RT-Thread-RT-Thread开发GD32F450 添加adc外设RT-Thread问答社区

RT-Thread开发GD32F450 添加adc外设

发布于 2023-03-21 10:24:09 浏览：910 订阅该版

开发板使用的是gd32f450zk，env工具使用的版本是1.3.5，rtthread版本是5.0.0
  添加adc外设的步骤如下：
  步骤1： 查看开发板的电路原理图，确定adc的使用引脚，使用的是引脚PF6，即adc012_IN4，如下图：
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230321/addafb6a9c14bcece425ed3ad132ab1b.png)
  步骤2： 使用env工具开启adc外设，并选择配置相应的adc外设，如下如
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230321/3165517e8148cebd0e3bb7608620dc57.png)
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230321/3d275bd984e87934f7633a52a8d6e053.png)
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230321/ce82ac543dd5a3c06cd1106e649047ec.png)
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230321/683a5b2e840cb8b57d1e4575bbe31817.png)
  步骤3：打开drv_adc.c文件，修改代码
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230321/08873665474e6f3798baa938d9bf311b.png.webp)
  修改后代码如下，也可以全部修改为GET_PIN(F, 6)
```
#ifdef BSP_USING_ADC2
    {
        ADC2,
        RCU_ADC2,
        {
            GET_PIN(A, 0), GET_PIN(A, 1), GET_PIN(A, 2), GET_PIN(A, 3),
            GET_PIN(F, 6), GET_PIN(A, 5), GET_PIN(A, 6), GET_PIN(A, 7),
            GET_PIN(B, 0), GET_PIN(B, 1), GET_PIN(C, 0), GET_PIN(C, 1),
            GET_PIN(C, 2), GET_PIN(C, 3), GET_PIN(C, 4), GET_PIN(C, 5),
        },
        &adc2,
        "adc2",
    },
#endif
```
  还需要修改的函数有：
```
static rt_err_t gd32_adc_enabled(struct rt_adc_device *device, rt_uint32_t channel, rt_bool_t enabled);
static rt_err_t gd32_adc_convert(struct rt_adc_device *device, rt_uint32_t channel, rt_uint32_t *value);
```
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230321/620359958ecd4a4e39d3d7d439205791.png.webp)提示**ADC_REGULAR_CHANNEL** 未定义。改为**ADC_ROUTINE_CHANNEL**，同时将其余报错进行修改，修改后的代码如下：
```
/**
* @brief ADC enable
*        This function enable adc.
* @param device, channel, enabled
* @retval None
*/
static rt_err_t gd32_adc_enabled(struct rt_adc_device *device, rt_uint32_t channel, rt_bool_t enabled)
{
    uint32_t adc_periph;
    struct gd32_adc * adc = (struct gd32_adc *)device->parent.user_data;

if (channel >= MAX_EXTERN_ADC_CHANNEL)
    {
        LOG_E("invalid channel");
        return -RT_EINVAL;
    }

adc_periph = (uint32_t )(adc->adc_periph);

if (enabled == ENABLE)
    {
        gd32_adc_gpio_init(adc->adc_clk, adc->adc_pins[channel]);

adc_channel_length_config(adc_periph, ADC_ROUTINE_CHANNEL, 1);
        adc_data_alignment_config(adc_periph, ADC_DATAALIGN_RIGHT);

#if defined SOC_SERIES_GD32F4xx
        adc_external_trigger_source_config(adc_periph, ADC_ROUTINE_CHANNEL, ADC_EXTTRIG_ROUTINE_EXTI_11);
#else
        adc_external_trigger_source_config(adc_periph, ADC_REGULAR_CHANNEL, ADC0_1_2_EXTTRIG_REGULAR_NONE);
#endif
        adc_external_trigger_config(adc_periph, ADC_ROUTINE_CHANNEL, ENABLE);

#if defined SOC_SERIES_GD32F4xx
        adc_routine_channel_config(adc_periph, 0, channel, ADC_SAMPLETIME_480);
#else
        adc_regular_channel_config(adc_periph, 0, channel, ADC_SAMPLETIME_13POINT5);
#endif

adc_enable(adc_periph);

/* ADC calibration and reset calibration */
        adc_calibration_enable(adc_periph);
    }
    else
    {
        adc_disable(adc_periph);
    }
    return 0;
}

/**
* @brief convert adc.
*        This function get adc value.
* @param device, channel, value
* @retval None
*/
static rt_err_t gd32_adc_convert(struct rt_adc_device *device, rt_uint32_t channel, rt_uint32_t *value)
{
    uint32_t adc_periph;
    struct gd32_adc * adc = (struct gd32_adc *)(device->parent.user_data);

if (!value)
    {
        LOG_E("invalid param");
        return -RT_EINVAL;
    }

adc_periph = (uint32_t )(adc->adc_periph);
    adc_software_trigger_enable(adc_periph, ADC_ROUTINE_CHANNEL);

while(!adc_flag_get(adc_periph, ADC_FLAG_EOC)){};
    // clear flag
    adc_flag_clear(adc_periph, ADC_FLAG_EOC);

*value = adc_routine_data_read(adc_periph);

return 0;
}
```
  步骤4：编译正常，下载到开发板，进行测试，测试指令如下：
```
msh />adc
Usage: 
adc probe <device name> - probe adc by name
adc read <channel>      - read adc value on the channel
adc disable <channel>   - disable adc channel
adc enable <channel>    - enable adc channel
```
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230321/0a62d18fdd483c90ad39ffbb11185b81.png.webp)
步骤5：测试发现输入并无变化的情况下，读取的值一直在变，并且变化太大，读取到的值快速减小。说明配置的有问题，查找原因，发现再使能adc外设的时候，没有对引脚的时钟进行使能，再**static void gd32_adc_gpio_init(rcu_periph_enum adc_clk, rt_base_t pin)函数中**增加使能引脚时钟，修改如下：
```
rcu_periph_clock_enable(RCU_GPIOF);
```
  修改之后测试，测试结果
![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230321/14bc337c1dbb200940469c3d8f61c81b.png.webp)，读取的值不会变化很大，而是再一定的范围内变化。
c文件
[drv_adc.7z](https://club.rt-thread.org/file_download/c9367ba969f7520f)