1.“软件I2C”和“硬件I2C”

所谓硬件I2C对应芯片上的I2C外设，有相应I2C驱动电路，其所使用的I2C管脚bai也是专用的；软件I2C一般是用GPIO管脚，用软件控制管脚状态以模拟I2C通信波形。
硬件I2C的效率要远高于软件的，而软件I2C由于不受管脚限制，接口比较灵活。
本次实验中使用的软件I2C

2.stm32f103指南者外接AHT20进行温度采集。

连接硬件

AHT20的SCL，GND，SDA，VCC分别对应接stm32f103指南者i2c模块的B6，GND，B7，5V。（GND和5V任意模块都可以）

代码实现

此处在固件库版的空白工程上进行添加代码，并实现以下功能：
每隔2秒钟采集一次温湿度数据，并通过串口发送到上位机

首先主函数如下：
main.c

#include "delay.h"
#include "usart.h"
#include "bsp_i2c.h"int main(void)
{	delay_init();     //ÑÓÊ±º¯Êý³õÊ¼»¯	  uart_init(115200);	 //´®¿Ú³õÊ¼»¯Îª115200IIC_Init();while(1){printf("¿ªÊ¼²âÁ¿£¬ÇëÉÔµÈ£º");read_AHT20_once();delay_ms(1500);}
}

然后把以下代码文件和main.c放到一起
usart.c

#include "sys.h"
#include "usart.h"//STM32F103ºËÐÄ°åÀý³Ì
//¿âº¯Êý°æ±¾Àý³Ì
/********** mcudev.taobao.com ³öÆ·  ********/// 	 
//Èç¹ûÊ¹ÓÃucos,Ôò°üÀ¨ÏÂÃæµÄÍ·ÎÄ¼þ¼´¿É.
#if SYSTEM_SUPPORT_UCOS
#include "includes.h"					//ucos Ê¹ÓÃ	  
#endif
//	 
//STM32¿ª·¢°å
//´®¿Ú1³õÊ¼»¯		   // 	  //
//¼ÓÈëÒÔÏÂ´úÂë,Ö§³Öprintfº¯Êý,¶ø²»ÐèÒªÑ¡Ôñuse MicroLIB	  
#if 1
#pragma import(__use_no_semihosting)             
//±ê×¼¿âÐèÒªµÄÖ§³Öº¯Êý                 
struct __FILE 
{ int handle; }; FILE __stdout;       
//¶¨Òå_sys_exit()ÒÔ±ÜÃâÊ¹ÓÃ°ëÖ÷»úÄ£Ê½    
void _sys_exit(int x) 
{ x = x; 
} 
//ÖØ¶¨Òåfputcº¯Êý 
int fputc(int ch, FILE *f)
{      while((USART1->SR&0X40)==0);//Ñ»··¢ËÍ,Ö±µ½·¢ËÍÍê±Ï   USART1->DR = (u8) ch;      return ch;
}
#endif /*Ê¹ÓÃmicroLibµÄ·½·¨*//* 
int fputc(int ch, FILE *f)
{USART_SendData(USART1, (uint8_t) ch);while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET) {}	return ch;
}
int GetKey (void)  { while (!(USART1->SR & USART_FLAG_RXNE));return ((int)(USART1->DR & 0x1FF));
}
*/#if EN_USART1_RX   //Èç¹ûÊ¹ÄÜÁË½ÓÊÕ
//´®¿Ú1ÖÐ¶Ï·þÎñ³ÌÐò
//×¢Òâ,¶ÁÈ¡USARTx->SRÄÜ±ÜÃâÄªÃûÆäÃîµÄ´íÎó   	
u8 USART_RX_BUF[USART_REC_LEN];     //½ÓÊÕ»º³å,×î´óUSART_REC_LEN¸ö×Ö½Ú.
//½ÓÊÕ×´Ì¬
//bit15£¬	½ÓÊÕÍê³É±êÖ¾
//bit14£¬	½ÓÊÕµ½0x0d
//bit13~0£¬	½ÓÊÕµ½µÄÓÐÐ§×Ö½ÚÊýÄ¿
u16 USART_RX_STA=0;       //½ÓÊÕ×´Ì¬±ê¼Ç	  void uart_init(u32 bound){//GPIO¶Ë¿ÚÉèÖÃGPIO_InitTypeDef GPIO_InitStructure;USART_InitTypeDef USART_InitStructure;NVIC_InitTypeDef NVIC_InitStructure;RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA, ENABLE);	//Ê¹ÄÜUSART1£¬GPIOAÊ±ÖÓ//USART1_TX   PA.9GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; //PA.9GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;	//¸´ÓÃÍÆÍìÊä³öGPIO_Init(GPIOA, &GPIO_InitStructure);//USART1_RX	  PA.10GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//¸¡¿ÕÊäÈëGPIO_Init(GPIOA, &GPIO_InitStructure);  //Usart1 NVIC ÅäÖÃNVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;//ÇÀÕ¼ÓÅÏÈ¼¶3NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;		//×ÓÓÅÏÈ¼¶3NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;			//IRQÍ¨µÀÊ¹ÄÜNVIC_Init(&NVIC_InitStructure);	//¸ù¾ÝÖ¸¶¨µÄ²ÎÊý³õÊ¼»¯VIC¼Ä´æÆ÷//USART ³õÊ¼»¯ÉèÖÃUSART_InitStructure.USART_BaudRate = bound;//Ò»°ãÉèÖÃÎª9600;USART_InitStructure.USART_WordLength = USART_WordLength_8b;//×Ö³¤Îª8Î»Êý¾Ý¸ñÊ½USART_InitStructure.USART_StopBits = USART_StopBits_1;//Ò»¸öÍ£Ö¹Î»USART_InitStructure.USART_Parity = USART_Parity_No;//ÎÞÆæÅ¼Ð£ÑéÎ»USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//ÎÞÓ²¼þÊý¾ÝÁ÷¿ØÖÆUSART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;	//ÊÕ·¢Ä£Ê½USART_Init(USART1, &USART_InitStructure); //³õÊ¼»¯´®¿ÚUSART_ITConfig(USART1, USART_IT_RXNE, ENABLE);//¿ªÆôÖÐ¶ÏUSART_Cmd(USART1, ENABLE);                    //Ê¹ÄÜ´®¿Ú }void USART1_IRQHandler(void)                	//´®¿Ú1ÖÐ¶Ï·þÎñ³ÌÐò{u8 Res;
#ifdef OS_TICKS_PER_SEC	 	//Èç¹ûÊ±ÖÓ½ÚÅÄÊý¶¨ÒåÁË,ËµÃ÷ÒªÊ¹ÓÃucosIIÁË.OSIntEnter();    
#endifif(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)  //½ÓÊÕÖÐ¶Ï(½ÓÊÕµ½µÄÊý¾Ý±ØÐëÊÇ0x0d 0x0a½áÎ²){Res =USART_ReceiveData(USART1);//(USART1->DR);	//¶ÁÈ¡½ÓÊÕµ½µÄÊý¾Ýif((USART_RX_STA&0x8000)==0)//½ÓÊÕÎ´Íê³É{if(USART_RX_STA&0x4000)//½ÓÊÕµ½ÁË0x0d{if(Res!=0x0a)USART_RX_STA=0;//½ÓÊÕ´íÎó,ÖØÐÂ¿ªÊ¼else USART_RX_STA|=0x8000;	//½ÓÊÕÍê³ÉÁË }else //»¹Ã»ÊÕµ½0X0D{	if(Res==0x0d)USART_RX_STA|=0x4000;else{USART_RX_BUF[USART_RX_STA&0X3FFF]=Res ;USART_RX_STA++;if(USART_RX_STA>(USART_REC_LEN-1))USART_RX_STA=0;//½ÓÊÕÊý¾Ý´íÎó,ÖØÐÂ¿ªÊ¼½ÓÊÕ	  }		 }}   		 } 
#ifdef OS_TICKS_PER_SEC	 	//Èç¹ûÊ±ÖÓ½ÚÅÄÊý¶¨ÒåÁË,ËµÃ÷ÒªÊ¹ÓÃucosIIÁË.OSIntExit();  											 
#endif
} 
#endif

