rtt优先级设置的问题

```
#define ADC_DEV_NAME "adc0" /* ADC 设备名称 */
#define ADC_DEV_CHANNEL  9 /* ADC 通道 */
#define REFER_VOLTAGE    330 /* 参考电压 3.3V,数据精度乘以 100 保留 2 位小数*/
#define CONVERT_BITS     1024 /* 转换位数为 10 位 */
```
```
void adc_init()
{
//    adc = rt_pin_get("PE.7");
//    rt_pin_mode(adc, PIN_MODE_INPUT);

//    rt_adc_device_t adc_dev;
    rt_err_t ret = RT_EOK;
    /* 查找设备 */
    adc_dev = (rt_adc_device_t)rt_device_find(ADC_DEV_NAME);
    if (adc_dev == RT_NULL)
    {
    rt_kprintf("adc sample run failed! can't find %s device!\n", ADC_DEV_NAME);
//    return RT_ERROR;
    }
    /* 使能设备 */
    ret = rt_adc_enable(adc_dev, ADC_DEV_CHANNEL);

}
```
```
void adc_read()
{
    uint32_t value, vol,v;
    /* 读取采样值 */
    buffad[0] = rt_adc_read(adc_dev, ADC_DEV_CHANNEL);
    rt_kprintf("the value is :%d \n", value);
    /* 转换为对应电压值 */
    value = buffad[0];
    value = value + buffad[0];
    value = value + buffad[0];
    value = value + buffad[0];
    value = value / 4;

vol = value * REFER_VOLTAGE / CONVERT_BITS;
    buffad[1]= vol*2;

buffad[2]=((buffad[1]-275)/145)*100;
    v = buffad[2];
    rt_kprintf("the voltage is :%d.%02d \n",v / 100 ,v % 100);

}
```
```
static void adc_thread_entry(void* p)
{
    adc_init();
    while(1)
    {
        rt_kprintf("Thread_ADC");
        adc_read();
        rt_thread_mdelay(5000);
    }
}
```