer, 100));
+    ESP_LOGI(TAG, "Get count value");
+    uint64_t count;
+    ESP_ERROR_CHECK(gptimer_get_raw_count(gptimer, &count));
+    ESP_LOGI(TAG, "Timer count value=%llu", count);
+
+    ESP_LOGI(TAG, "Start timer, auto-reload at alarm event");
+    cbs.on_alarm = example_timer_on_alarm_cb_v2;
+    ESP_ERROR_CHECK(gptimer_register_event_callbacks(gptimer, &cbs, queue));
+    gptimer_alarm_config_t alarm_config2 = {
+        .reload_count = 0,
+        .alarm_count = 1000000, // period = 1s
+        .flags.auto_reload_on_alarm = true,
+    };
+    ESP_ERROR_CHECK(gptimer_set_alarm_action(gptimer, &alarm_config2));
+    ESP_ERROR_CHECK(gptimer_start(gptimer));
+    int record = 4;
+    while (record) {
+        if (xQueueReceive(queue, &ele, pdMS_TO_TICKS(2000))) {
+            ESP_LOGI(TAG, "Timer reloaded, count=%llu", ele.event_count);
+            record--;
+        } else {
+            ESP_LOGW(TAG, "Missed one count event");
+        }
+    }
+
+    ESP_LOGI(TAG, "Stop timer");
+    ESP_ERROR_CHECK(gptimer_stop(gptimer));
+
+    ESP_LOGI(TAG, "Update alarm value dynamically");
+    cbs.on_alarm = example_timer_on_alarm_cb_v3;
+    ESP_ERROR_CHECK(gptimer_register_event_callbacks(gptimer, &cbs, queue));
+    gptimer_alarm_config_t alarm_config3 = {
+        .alarm_count = 1000000, // period = 1s
+    };
+    ESP_ERROR_CHECK(gptimer_set_alarm_action(gptimer, &alarm_config3));
+    ESP_ERROR_CHECK(gptimer_start(gptimer));
+    record = 4;
+    while (record) {
+        if (xQueueReceive(queue, &ele, pdMS_TO_TICKS(2000))) {
+            ESP_LOGI(TAG, "Timer alarmed, count=%llu", ele.event_count);
+            record--;
+        } else {
+            ESP_LOGW(TAG, "Missed one count event");
+        }
+    }
+
+    ESP_LOGI(TAG, "Stop timer");
+    ESP_ERROR_CHECK(gptimer_stop(gptimer));
+    ESP_LOGI(TAG, "Delete timer");
+    ESP_ERROR_CHECK(gptimer_del_timer(gptimer));
+
+    vQueueDelete(queue);
+}