pwm没有输出的解决办法

发布于 2020-09-22 14:15:19 浏览：2378 订阅该版

[tocm]

### stm32中使用pwm时存在问题，没有输出呀，其根本原因在于drv_pwm中没有打开时钟

```
static int stm32_pwm_init(void)
{
    int i = 0;
    int result = RT_EOK;

pwm_get_channel();

#ifdef BSP_USING_PWM1
    __HAL_RCC_TIM1_CLK_ENABLE();
#endif 	
#ifdef BSP_USING_PWM2
    __HAL_RCC_TIM2_CLK_ENABLE();
#endif 
#ifdef BSP_USING_PWM3
    __HAL_RCC_TIM3_CLK_ENABLE();
#endif 
#ifdef BSP_USING_PWM4
    __HAL_RCC_TIM4_CLK_ENABLE();
#endif

for (i = 0; i < sizeof(stm32_pwm_obj) / sizeof(stm32_pwm_obj[0]); i++)
    {
        /* pwm init */
        if (stm32_hw_pwm_init(&stm32_pwm_obj[i]) != RT_EOK)
        {
            LOG_E("%s init failed", stm32_pwm_obj[i].name);
            result = -RT_ERROR;
            goto __exit;
        }
        else
        {
            LOG_D("%s init success", stm32_pwm_obj[i].name);

/* register pwm device */
            if (rt_device_pwm_register(&stm32_pwm_obj[i].pwm_device, stm32_pwm_obj[i].name, &drv_ops, &stm32_pwm_obj[i].tim_handle) == RT_EOK)
            {
                LOG_D("%s register success", stm32_pwm_obj[i].name);
            }
            else
            {
                LOG_E("%s register failed", stm32_pwm_obj[i].name);
                result = -RT_ERROR;
            }
        }
    }

__exit:
    return result;
}
```

打开对应的时钟，添加 __HAL_RCC_TIMx_CLK_ENABLE();
就可以使用啦。

### rt_drv_pwm.c中存在书写错误，不过不影响使用

```
static int pwm_disable(int argc, char **argv)
{
    int result = 0;
    struct rt_device_pwm *device = RT_NULL;

if (argc != 3)
    {
        rt_kprintf("Usage: pwm_disable [device] [channel]\n");
        result = -RT_ERROR;
        goto _exit;
    }

device = (struct rt_device_pwm *)rt_device_find(argv[1]);
    if (!device)
    {
        rt_kprintf("ERROR: device %s can't be found!\n", argv[1]);
        result = -RT_EIO;
        goto _exit;
    }

result = rt_pwm_disable(device, atoi(argv[2]));

_exit:
    return result;
}
```