4.硬件定時器的使用和學習

這里依然使用mdk的看法環(huán)境，使用mdk編譯程序，下載程序

4.1配置使能硬件定時器2

4.2 編寫定時器的測試函數

/*

程序清單：這是一個 hwtimer 設備使用例程
例程導出了 hwtimer_sample 命令到控制終端
命令調用格式：hwtimer_sample
程序功能：硬件定時器超時回調函數周期性的打印當前tick值，2次tick值之差換算為時間等同于定時時間值。
/
#include
#include
#define HWTIMER_DEV_NAME "time2" / 定時器名稱 /
/ 定時器超時回調函數 /
static rt_err_t timeout_cb(rt_device_t dev, rt_size_t size)
{
rt_kprintf("this is hwtimer timeout callback fucntion!n");
rt_kprintf("tick is :%d !n", rt_tick_get());
return 0;
}
int hwtimer_sample(void)
{
rt_err_t ret = RT_EOK;
rt_hwtimerval_t timeout_s; / 定時器超時值 /
rt_device_t hw_dev = RT_NULL; / 定時器設備句柄 /
rt_hwtimer_mode_t mode; / 定時器模式 /
rt_uint32_t freq = 10000; / 計數頻率 /
/ 查找定時器設備 /
hw_dev = rt_device_find(HWTIMER_DEV_NAME);
if (hw_dev == RT_NULL)
{
rt_kprintf("hwtimer sample run failed! can't find %s device!n", HWTIMER_DEV_NAME);
return RT_ERROR;
}
/ 以讀寫方式打開設備 /
ret = rt_device_open(hw_dev, RT_DEVICE_OFLAG_RDWR);
if (ret != RT_EOK)
{
rt_kprintf("open %s device failed!n", HWTIMER_DEV_NAME);
return ret;
}
/ 設置超時回調函數 /
rt_device_set_rx_indicate(hw_dev, timeout_cb);
/ 設置計數頻率(若未設置該項，默認為1Mhz 或 支持的最小計數頻率) /
rt_device_control(hw_dev, HWTIMER_CTRL_FREQ_SET, &freq);
/ 設置模式為周期性定時器（若未設置，默認是HWTIMER_MODE_ONESHOT）/
mode = HWTIMER_MODE_PERIOD;
ret = rt_device_control(hw_dev, HWTIMER_CTRL_MODE_SET, &mode);
if (ret != RT_EOK)
{
rt_kprintf("set mode failed! ret is :%dn", ret);
return ret;
}
/ 設置定時器超時值為5s并啟動定時器 /
timeout_s.sec = 5; / 秒 /
timeout_s.usec = 0; / 微秒 /
if (rt_device_write(hw_dev, 0, &timeout_s, sizeof(timeout_s)) != sizeof(timeout_s))
{
rt_kprintf("set timeout value failedn");
return RT_ERROR;
}
/ 延時3500ms /
rt_thread_mdelay(3500);
/ 讀取定時器當前值 /
rt_device_read(hw_dev, 0, &timeout_s, sizeof(timeout_s));
rt_kprintf("Read: Sec = %d, Usec = %dn", timeout_s.sec, timeout_s.usec);
return ret;
}
/ 導出到 msh 命令列表中 */
MSH_CMD_EXPORT(hwtimer_sample, hwtimer sample);

4.3測試函數，查看運行結果

4.4硬件定時器設備驅動框架學習

使用方法：

4.4.1實現定時器的各個操作函數

/*

1. 定時器 初始化函數
2. 定時器起始函數
3. 定時器停止函數
4. 定時器的計數值獲取
5. 定時器的控制函數
   */
   struct rt_hwtimer_ops
   {
   void (*init)(struct rt_hwtimer_device *timer, rt_uint32_t state);
   rt_err_t (*start)(struct rt_hwtimer_device *timer, rt_uint32_t cnt, rt_hwtimer_mode_t mode);
   void (*stop)(struct rt_hwtimer_device *timer);
   rt_uint32_t (*count_get)(struct rt_hwtimer_device *timer);
   rt_err_t (*control)(struct rt_hwtimer_device *timer, rt_uint32_t cmd, void args);
   };
   4.4.2配置定時器的基本參數
   / 定時器特征描述 Timer Feature Information /
   struct rt_hwtimer_info
   {
   rt_int32_t maxfreq; / 最大頻率 the maximum count frequency timer support /
   rt_int32_t minfreq; / 最小頻率 the minimum count frequency timer support /
   rt_uint32_t maxcnt; / 最大計數 值counter maximum value /
   rt_uint8_t cntmode; / 計數方向 count mode (inc/dec) */
   };
   typedef struct rt_hwtimer_device
   {
   struct rt_device parent;//基本設備驅動框架
   const struct rt_hwtimer_ops *ops;//定時器特有的操作函數
   const struct rt_hwtimer_info info;//定時器相關的參數信息
   rt_int32_t freq; / 用戶設置的計數頻率 counting frequency set by the user /
   rt_int32_t overflow; / 定時器溢出 timer overflows /
   float period_sec;
   rt_int32_t cycles; / 溢出后將生成超時事件多少次 how many times will generate a timeout event after overflow /
   rt_int32_t reload; / 重新加載循環(huán)（使用周期模式） reload cycles(using in period mode) /
   rt_hwtimer_mode_t mode; / 計時模式（一次/周期） timing mode(oneshot/period) /
   } rt_hwtimer_t;
   4.4.3注冊定時器的設備到驅動框架
   /
   定時器設備注冊函數
   */
   rt_err_t rt_device_hwtimer_register(rt_hwtimer_t *timer, const char *name, void *user_data);