usart.h

#ifndef __USART_H
#define __USART_H
#include "stdio.h"	
#include "sys.h" //STM32F103ºËÐÄ°åÀý³Ì
//¿âº¯Êý°æ±¾Àý³Ì
/********** mcudev.taobao.com ³öÆ·  ********///	 
//STM32¿ª·¢°å
//´®¿Ú1³õÊ¼»¯		   #define USART_REC_LEN  			200  	//¶¨Òå×î´ó½ÓÊÕ×Ö½ÚÊý 200
#define EN_USART1_RX 			1		    //Ê¹ÄÜ£¨1£©/½ûÖ¹£¨0£©´®¿Ú1½ÓÊÕextern u8  USART_RX_BUF[USART_REC_LEN]; //½ÓÊÕ»º³å,×î´óUSART_REC_LEN¸ö×Ö½Ú.Ä©×Ö½ÚÎª»»ÐÐ·û 
extern u16 USART_RX_STA;         		//½ÓÊÕ×´Ì¬±ê¼Ç	
//Èç¹ûÏë´®¿ÚÖÐ¶Ï½ÓÊÕ£¬Çë²»Òª×¢ÊÍÒÔÏÂºê¶¨Òå
void uart_init(u32 bound);
#endif

bsp_i2c.c

#include "bsp_i2c.h"
#include "delay.h"uint8_t   ack_status=0;
uint8_t   readByte[6];
uint8_t   AHT20_status=0;uint32_t  H1=0;  //Humility
uint32_t  T1=0;  //Temperatureuint8_t  AHT20_OutData[4];
uint8_t  AHT20sendOutData[10] = {0xFA, 0x06, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF};void IIC_Init(void)
{					     GPIO_InitTypeDef GPIO_InitStructure;RCC_APB2PeriphClockCmd(	RCC_APB2Periph_GPIOB, ENABLE );	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6|GPIO_Pin_7;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP ;   //ÍÆÍìÊä³öGPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOB, &GPIO_InitStructure);IIC_SCL=1;IIC_SDA=1;}
//²úÉúIICÆðÊ¼ÐÅºÅ
void IIC_Start(void)
{SDA_OUT();     //sdaÏßÊä³öIIC_SDA=1;	  	  IIC_SCL=1;delay_us(4);IIC_SDA=0;//START:when CLK is high,DATA change form high to low delay_us(4);IIC_SCL=0;//Ç¯×¡I2C×ÜÏß£¬×¼±¸·¢ËÍ»ò½ÓÊÕÊý¾Ý 
}	  
//²úÉúIICÍ£Ö¹ÐÅºÅ
void IIC_Stop(void)
{SDA_OUT();//sdaÏßÊä³öIIC_SCL=0;IIC_SDA=0;//STOP:when CLK is high DATA change form low to highdelay_us(4);IIC_SCL=1; IIC_SDA=1;//·¢ËÍI2C×ÜÏß½áÊøÐÅºÅdelay_us(4);							   	
}
//µÈ´ýÓ¦´ðÐÅºÅµ½À´
//·µ»ØÖµ£º1£¬½ÓÊÕÓ¦´ðÊ§°Ü
//        0£¬½ÓÊÕÓ¦´ð³É¹¦
u8 IIC_Wait_Ack(void)
{u8 ucErrTime=0;SDA_IN();      //SDAÉèÖÃÎªÊäÈë  IIC_SDA=1;delay_us(1);	   IIC_SCL=1;delay_us(1);	 while(READ_SDA){ucErrTime++;if(ucErrTime>250){IIC_Stop();return 1;}}IIC_SCL=0;//Ê±ÖÓÊä³ö0 	   return 0;  
} 
//²úÉúACKÓ¦´ð
void IIC_Ack(void)
{IIC_SCL=0;SDA_OUT();IIC_SDA=0;delay_us(2);IIC_SCL=1;delay_us(2);IIC_SCL=0;
}
//²»²úÉúACKÓ¦´ð		    
void IIC_NAck(void)
{IIC_SCL=0;SDA_OUT();IIC_SDA=1;delay_us(2);IIC_SCL=1;delay_us(2);IIC_SCL=0;
}					 				     
//IIC·¢ËÍÒ»¸ö×Ö½Ú
//·µ»Ø´Ó»úÓÐÎÞÓ¦´ð
//1£¬ÓÐÓ¦´ð
//0£¬ÎÞÓ¦´ð			  
void IIC_Send_Byte(u8 txd)
{                        u8 t;   SDA_OUT(); 	    IIC_SCL=0;//ÀµÍÊ±ÖÓ¿ªÊ¼Êý¾Ý´«Êäfor(t=0;t<8;t++){              IIC_SDA=(txd&0x80)>>7;txd<<=1; 	  delay_us(2);   //¶ÔTEA5767ÕâÈý¸öÑÓÊ±¶¼ÊÇ±ØÐëµÄIIC_SCL=1;delay_us(2); IIC_SCL=0;	delay_us(2);}	 
} 	    
//¶Á1¸ö×Ö½Ú£¬ack=1Ê±£¬·¢ËÍACK£¬ack=0£¬·¢ËÍnACK   
u8 IIC_Read_Byte(unsigned char ack)
{unsigned char i,receive=0;SDA_IN();//SDAÉèÖÃÎªÊäÈëfor(i=0;i<8;i++ ){IIC_SCL=0; delay_us(2);IIC_SCL=1;receive<<=1;if(READ_SDA)receive++;   delay_us(1); }					 if (!ack)IIC_NAck();//·¢ËÍnACKelseIIC_Ack(); //·¢ËÍACK   return receive;
