【乐鑫ESP32-C3 RISC-V处理器IoT开发板试用体验】---定时器

ti

一、示范

1.简介：使用~esp-idfexamplesperipheralstimer_group例程；使用前将此工程复制到自己创建的工程文件夹中；

2.功能：定时器组[0]的定时器0的每隔3s打印一次；定时器组[1]的定时器0的每隔5s打印一次；

二、代码

1.

/* General Purpose Timer 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.
*/
#include
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "driver/timer.h"
#define TIMER_DIVIDER (16) // Hardware timer clock divider
#define TIMER_SCALE (TIMER_BASE_CLK / TIMER_DIVIDER) // convert counter value to seconds
//按照定时器定义的结构体：定时器组，中定时器，报警时间（也就是定时器事件后发生中断），是否有自动重装
typedef struct {
int timer_group;
int timer_idx;
int alarm_interval;
bool auto_reload;
} example_timer_info_t;
/**
* [url=home.php?mod=space&uid=2666770]@Brief[/url] A sample structure to pass events from the timer ISR to task
*
*/
//定义的一个示例结构体，除了包含定时器的参数外，还定义了一个用于存储定时器中计数器数值的变量
typedef struct {
example_timer_info_t info;
uint64_t timer_counter_value;
} example_timer_event_t;
static xQueueHandle s_timer_queue;
/*
* A simple helper function to print the raw timer counter value
* and the counter value converted to seconds
*/
static void inline print_timer_counter(uint64_t counter_value)
{
printf("Counter: 0x%08x%08xrn", (uint32_t) (counter_value >> 32),
(uint32_t) (counter_value));
printf("Time : %.8f srn", (double) counter_value / TIMER_SCALE);
}
static bool IRAM_ATTR timer_group_isr_callback(void *args)
{
BaseType_t high_task_awoken = pdFALSE;
example_timer_info_t *info = (example_timer_info_t *) args;
uint64_t timer_counter_value = timer_group_get_counter_value_in_isr(info->timer_group, info->timer_idx);
/* Prepare basic event data that will be then sent back to task */
//将定时器中断响应的定时器赋予结构体变量evt
example_timer_event_t evt = {
.info.timer_group = info->timer_group,
.info.timer_idx = info->timer_idx,
.info.auto_reload = info->auto_reload,
.info.alarm_interval = info->alarm_interval,
.timer_counter_value = timer_counter_value
};
//判断定时器组，中的定时器，是否有自动重载
if (!info->auto_reload) {
timer_counter_value += info->alarm_interval * TIMER_SCALE;
//重新设置定时器组，中定时器，的时间间隔（定时器自身的时间间隔）
timer_group_set_alarm_value_in_isr(info->timer_group, info->timer_idx, timer_counter_value);
}
/* Now just send the event data back to the main program task */
//发送事件消息，消息存储在结构体evt中；注意：最后的参数提醒查看技术手册
xQueueSendFromISR(s_timer_queue, &evt, &high_task_awoken);
return high_task_awoken == pdTRUE; // return whether we need to yield at the end of ISR
}
/**
* @brief Initialize selected timer of timer group
*
* [url=home.php?mod=space&uid=3142012]@param[/url] group Timer Group number, index from 0
* @param timer timer ID, index from 0
* @param auto_reload whether auto-reload on alarm event
* @param timer_interval_sec interval of alarm
*/
static void example_tg_timer_init(int group, int timer, bool auto_reload, int timer_interval_sec)
{
/****************************************一、配置定时器结构体timer_config_t**************************************/
/* Select and initialize basic parameters of the timer */
timer_config_t config = {
.divider = TIMER_DIVIDER, //定时器预分频；esp32-c3的APB_CLK=80MHz，80MHz/TIMER_DIVIDER(16)=5MHz
.counter_dir = TIMER_COUNT_UP, //计数器向上计数，从0开始
.counter_en = TIMER_PAUSE, //计数器暂时中止
.alarm_en = TIMER_ALARM_EN, //定时器警报使能
.auto_reload = auto_reload, //1:定时器硬件在警报事件后自动重装载；0：则相反
}; // default clock source is APB
/****************************************二、timer_init函数中参数的定义******************************************/
/*
* 函数功能：Initializes and configure the timer.
* 参数1：group_num Timer group number, 0 for TIMERG0 or 1 for TIMERG1
* 参数2：timer_num Timer index, 0 for hw_timer[0] & 1 for hw_timer[1] 【一组定时器包含：普通定时器，看门狗定时器】
* 参数3：config Pointer to timer initialization parameters.
*/
timer_init(group, timer, &config); //定义定时器的工作方式,实现定时器初始化
/****************************************三、定时器计数器器值配置************************************************/
/* Timer's counter will initially start from value below.
Also, if auto_reload is set, this value will be automatically reload on alarm */
timer_set_counter_value(group, timer, 0); //配置定时器组（group），定时器x（timer）的计数器的值
/***************************************四、定时器警报值设置、并使能中断ISR**************************************/
/* Configure the alarm value and the interrupt on alarm. */
//【timer_interval_sec值有上层调用函数提供；TIMER_SCALE=TIMER_BASE_CLK / TIMER_DIVIDER=APB_CLK_FREQ/TIMER_DIVIDER=80MHz/16=5MHz】
timer_set_alarm_value(group, timer, timer_interval_sec * TIMER_SCALE);
timer_enable_intr(group, timer);//使能定时器组（group）、定时器x（timer）中断
/****************************************五、为对应的定时器添加ISR中断回调函数**************************************/
example_timer_info_t *timer_info = calloc(1, sizeof(example_timer_info_t));
timer_info->timer_group = group;
timer_info->timer_idx = timer;
timer_info->auto_reload = auto_reload;
timer_info->alarm_interval = timer_interval_sec;
timer_isr_callback_add(group, timer, timer_group_isr_callback, timer_info, 0);//???
/****************************************六、启动定时器*************************************************************/
timer_start(group, timer);//启动定时器组（group）、定时器x（timer）计数器
}
void app_main(void)
{
s_timer_queue = xQueueCreate(10, sizeof(example_timer_event_t));
//函数的意思：配置定时器组0，中的定时器0，自动重装，间隔是3s
example_tg_timer_init(TIMER_GROUP_0, TIMER_0, true, 3);
//函数的意思：配置定时器组1，中的定时器0，无自动重装，间隔是5s
example_tg_timer_init(TIMER_GROUP_1, TIMER_0, false, 5);
while (1) {
example_timer_event_t evt;
//等待队列事件，时间是永远等待
xQueueReceive(s_timer_queue, &evt, portMAX_DELAY);
/* Print information that the timer reported an event */
//判定定时器组是否有自动重装
if (evt.info.auto_reload) {
printf("Timer Group with auto reloadn");
} else {
printf("Timer Group without auto reloadn");
}
printf("Group[%d], timer[%d] alarm eventn", evt.info.timer_group, evt.info.timer_idx);
/* Print the timer values passed by event */
printf("------- EVENT TIME --------n");
print_timer_counter(evt.timer_counter_value);
/* Print the timer values as visible by this task */
printf("-------- TASK TIME --------n");
uint64_t task_counter_value;
//获取定时器组，中定时器，的计数器的值；
timer_get_counter_value(evt.info.timer_group, evt.info.timer_idx, &task_counter_value);
print_timer_counter(task_counter_value);
}
}