ADC
ADC介绍
ADC全称: Analog-to-Digital Converter,指模拟/数字转换器,是指将连续变化的模拟信号转换为 离散的数字信号。
ADC的性能指标
ADC的特性
ADC时钟
由时钟控制器提供的ADCCLK时钟和PCLK2(APB2时钟)同步。
ADC通道
ADC转换顺序
每个ADC只有一个数据寄存器,16个通道一起共用这个寄存器,所以需要指定规则转换通道的转换顺序。
规则通道
注入通道
ADC触发方式
ADC转换时间
ADC转化模式
单次转换/连续转换
扫描模式
模拟看门狗
当被ADC转换的模拟电压低于低阈值或者高于高阈值时,ADC的模拟看门狗状态位被设置,如果使能了AWDIE位将会产生中断。
使用ADC读取烟雾传感器(MQ-2)的值
STM32的hal库关于ADC的函数
HAL_ADC_Start()
启动某个ADC的转换。
原型:
HAL_StatusTypeDef HAL_ADC_Start(ADC_HandleTypeDef_ hadc)
参数:
ADC_HandleTypeDef_ hadc:ADC句柄
实例:
HAL_ADC_Start(&hadc1); //启动ADC1的转换
HAL_ADC_PollForConversion()
等待某个ADC转换完成。
原型:
HAL_StatusTypeDef HAL_ADC_PollForConversion(ADC_HandleTypeDef_ hadc, uint32_t Timeout)
参数:
ADC_HandleTypeDef_ hadc:ADC句柄
uint32_t Timeout:超时时间
实例:
HAL_ADC_PollForConversion(&hadc1,100); //等待ADC1的转换完成,只等待100ms
HAL_ADC_GetValue()
读取某个ADC转换完成的数据。
原型:
uint32_t HAL_ADC_GetValue(ADC_HandleTypeDef_ hadc)
参数:
ADC_HandleTypeDef_ hadc:ADC句柄
实例:
uint32_t smoke_value = 0;
smoke_value = HAL_ADC_GetValue(&hadc1); //读取ADC1转换完成的数据到smoke_value
烟雾传感器(MQ-2)与STM32F103C8T6板子接线
在STM32F103C8T6的产品手册中找到板子上的ADC1通道0的接口。
STM32CubeMX相关配置
配置SYS
配置RCC
ADC是挂载在APB2总线(PCLK2) 上的,经过分频器得到ADC时钟(ADCCLK),最高14MHz。
配置串口信息(UART1)
配置ADC
配置工程名称、工程路径
选择固件库
生成工程
使用MicroLIB库
main.c文件编写
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* Copyright (c) 2023 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "adc.h"
#include "usart.h"
#include "gpio.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include <stdio.h>
/* USER CODE END Includes */
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
/* USER CODE END PTD */
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
/* USER CODE END PM */
/* Private variables ---------------------------------------------------------*/
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
//重写stdio.h文件中的prinft()里的fputc()函数
int fputc(int my_data,FILE *p)
{
unsigned char temp = my_data;
//改写后,使用printf()函数会将数据通过串口一发送出去
HAL_UART_Transmit(&huart1,&temp,1,0xffff); //0xfffff为最大超时时间
return my_data;
}
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
int main(void)
{
/* USER CODE BEGIN 1 */
uint32_t smoke_value = 0;
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_ADC1_Init();
MX_USART1_UART_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
//1. 启动ADC1的转换
HAL_ADC_Start(&hadc1);
//2. 等待ADC1转换的完成,超时时间为100ms
HAL_ADC_PollForConversion(&hadc1,100);
//3. 读取ADC1转换完成的数据到smoke_value
smoke_value = HAL_ADC_GetValue(&hadc1);
//4. 将数据打印到串口
//printf("smokeValue = %d\r\n",smoke_value);
printf("smokeValue = %f\r\n",3.3/4096*smoke_value);
HAL_Delay(1000);
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{
Error_Handler();
}
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_ADC;
PeriphClkInit.AdcClockSelection = RCC_ADCPCLK2_DIV6;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
{
Error_Handler();
}
}
/* USER CODE BEGIN 4 */
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
__disable_irq();
while (1)
{
}
/* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t *file, uint32_t line)
{
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
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