}void IIC_WriteByte(uint16_t addr,uint8_t data,uint8_t device_addr)
{IIC_Start();  if(device_addr==0xA0) //eepromµØÖ·´óÓÚ1×Ö½ÚIIC_Send_Byte(0xA0 + ((addr/256)<<1));//·¢ËÍ¸ßµØÖ·elseIIC_Send_Byte(device_addr);	    //·¢Æ÷¼þµØÖ·IIC_Wait_Ack(); IIC_Send_Byte(addr&0xFF);   //·¢ËÍµÍµØÖ·IIC_Wait_Ack(); IIC_Send_Byte(data);     //·¢ËÍ×Ö½Ú							   IIC_Wait_Ack();  		    	   IIC_Stop();//²úÉúÒ»¸öÍ£Ö¹Ìõ¼þ if(device_addr==0xA0) //delay_ms(10);elsedelay_us(2);
}uint16_t IIC_ReadByte(uint16_t addr,uint8_t device_addr,uint8_t ByteNumToRead)  //¶Á¼Ä´æÆ÷»ò¶ÁÊý¾Ý
{	uint16_t data;IIC_Start();  if(device_addr==0xA0)IIC_Send_Byte(0xA0 + ((addr/256)<<1));elseIIC_Send_Byte(device_addr);	IIC_Wait_Ack();IIC_Send_Byte(addr&0xFF);   //·¢ËÍµÍµØÖ·IIC_Wait_Ack(); IIC_Start();  	IIC_Send_Byte(device_addr+1);	    //·¢Æ÷¼þµØÖ·IIC_Wait_Ack();if(ByteNumToRead == 1)//LM75ÎÂ¶ÈÊý¾ÝÎª11bit{data=IIC_Read_Byte(0);}else{data=IIC_Read_Byte(1);data=(data<<8)+IIC_Read_Byte(0);}IIC_Stop();//²úÉúÒ»¸öÍ£Ö¹Ìõ¼þ	    return data;
}/**********
*ÉÏÃæ²¿·ÖÎªIO¿ÚÄ£¿éI2CÅäÖÃ
*
*´ÓÕâÒÔÏÂ¿ªÊ¼ÎªAHT20µÄÅäÖÃI2C
*º¯ÊýÃûÓÐIICºÍI2CµÄÇø±ð£¬Çë×¢Òâ£¡£¡£¡£¡£¡
*
*2020/2/23×îºóÐÞ¸ÄÈÕÆÚ
*
***********/
void  read_AHT20_once(void)
{delay_ms(10);reset_AHT20();delay_ms(10);init_AHT20();delay_ms(10);startMeasure_AHT20();delay_ms(80);read_AHT20();delay_ms(5);
}void  reset_AHT20(void)
{I2C_Start();I2C_WriteByte(0x70);ack_status = Receive_ACK();if(ack_status) printf("1");else printf("1-n-");I2C_WriteByte(0xBA);ack_status = Receive_ACK();if(ack_status) printf("2");else printf("2-n-");I2C_Stop();/*AHT20_OutData[0] = 0;AHT20_OutData[1] = 0;AHT20_OutData[2] = 0;AHT20_OutData[3] = 0;*/
}void  init_AHT20(void)
{I2C_Start();I2C_WriteByte(0x70);ack_status = Receive_ACK();if(ack_status) printf("3");else printf("3-n-");	I2C_WriteByte(0xE1);ack_status = Receive_ACK();if(ack_status) printf("4");else printf("4-n-");I2C_WriteByte(0x08);ack_status = Receive_ACK();if(ack_status) printf("5");else printf("5-n-");I2C_WriteByte(0x00);ack_status = Receive_ACK();if(ack_status) printf("6");else printf("6-n-");I2C_Stop();
}void  startMeasure_AHT20(void)
{//------------I2C_Start();I2C_WriteByte(0x70);ack_status = Receive_ACK();if(ack_status) printf("7");else printf("7-n-");I2C_WriteByte(0xAC);ack_status = Receive_ACK();if(ack_status) printf("8");else printf("8-n-");I2C_WriteByte(0x33);ack_status = Receive_ACK();if(ack_status) printf("9");else printf("9-n-");I2C_WriteByte(0x00);ack_status = Receive_ACK();if(ack_status) printf("10");else printf("10-n-");I2C_Stop();
}void read_AHT20(void)
