目录

一、IIC轮询模式

1.1 配置

 1.2 编写AHT20驱动

1.2.1  aht20.h

1.2.2 aht20.c

二、I2C中断

2.1 打开中断

 2.2 分离读取流程

2.3 在主函数中重新编写读取流程

2.4 在i2c.c中重新定义stm32f1xx_hal_i2c.h中的两个函数

三、I2CDMA

3.1 配置DMA通道

 3.2 代码的修改

---

一、IIC轮询模式

1.1 配置

 1.2 编写AHT20驱动

根据AHT20手册编写初始化与读数据函数

1.2.1  aht20.h

#ifndef INC_AHT20_H_
#define INC_AHT20_H_

#include "i2c.h"


void AHT20_Init();
void AHT20_Read(float* Temperature,float* Humidity);


#endif /* INC_AHT20_H_ */

1.2.2 aht20.c

#include "aht20.h"


#define AHT20_ADDRESS 0x70

void AHT20_Init()
{
	uint8_t readBuffer;
	HAL_Delay(40);
	HAL_I2C_Master_Receive(&hi2c1,AHT20_ADDRESS,&readBuffer,1,HAL_MAX_DELAY);
	if((readBuffer& 0x80)==0x00)
	{
		uint8_t sendBuffer[3]={0xBE,0x80,0x00};
		HAL_I2C_Master_Transmit(&hi2c1, AHT20_ADDRESS, sendBuffer, 3, HAL_MAX_DELAY);
	}
}


void AHT20_Read(float* Temperature,float* Humidity)
{
	uint8_t sendBuffer[3] = {0xAC,0x33,0x00};
	uint8_t readBuffer[6];

	HAL_I2C_Master_Transmit(&hi2c1, AHT20_ADDRESS, sendBuffer, 3, HAL_MAX_DELAY);
	HAL_Delay(75);
	HAL_I2C_Master_Receive(&hi2c1,AHT20_ADDRESS,readBuffer,6,HAL_MAX_DELAY);

	if((readBuffer[0] & 0x80)== 0x00)
	{
		uint32_t date = 0;
		date=(((uint32_t)readBuffer[3]>>4) + ((uint32_t)readBuffer[2]<<4) + ((uint32_t)readBuffer[1]<<12));
		*Humidity = date * 100.0f/(1<<20);

		date=(((uint32_t)readBuffer[3]&0x0F)<<16) + ((uint32_t)readBuffer[4]<<8) + (uint32_t)readBuffer[5];
		*Temperature = date * 200.0f/(1<<20)-50;
	}
}

二、I2C中断

2.1 打开中断

 2.2 分离读取流程

分为测量指令 读取指令 解析 三部分

void AHT20_Measure()
{
	static uint8_t sendBuffer[3] = {0xAC,0x33,0x00};
	HAL_I2C_Master_Transmit_IT(&hi2c1, AHT20_ADDRESS, sendBuffer, 3);
}

void AHT20_Get()
{
	HAL_I2C_Master_Receive_IT(&hi2c1,AHT20_ADDRESS,readBuffer,6);
}

void AHT20_Analysis(float* Temperature,float* Humidity)
{
	if((readBuffer[0] & 0x80)== 0x00)
	{
		uint32_t date = 0;
		date=(((uint32_t)readBuffer[3]>>4) + ((uint32_t)readBuffer[2]<<4) + ((uint32_t)readBuffer[1]<<12));
		*Humidity = date * 100.0f/(1<<20);

		date=(((uint32_t)readBuffer[3]&0x0F)<<16) + ((uint32_t)readBuffer[4]<<8) + (uint32_t)readBuffer[5];
		*Temperature = date * 200.0f/(1<<20)-50;
	}
}

2.3 在主函数中重新编写读取流程

	  if(aht20State==0)
	  {
		  AHT20_Measure();
		  aht20State=1;
	  }else if(aht20State==2)
	  {
		  HAL_Delay(75);
		  AHT20_Get();
		  aht20State=3;
	  }else if(aht20State==4)
	  {
		  AHT20_Analysis(&temperature, &humidity);
		  sprintf(message,"温度�? %.1f �?, 湿度�?%.1f %%\r\n",temperature,humidity);
		  HAL_UART_Transmit(&huart1, (uint8_t*)message, strlen(message), HAL_MAX_DELAY);

		  HAL_Delay(1000);
		  aht20State=0;
	  }

2.4 在i2c.c中重新定义stm32f1xx_hal_i2c.h中的两个函数

// 发送完成时回调
void HAL_I2C_MasterTxCpltCallback(I2C_HandleTypeDef *hi2c)
{
	if(hi2c==&hi2c1)
	{
		aht20State=2;
	}
}

void HAL_I2C_MasterRxCpltCallback(I2C_HandleTypeDef *hi2c)
{
	if(hi2c==&hi2c1)
	{
		aht20State=4;
	}
}

三、I2CDMA

3.1 配置DMA通道

 3.2 代码的修改

HAL_I2C_Master_Transmit_IT(&hi2c1, AHT20_ADDRESS, sendBuffer, 3);
//修改为
HAL_I2C_Master_Transmit_DMA(&hi2c1, AHT20_ADDRESS, sendBuffer, 3);

HAL_I2C_Master_Receive_IT(&hi2c1,AHT20_ADDRESS,readBuffer,6);
//修改为
HAL_I2C_Master_Receive_DMA(&hi2c1,AHT20_ADDRESS,readBuffer,6);