4.4.4詳細的定時器設備驅動相關

/*

Copyright (c) 2006-2023, RT-Thread Development Team

SPDX-License-Identifier: Apache-2.0

Change Logs:
Date Author Notes
/
#ifndef HWTIMER_H
#define HWTIMER_H
#include
#ifdef __cplusplus
extern "C" {
#endif
/ 定時器的控制命令類型 /
typedef enum
{
HWTIMER_CTRL_FREQ_SET = RT_DEVICE_CTRL_BASE(Timer) + 0x01, / 設置技術的頻率set the count frequency /
HWTIMER_CTRL_STOP = RT_DEVICE_CTRL_BASE(Timer) + 0x02, / 停止定時器stop timer /
HWTIMER_CTRL_INFO_GET = RT_DEVICE_CTRL_BASE(Timer) + 0x03, / 獲取計時器功能信息 get a timer feature information /
HWTIMER_CTRL_MODE_SET = RT_DEVICE_CTRL_BASE(Timer) + 0x04 / 設置定時器的工作模式 Setting the timing mode(oneshot/period) /
} rt_hwtimer_ctrl_t;
/ Timing Mode /
typedef enum
{
HWTIMER_MODE_ONESHOT = 0x01,//單次模式
HWTIMER_MODE_PERIOD//周期模式
} rt_hwtimer_mode_t;
/ Time Value /
typedef struct rt_hwtimerval
{
rt_int32_t sec; / 秒 second /
rt_int32_t usec; / 微秒 microsecond /
} rt_hwtimerval_t;
/ 計數的方向 /
#define HWTIMER_CNTMODE_UP 0x01 / increment count mode /
#define HWTIMER_CNTMODE_DW 0x02 / decreasing count mode /
struct rt_hwtimer_device;
/

1. 定時器 初始化函數
2. 定時器起始函數
3. 定時器停止函數
4. 定時器的計數值獲取
5. 定時器的控制函數
   */
   struct rt_hwtimer_ops
   {
   void (*init)(struct rt_hwtimer_device *timer, rt_uint32_t state);
   rt_err_t (*start)(struct rt_hwtimer_device *timer, rt_uint32_t cnt, rt_hwtimer_mode_t mode);
   void (*stop)(struct rt_hwtimer_device *timer);
   rt_uint32_t (*count_get)(struct rt_hwtimer_device *timer);
   rt_err_t (*control)(struct rt_hwtimer_device *timer, rt_uint32_t cmd, void args);
   };
   / 定時器特征描述 Timer Feature Information /
   struct rt_hwtimer_info
   {
   rt_int32_t maxfreq; / 最大頻率 the maximum count frequency timer support /
   rt_int32_t minfreq; / 最小頻率 the minimum count frequency timer support /
   rt_uint32_t maxcnt; / 最大計數 值counter maximum value /
   rt_uint8_t cntmode; / 計數方向 count mode (inc/dec) */
   };
   typedef struct rt_hwtimer_device
   {
   struct rt_device parent;//基本設備驅動框架
   const struct rt_hwtimer_ops *ops;//定時器特有的操作函數
   const struct rt_hwtimer_info info;//定時器相關的參數信息
   rt_int32_t freq; / 用戶設置的計數頻率 counting frequency set by the user /
   rt_int32_t overflow; / 定時器溢出 timer overflows /
   float period_sec;
   rt_int32_t cycles; / 溢出后將生成超時事件多少次 how many times will generate a timeout event after overflow /
   rt_int32_t reload; / 重新加載循環(huán)（使用周期模式） reload cycles(using in period mode) /
   rt_hwtimer_mode_t mode; / 計時模式（一次/周期） timing mode(oneshot/period) /
   } rt_hwtimer_t;
   /
   定時器設備注冊函數
   */
   rt_err_t rt_device_hwtimer_register(rt_hwtimer_t *timer, const char *name, void *user_data);
   / 定時器回調函數 /
   void rt_device_hwtimer_isr(rt_hwtimer_t *timer);
   #ifdef __cplusplus
   }
   #endif
   #endif