{uint8_t   i;for(i=0; i<6; i++){readByte[i]=0;}//-------------I2C_Start();I2C_WriteByte(0x71);ack_status = Receive_ACK();readByte[0]= I2C_ReadByte();Send_ACK();readByte[1]= I2C_ReadByte();Send_ACK();readByte[2]= I2C_ReadByte();Send_ACK();readByte[3]= I2C_ReadByte();Send_ACK();readByte[4]= I2C_ReadByte();Send_ACK();readByte[5]= I2C_ReadByte();SendNot_Ack();//Send_ACK();I2C_Stop();//--------------if( (readByte[0] & 0x68) == 0x08 ){H1 = readByte[1];H1 = (H1<<8) | readByte[2];H1 = (H1<<8) | readByte[3];H1 = H1>>4;H1 = (H1*1000)/1024/1024;T1 = readByte[3];T1 = T1 & 0x0000000F;T1 = (T1<<8) | readByte[4];T1 = (T1<<8) | readByte[5];T1 = (T1*2000)/1024/1024 - 500;AHT20_OutData[0] = (H1>>8) & 0x000000FF;AHT20_OutData[1] = H1 & 0x000000FF;AHT20_OutData[2] = (T1>>8) & 0x000000FF;AHT20_OutData[3] = T1 & 0x000000FF;}else{AHT20_OutData[0] = 0xFF;AHT20_OutData[1] = 0xFF;AHT20_OutData[2] = 0xFF;AHT20_OutData[3] = 0xFF;printf("Ê§°ÜÁË");}printf("\r\n");printf("ÎÂ¶È:%d%d.%d",T1/100,(T1/10)%10,T1%10);printf("Êª¶È:%d%d.%d",H1/100,(H1/10)%10,H1%10);printf("\r\n");
}uint8_t  Receive_ACK(void)
{uint8_t result=0;uint8_t cnt=0;IIC_SCL = 0;SDA_IN(); delay_us(4);IIC_SCL = 1;delay_us(4);while(READ_SDA && (cnt<100)){cnt++;}IIC_SCL = 0;delay_us(4);if(cnt<100){result=1;}return result;
}void  Send_ACK(void)
{SDA_OUT();IIC_SCL = 0;delay_us(4);IIC_SDA = 0;delay_us(4);IIC_SCL = 1;delay_us(4);IIC_SCL = 0;delay_us(4);SDA_IN();
}void  SendNot_Ack(void)
{SDA_OUT();IIC_SCL = 0;delay_us(4);IIC_SDA = 1;delay_us(4);IIC_SCL = 1;delay_us(4);IIC_SCL = 0;delay_us(4);IIC_SDA = 0;delay_us(4);
}void I2C_WriteByte(uint8_t  input)
{uint8_t  i;SDA_OUT();for(i=0; i<8; i++){IIC_SCL = 0;delay_ms(5);if(input & 0x80){IIC_SDA = 1;//delaymm(10);}else{IIC_SDA = 0;//delaymm(10);}IIC_SCL = 1;delay_ms(5);input = (input<<1);}IIC_SCL = 0;delay_us(4);SDA_IN();delay_us(4);
}	uint8_t I2C_ReadByte(void)
{uint8_t  resultByte=0;uint8_t  i=0, a=0;IIC_SCL = 0;SDA_IN();delay_ms(4);for(i=0; i<8; i++){IIC_SCL = 1;delay_ms(3);a=0;if(READ_SDA){a=1;}else{a=0;}//resultByte = resultByte | a;resultByte = (resultByte << 1) | a;IIC_SCL = 0;delay_ms(3);}SDA_IN();delay_ms(10);return   resultByte;
}void  set_AHT20sendOutData(void)
{/* --------------------------* 0xFA 0x06 0x0A temperature(2 Bytes) humility(2Bytes) short Address(2 Bytes)* And Check (1 byte)* -------------------------*/AHT20sendOutData[3] = AHT20_OutData[0];AHT20sendOutData[4] = AHT20_OutData[1];AHT20sendOutData[5] = AHT20_OutData[2];AHT20sendOutData[6] = AHT20_OutData[3];//	AHT20sendOutData[7] = (drf1609.shortAddress >> 8) & 0x00FF;
//	AHT20sendOutData[8] = drf1609.shortAddress  & 0x00FF;//	AHT20sendOutData[9] = getXY(AHT20sendOutData,10);
}void  I2C_Start(void)
{SDA_OUT();IIC_SCL = 1;delay_ms(4);IIC_SDA = 1;delay_ms(4);IIC_SDA = 0;delay_ms(4);IIC_SCL = 0;delay_ms(4);
}void  I2C_Stop(void)
{SDA_OUT();IIC_SDA = 0;delay_ms(4);IIC_SCL = 1;delay_ms(4);IIC_SDA = 1;delay_ms(4);
}

