ADC采样只有0和3.3v?

发布于 2022-03-06 14:28:11 浏览：1329 订阅该版

N32G457 ADC采样只有3.3v 和0 这两个值
```c
#include <rtthread.h>
#include "board.h"
#include <rtdevice.h>
#include "protocol.h"

#define ADC_DEV_NAME        "adc2"      /* ADC 设备名称 */
#define ADC_DEV_CHANNEL      4
#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        4095   /* 转换位数为12位 */

static int adc_thread_entry(int argc, char *argv[])
{
    rt_adc_device_t adc_dev;
    rt_uint32_t value, vol;
    rt_err_t ret = RT_EOK;
    while(1){
    /* 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);

value = rt_adc_read(adc_dev, ADC_DEV_CHANNEL);
    rt_kprintf("the value is :%d \n", value);

/* 转换为对应电压值 */
    vol = value * REFER_VOLTAGE / CONVERT_BITS;
    rt_kprintf("the voltage is :%d.%02d \n", vol / 100, vol % 100);
    /*
    if(value<800)
        {
        mcu_dp_enum_update(DPID_COVER_STATE,0); //当前蜂箱盖状态枚举型数据上报;
        }
        else  {
        mcu_dp_enum_update(DPID_COVER_STATE,1); //当前蜂箱盖状态枚举型数据上报;
        }
        */

rt_thread_mdelay(500);

/* 关闭通道 */
    ret = rt_adc_disable(adc_dev, ADC_DEV_CHANNEL);
}
    return ret;
}

int rt_thread_adc(void)
{
    rt_thread_t ret=rt_thread_create("read_adc",adc_thread_entry,RT_NULL,512,10,10);

if(ret!=RT_NULL)
          {
              rt_kprintf("rt_thread_read_adc succeed....\n");
              rt_thread_startup(ret);
          }
          else {
           rt_kprintf("rt_thread_read_adc    err....\n");
          }

}

INIT_APP_EXPORT(rt_thread_adc);

/* 导出到 msh 命令列表中 */
//MSH_CMD_EXPORT(rt_thread_adc, adc7_thread_entry);

```