玩iot camera笔记之3测试试用3路pwm

发布于 2016-09-19 16:44:00 浏览：2914 订阅该版

**在测试PWM的时候，发现只能启动PWM0,PWM1 PWM2 启动失败，求大神（已解决！根据网友提示并参考lua pwm库）**
代码放在 firmware-20160908applicationsmain.c
里面，添加对应所需的头文件
```/* pwm init test
 *
 *
 *
 * */
#include <rtdevice.h>
#include <drivers/pwm.h>
#include <finsh.h>```

在main函数后面添加代码并添加到main函数里面，以便启动完 /init.sh脚本后，启动我的测试pwm

```

int pwmSet()
{
	rt_device_t pwm_dev;
	struct pwm_device pwm;
	int ret;
	pwm_dev = rt_device_find("pwm");
	rt_kprintf("pwm_dev->device_id = %d 
" , pwm_dev->device_id);
	ret = rt_device_open(pwm_dev, RT_DEVICE_OFLAG_RDWR);
	rt_kprintf("rt_device_open end
");

/* 打开设备时就使能了
	ret = rt_device_control(pwm_dev, ENABLE_PWM, &pwm);
	rt_kprintf("ENABLE_PWM end
");
	*/

//ret = rt_device_control(pwm_dev, GET_PWM_DUTY_CYCLE, &pwm);
	pwm.id=0;//pwm0
	pwm.working= 1;
	//38kHz =26.3
	pwm.counter_ns = 13000;//for duty
	pwm.period_ns = 26000;
	ret = rt_device_control(pwm_dev, SET_PWM_DUTY_CYCLE, &pwm);
	rt_kprintf("SET_PWM_DUTY_CYCLE end
");

#if 1
	ret = rt_device_control(pwm_dev, GET_PWM_DUTY_CYCLE, &pwm);
	rt_kprintf("GET_PWM_DUTY_CYCLE id= %d pwm.counter_ns = %d pwm.period_ns = %d
" , pwm.id,pwm.counter_ns , pwm.period_ns);
#endif

#if 1
	pwm.id=1;//pwm1
	pwm.working= 1;
	//38kHz =26.3
	pwm.counter_ns = 13000;//for duty
	pwm.period_ns = 26000;
	ret = rt_device_control(pwm_dev, SET_PWM_DUTY_CYCLE, &pwm);
	rt_kprintf("SET_PWM_DUTY_CYCLE pwm1 end
");

#endif

}
MSH_CMD_EXPORT(pwmSet, pwmSet);

```

然后让系统启动后自动启动pwm，在main函数的return 前面添加一行
```	pwmSet();

return 0;```

重新编译并启动，发现PWM0有输出38KHZ的方波，但是隔壁的PWM1 PWM2 都是低电平,没反应，难道芯片挂了？
求救啊