bsp_i2c.h

#ifndef __BSP_I2C_H
#define __BSP_I2C_H#include "sys.h"
#include "delay.h"
#include "usart.h"
//Ê¹ÓÃIIC1 ¹ÒÔØM24C02,OLED,LM75AD,HT1382    PB6,PB7#define SDA_IN()  {GPIOB->CRL&=0X0FFFFFFF;GPIOB->CRL|=(u32)8<<28;}
#define SDA_OUT() {GPIOB->CRL&=0X0FFFFFFF;GPIOB->CRL|=(u32)3<<28;}//IO²Ù×÷º¯Êý	 
#define IIC_SCL    PBout(6) //SCL
#define IIC_SDA    PBout(7) //SDA	 
#define READ_SDA   PBin(7)  //ÊäÈëSDA //IICËùÓÐ²Ù×÷º¯Êý
void IIC_Init(void);                //³õÊ¼»¯IICµÄIO¿Ú				 
void IIC_Start(void);				//·¢ËÍIIC¿ªÊ¼ÐÅºÅ
void IIC_Stop(void);	  			//·¢ËÍIICÍ£Ö¹ÐÅºÅ
void IIC_Send_Byte(u8 txd);			//IIC·¢ËÍÒ»¸ö×Ö½Ú
u8 IIC_Read_Byte(unsigned char ack);//IIC¶ÁÈ¡Ò»¸ö×Ö½Ú
u8 IIC_Wait_Ack(void); 				//IICµÈ´ýACKÐÅºÅ
void IIC_Ack(void);					//IIC·¢ËÍACKÐÅºÅ
void IIC_NAck(void);				//IIC²»·¢ËÍACKÐÅºÅvoid IIC_WriteByte(uint16_t addr,uint8_t data,uint8_t device_addr);
uint16_t IIC_ReadByte(uint16_t addr,uint8_t device_addr,uint8_t ByteNumToRead);//¼Ä´æÆ÷µØÖ·£¬Æ÷¼þµØÖ·£¬Òª¶ÁµÄ×Ö½ÚÊý  void  read_AHT20_once(void);
void  reset_AHT20(void);
void  init_AHT20(void);	
void  startMeasure_AHT20(void);
void  read_AHT20(void);
uint8_t  Receive_ACK(void);
void  Send_ACK(void);
void  SendNot_Ack(void);
void I2C_WriteByte(uint8_t  input);
uint8_t I2C_ReadByte(void);	
void  set_AHT20sendOutData(void);
void  I2C_Start(void);
void  I2C_Stop(void);
#endif

