RT-Thread-【实验2：ADC电位计实验】RT-Thread问答社区

【实验2：ADC电位计实验】

发布于 2022-08-18 10:40:22 浏览：508 订阅该版

[tocm]

# 1. 前言
本实验使用了板载电位计（USER POT）通过ADC外设通道读取电平值，可以手动调节电位计查看ADC
通道的电平变化。通过本实验可以学习到简单外设的配置，包括rt-thread的外设配置和FSP的外设配
置。

# 2. 查看开发板用户手册
查看手册提取出需要注意的关键信息，电位计使用的ADC引脚是 P004，同时需要短接E31（开发板背
面）才能连接到MCU。

![在这里插入图片描述](https://oss-club.rt-thread.org/uploads/20220818/4c6bd1d2ba2c4cdada65896a1204bc3b21e6ad12.png)

# 3. FSP配置ADC
打开FSP，在Pins页找到 P004 引脚，并查看所属的ADC通道为ADC0通道

![在这里插入图片描述](https://oss-club.rt-thread.org/uploads/20220818/65252331665b246abd650a3a520958a186ba82b1.png)
- 在Stacks中添加ADC外设，配置ADC0，在Input配置中打开通道4的输入功能

![在这里插入图片描述](https://oss-club.rt-thread.org/uploads/20220818/b5fc8415fb3c4a9e05c622109621e32fe7961a76.png)
- 配置完成点击生成代码，此步必须操作否则配置不会添加到工程中。

![在这里插入图片描述](https://oss-club.rt-thread.org/uploads/20220818/3af09d2079fd718bf9a20fbb24e952a6880bb7d5.png)
# 4. 打开ADC设备驱动
在 RT-Thread settings 中打开 ADC0，保存配置。

![在这里插入图片描述](https://oss-club.rt-thread.org/uploads/20220818/d9b93cf718ed1bd4a714b33b12e0bd36eb64f21c.png)
# 5. 测试验证
添加测试代码到 `hal_entry.c`

```cpp
#define ADC_DEV_NAME "adc0"
#define ADC_DEV_CHANNEL 4
#define REFER_VOLTAGE 330
#define CONVERT_BITS (1 << 12)
static void sensor_read_data(void)
{
rt_adc_device_t adc_dev;
rt_uint32_t value, vol;
rt_err_t ret = RT_EOK;
adc_dev = (rt_adc_device_t)rt_device_find(ADC_DEV_NAME);
if (adc_dev == RT_NULL)
编译下载，输入测试命令 sensor_read_data 查看电位计此时的电平值，可以使用工具旋转电位
计，查看电平变化。
{
rt_kprintf("adc sample run failed! can't find %s device!\n",
ADC_DEV_NAME);
return RT_ERROR;
}
ret = rt_adc_enable(adc_dev, ADC_DEV_CHANNEL);
value = rt_adc_read(adc_dev, ADC_DEV_CHANNEL);
ret = rt_adc_disable(adc_dev, ADC_DEV_CHANNEL);
vol = value * REFER_VOLTAGE / CONVERT_BITS;
rt_kprintf("the voltage is :%d.%02d \n", vol / 100, vol % 100);
}
MSH_CMD_EXPORT(sensor_read_data, sensor_read_data);
```

**`hal_entry.c`完整代码**
```cpp
/*
 * Copyright (c) 2006-2021, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author        Notes
 * 2021-10-10     Sherman       first version
 * 2021-11-03     Sherman       Add icu_sample
 */

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

#define LED3_PIN    BSP_IO_PORT_01_PIN_06
#define USER_INPUT  "P105"

void hal_entry(void)
{
    rt_kprintf("\nHello RT-Thread!\n");

while (1)
    {
        rt_pin_write(LED3_PIN, PIN_HIGH);
        rt_thread_mdelay(500);
        rt_pin_write(LED3_PIN, PIN_LOW);
        rt_thread_mdelay(500);
    }
}

void irq_callback_test(void *args)
{
    rt_kprintf("\n IRQ00 triggered \n");
}

void icu_sample(void)
{
    /* init */
    rt_uint32_t pin = rt_pin_get(USER_INPUT);
    rt_kprintf("\n pin number : 0x%04X \n", pin);
    rt_err_t err = rt_pin_attach_irq(pin, PIN_IRQ_MODE_RISING, irq_callback_test, RT_NULL);
    if(RT_EOK != err)
    {
        rt_kprintf("\n attach irq failed. \n");
    }
    err = rt_pin_irq_enable(pin, PIN_IRQ_ENABLE);
    if(RT_EOK != err)
    {
        rt_kprintf("\n enable irq failed. \n");
    }
}
MSH_CMD_EXPORT(icu_sample, icu sample);

#define ADC_DEV_NAME "adc0"
#define ADC_DEV_CHANNEL 4
#define REFER_VOLTAGE 330
#define CONVERT_BITS (1 << 12)
static void sensor_read_data(void)
{
    rt_adc_device_t adc_dev;
    rt_uint32_t value, vol;
    rt_err_t ret = RT_EOK;
    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;
    }
    ret = rt_adc_enable(adc_dev, ADC_DEV_CHANNEL);
    value = rt_adc_read(adc_dev, ADC_DEV_CHANNEL);
    ret = rt_adc_disable(adc_dev, ADC_DEV_CHANNEL);
    vol = value * REFER_VOLTAGE / CONVERT_BITS;
    rt_kprintf("the voltage is :%d.%02d \n", vol / 100, vol % 100);
}
MSH_CMD_EXPORT(sensor_read_data, sensor_read_data);

```

编译下载，输入测试命令 'sensor_read_data' 查看电位计此时的电平值，可以使用工具旋转电位
计，查看电平变化。

```bash
C:\Users\Asus>D:/RT-ThreadStudio/plugins/org.rt-thread.studio.serial.putty_1.0.5/putty/plink.exe -serial COM8 -sercfg 115200,8,n,1,N

\ | /
- RT -     Thread Operating System
 / | \     4.1.0 build Aug 15 2022 16:44:58
 2006 - 2022 Copyright by RT-Thread team

Hello RT-Thread!
msh >sensor_read_data
the voltage is :1.73
msh >sensor_read_data
the voltage is :1.73
msh >sensor_read_data
the voltage is :1.97
msh >sensor_read_data
the voltage is :0.00
msh >sensor_read_data
the voltage is :0.00
msh >sensor_read_data
the voltage is :3.04
msh >
```

参考文献：
- [【实验1：RT-Thread环境搭建+IIC光线传感器实验】](https://blog.csdn.net/VOR234/article/details/126347128)
- [【实验2：ADC电位计实验】](https://blog.csdn.net/VOR234/article/details/126349596)
- [【实验3：RW007联网实验】](https://blog.csdn.net/VOR234/article/details/126350283)
- [【实验4：MQTT交互实验】](https://blog.csdn.net/VOR234/article/details/126350769)
- [【实验5：网关上云实验】](https://blog.csdn.net/VOR234/article/details/126350972)
- [demo文件](https://download.csdn.net/download/VOR234/86401651)