HWTIMER

通过硬件定时器超时回调函数周期性的打印当前 tick 值 更多...

通过硬件定时器超时回调函数周期性的打印当前 tick 值

源码

/*
 * Copyright (c) 2006-2018, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date Author Notes
 * 2018-11-30 misonyo first implementation.
 */
/*
 * 程序清单：这是一个 hwtimer 设备使用例程
 * 例程导出了 hwtimer_sample 命令到控制终端
 * 命令调用格式：hwtimer_sample
 * 程序功能：硬件定时器超时回调函数周期性的打印当前tick值，2次tick值之差换算为时间等同于定时时间值。
*/

#include <rtthread.h>
#include <rtdevice.h>

#define HWTIMER_DEV_NAME "timer0" /* 定时器名称 */

/* 定时器超时回调函数 */
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;
}

static int hwtimer_sample(int argc, char *argv[])
{
 rt_err_t ret = RT_EOK;
 rt_hwtimerval_t timeout_s; /* 定时器超时值 */
 rt_device_t hw_dev = RT_NULL; /* 定时器设备句柄 */
 rt_hwtimer_mode_t mode; /* 定时器模式 */
 rt_uint32_t freq = 10000; /* 计数频率 */

 /* 查找定时器设备 */
 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;
 }

 /* 以读写方式打开设备 */
 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;
 }

 /* 设置超时回调函数 */
 rt_device_set_rx_indicate(hw_dev, timeout_cb);

 /* 设置计数频率(默认1Mhz或支持的最小计数频率) */
 ret = rt_device_control(hw_dev, HWTIMER_CTRL_FREQ_SET, &freq);
 if (ret != RT_EOK)
 {
 rt_kprintf("set frequency failed! ret is :%d\n", ret);
 return ret;
 }

 /* 设置模式为周期性定时器 */
 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 :%d\n", ret);
 return ret;
 }

 /* 设置定时器超时值为5s并启动定时器 */
 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 failed\n");
 return RT_ERROR;
 }

 /* 延时3500ms */
 rt_thread_mdelay(3500);

 /* 读取定时器当前值 */
 rt_device_read(hw_dev, 0, &timeout_s, sizeof(timeout_s));
 rt_kprintf("Read: Sec = %d, Usec = %d\n", timeout_s.sec, timeout_s.usec);

 return ret;
}
/* 导出到 msh 命令列表中 */
MSH_CMD_EXPORT(hwtimer_sample, hwtimer sample);