delay.c

#include "delay.h"
#include "sys.h"//STM32F103ºËÐÄ°åÀý³Ì
//¿âº¯Êý°æ±¾Àý³Ì
/********** mcudev.taobao.com ³öÆ·  ********/// 	 
//Èç¹ûÊ¹ÓÃucos,Ôò°üÀ¨ÏÂÃæµÄÍ·ÎÄ¼þ¼´¿É.
#if SYSTEM_SUPPORT_UCOS
#include "includes.h"					//ucos Ê¹ÓÃ	  
#endif
//	 //STM32¿ª·¢°å
//Ê¹ÓÃSysTickµÄÆÕÍ¨¼ÆÊýÄ£Ê½¶ÔÑÓ³Ù½øÐÐ¹ÜÀí
//°üÀ¨delay_us,delay_ms// 	 
static u8  fac_us=0;//usÑÓÊ±±¶³ËÊý
static u16 fac_ms=0;//msÑÓÊ±±¶³ËÊý
#ifdef OS_CRITICAL_METHOD 	//Èç¹ûOS_CRITICAL_METHOD¶¨ÒåÁË,ËµÃ÷Ê¹ÓÃucosIIÁË.
//systickÖÐ¶Ï·þÎñº¯Êý,Ê¹ÓÃucosÊ±ÓÃµ½
void SysTick_Handler(void)
{				   OSIntEnter();		//½øÈëÖÐ¶ÏOSTimeTick();       //µ÷ÓÃucosµÄÊ±ÖÓ·þÎñ³ÌÐò               OSIntExit();        //´¥·¢ÈÎÎñÇÐ»»ÈíÖÐ¶Ï
}
#endif//³õÊ¼»¯ÑÓ³Ùº¯Êý
//µ±Ê¹ÓÃucosµÄÊ±ºò,´Ëº¯Êý»á³õÊ¼»¯ucosµÄÊ±ÖÓ½ÚÅÄ
//SYSTICKµÄÊ±ÖÓ¹Ì¶¨ÎªHCLKÊ±ÖÓµÄ1/8
//SYSCLK:ÏµÍ³Ê±ÖÓ
void delay_init()	 
{#ifdef OS_CRITICAL_METHOD 	//Èç¹ûOS_CRITICAL_METHOD¶¨ÒåÁË,ËµÃ÷Ê¹ÓÃucosIIÁË.u32 reload;
#endifSysTick_CLKSourceConfig(SysTick_CLKSource_HCLK_Div8);	//Ñ¡ÔñÍâ²¿Ê±ÖÓ  HCLK/8fac_us=SystemCoreClock/8000000;	//ÎªÏµÍ³Ê±ÖÓµÄ1/8  #ifdef OS_CRITICAL_METHOD 	//Èç¹ûOS_CRITICAL_METHOD¶¨ÒåÁË,ËµÃ÷Ê¹ÓÃucosIIÁË.reload=SystemCoreClock/8000000;		//Ã¿ÃëÖÓµÄ¼ÆÊý´ÎÊý µ¥Î»ÎªK	   reload*=1000000/OS_TICKS_PER_SEC;//¸ù¾ÝOS_TICKS_PER_SECÉè¶¨Òç³öÊ±¼ä//reloadÎª24Î»¼Ä´æÆ÷,×î´óÖµ:16777216,ÔÚ72MÏÂ,Ô¼ºÏ1.86s×óÓÒ	fac_ms=1000/OS_TICKS_PER_SEC;//´ú±íucos¿ÉÒÔÑÓÊ±µÄ×îÉÙµ¥Î»	   SysTick->CTRL|=SysTick_CTRL_TICKINT_Msk;   	//¿ªÆôSYSTICKÖÐ¶ÏSysTick->LOAD=reload; 	//Ã¿1/OS_TICKS_PER_SECÃëÖÐ¶ÏÒ»´Î	SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk;   	//¿ªÆôSYSTICK    
#elsefac_ms=(u16)fac_us*1000;//·ÇucosÏÂ,´ú±íÃ¿¸ömsÐèÒªµÄsystickÊ±ÖÓÊý   
#endif
}								    #ifdef OS_CRITICAL_METHOD	//Ê¹ÓÃÁËucos
//ÑÓÊ±nus
//nusÎªÒªÑÓÊ±µÄusÊý.		    								   
void delay_us(u32 nus)
{		u32 ticks;u32 told,tnow,tcnt=0;u32 reload=SysTick->LOAD;	//LOADµÄÖµ	    	 ticks=nus*fac_us; 			//ÐèÒªµÄ½ÚÅÄÊý	  		 tcnt=0;told=SysTick->VAL;        	//¸Õ½øÈëÊ±µÄ¼ÆÊýÆ÷Öµwhile(1){tnow=SysTick->VAL;	if(tnow!=told){	    if(tnow<told)tcnt+=told-tnow;//ÕâÀï×¢ÒâÒ»ÏÂSYSTICKÊÇÒ»¸öµÝ¼õµÄ¼ÆÊýÆ÷¾Í¿ÉÒÔÁË.else tcnt+=reload-tnow+told;	    told=tnow;if(tcnt>=ticks)break;//Ê±¼ä³¬¹ý/µÈÓÚÒªÑÓ³ÙµÄÊ±¼ä,ÔòÍË³ö.}  }; 									    
}
//ÑÓÊ±nms
//nms:ÒªÑÓÊ±µÄmsÊý
void delay_ms(u16 nms)
{	if(OSRunning==TRUE)//Èç¹ûosÒÑ¾ÔÚÅÜÁË	    {		  if(nms>=fac_ms)//ÑÓÊ±µÄÊ±¼ä´óÓÚucosµÄ×îÉÙÊ±¼äÖÜÆÚ {OSTimeDly(nms/fac_ms);//ucosÑÓÊ±}nms%=fac_ms;				//ucosÒÑ¾ÎÞ·¨Ìá¹©ÕâÃ´Ð¡µÄÑÓÊ±ÁË,²ÉÓÃÆÕÍ¨·½Ê½ÑÓÊ±    }delay_us((u32)(nms*1000));	//ÆÕÍ¨·½Ê½ÑÓÊ±,´ËÊ±ucosÎÞ·¨Æô¶¯µ÷¶È.
}
#else//²»ÓÃucosÊ±
//ÑÓÊ±nus
//nusÎªÒªÑÓÊ±µÄusÊý.		    								   
void delay_us(u32 nus)
{		u32 temp;	    	 SysTick->LOAD=nus*fac_us; //Ê±¼ä¼ÓÔØ	  		 SysTick->VAL=0x00;        //Çå¿Õ¼ÆÊýÆ÷SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk ;          //¿ªÊ¼µ¹Êý	 do{temp=SysTick->CTRL;}while(temp&0x01&&!(temp&(1<<16)));//µÈ´ýÊ±¼äµ½´ï   SysTick->CTRL&=~SysTick_CTRL_ENABLE_Msk;       //¹Ø±Õ¼ÆÊýÆ÷SysTick->VAL =0X00;       //Çå¿Õ¼ÆÊýÆ÷	 
}
//ÑÓÊ±nms
//×¢ÒânmsµÄ·¶Î§
//SysTick->LOADÎª24Î»¼Ä´æÆ÷,ËùÒÔ,×î´óÑÓÊ±Îª:
//nms<=0xffffff*8*1000/SYSCLK
//SYSCLKµ¥Î»ÎªHz,nmsµ¥Î»Îªms
//¶Ô72MÌõ¼þÏÂ,nms<=1864 
void delay_ms(u16 nms)
{	 		  	  u32 temp;		   SysTick->LOAD=(u32)nms*fac_ms;//Ê±¼ä¼ÓÔØ(SysTick->LOADÎª24bit)SysTick->VAL =0x00;           //Çå¿Õ¼ÆÊýÆ÷SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk ;          //¿ªÊ¼µ¹Êý  do{temp=SysTick->CTRL;}while(temp&0x01&&!(temp&(1<<16)));//µÈ´ýÊ±¼äµ½´ï   SysTick->CTRL&=~SysTick_CTRL_ENABLE_Msk;       //¹Ø±Õ¼ÆÊýÆ÷SysTick->VAL =0X00;       //Çå¿Õ¼ÆÊýÆ÷	  	    
} 
#endif

delay.h

#ifndef __DELAY_H
#define __DELAY_H 			   
#include "sys.h"
//	 //STM32F103ºËÐÄ°åÀý³Ì
//¿âº¯Êý°æ±¾Àý³Ì
/********** mcudev.taobao.com ³öÆ·  ********///Ê¹ÓÃSysTickµÄÆÕÍ¨¼ÆÊýÄ£Ê½¶ÔÑÓ³Ù½øÐÐ¹ÜÀí
//°üÀ¨delay_us,delay_ms// 	 
void delay_init(void);
void delay_ms(u16 nms);
void delay_us(u32 nus);#endif

sys.c

#include "sys.h"//STM32F103ºËÐÄ°åÀý³Ì
//¿âº¯Êý°æ±¾Àý³Ì
/********** mcudev.taobao.com ³öÆ·  ********///	 //STM32¿ª·¢°å
//ÏµÍ³ÖÐ¶Ï·Ö×éÉèÖÃ»¯		   //********************************************************************************  
void NVIC_Configuration(void)
{NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);	//ÉèÖÃNVICÖÐ¶Ï·Ö×é2:2Î»ÇÀÕ¼ÓÅÏÈ¼¶£¬2Î»ÏìÓ¦ÓÅÏÈ¼¶}

sys.h

#ifndef __SYS_H
#define __SYS_H	
#include "stm32f10x.h"
//	 //STM32F103ºËÐÄ°åÀý³Ì
//¿âº¯Êý°æ±¾Àý³Ì
/********** mcudev.taobao.com ³öÆ·  ********/// 	 //0,²»Ö§³Öucos
//1,Ö§³Öucos
#define SYSTEM_SUPPORT_UCOS		0		//¶¨ÒåÏµÍ³ÎÄ¼þ¼ÐÊÇ·ñÖ§³ÖUCOS//Î»´ø²Ù×÷,ÊµÏÖ51ÀàËÆµÄGPIO¿ØÖÆ¹¦ÄÜ
//¾ßÌåÊµÏÖË¼Ïë,²Î¿¼<<CM3È¨ÍþÖ¸ÄÏ>>µÚÎåÕÂ(87Ò³~92Ò³).
//IO¿Ú²Ù×÷ºê¶¨Òå
#define BITBAND(addr, bitnum) ((addr & 0xF0000000)+0x2000000+((addr &0xFFFFF)<<5)+(bitnum<<2)) 
#define MEM_ADDR(addr)  *((volatile unsigned long  *)(addr)) 
#define BIT_ADDR(addr, bitnum)   MEM_ADDR(BITBAND(addr, bitnum)) 
//IO¿ÚµØÖ·Ó³Éä
#define GPIOA_ODR_Addr    (GPIOA_BASE+12) //0x4001080C 
#define GPIOB_ODR_Addr    (GPIOB_BASE+12) //0x40010C0C 
#define GPIOC_ODR_Addr    (GPIOC_BASE+12) //0x4001100C 
#define GPIOD_ODR_Addr    (GPIOD_BASE+12) //0x4001140C 
#define GPIOE_ODR_Addr    (GPIOE_BASE+12) //0x4001180C 
#define GPIOF_ODR_Addr    (GPIOF_BASE+12) //0x40011A0C    
#define GPIOG_ODR_Addr    (GPIOG_BASE+12) //0x40011E0C    #define GPIOA_IDR_Addr    (GPIOA_BASE+8) //0x40010808 
#define GPIOB_IDR_Addr    (GPIOB_BASE+8) //0x40010C08 
#define GPIOC_IDR_Addr    (GPIOC_BASE+8) //0x40011008 
#define GPIOD_IDR_Addr    (GPIOD_BASE+8) //0x40011408 
#define GPIOE_IDR_Addr    (GPIOE_BASE+8) //0x40011808 
#define GPIOF_IDR_Addr    (GPIOF_BASE+8) //0x40011A08 
#define GPIOG_IDR_Addr    (GPIOG_BASE+8) //0x40011E08 //IO¿Ú²Ù×÷,Ö»¶Ôµ¥Ò»µÄIO¿Ú!
//È·±£nµÄÖµÐ¡ÓÚ16!
#define PAout(n)   BIT_ADDR(GPIOA_ODR_Addr,n)  //Êä³ö 
#define PAin(n)    BIT_ADDR(GPIOA_IDR_Addr,n)  //ÊäÈë #define PBout(n)   BIT_ADDR(GPIOB_ODR_Addr,n)  //Êä³ö 
#define PBin(n)    BIT_ADDR(GPIOB_IDR_Addr,n)  //ÊäÈë #define PCout(n)   BIT_ADDR(GPIOC_ODR_Addr,n)  //Êä³ö 
#define PCin(n)    BIT_ADDR(GPIOC_IDR_Addr,n)  //ÊäÈë #define PDout(n)   BIT_ADDR(GPIOD_ODR_Addr,n)  //Êä³ö 
#define PDin(n)    BIT_ADDR(GPIOD_IDR_Addr,n)  //ÊäÈë #define PEout(n)   BIT_ADDR(GPIOE_ODR_Addr,n)  //Êä³ö 
#define PEin(n)    BIT_ADDR(GPIOE_IDR_Addr,n)  //ÊäÈë#define PFout(n)   BIT_ADDR(GPIOF_ODR_Addr,n)  //Êä³ö 
#define PFin(n)    BIT_ADDR(GPIOF_IDR_Addr,n)  //ÊäÈë#define PGout(n)   BIT_ADDR(GPIOG_ODR_Addr,n)  //Êä³ö 
#define PGin(n)    BIT_ADDR(GPIOG_IDR_Addr,n)  //ÊäÈëvoid NVIC_Configuration(void);#endif