DHT11 temperature and humidity sensor AVR microcontroller routine

/************************************************************************
Program: ICC-AVR 
Function: Baud rate 9600 Serial port sends temperature and humidity data  
Data format: humidity temperature checksum For   
          example, the serial port sends data 59 00 24 00 53, then the humidity is 59, the temperature is 24, and the checksum is 53 
Company: DHT11
Chip: M8
Crystal oscillator: external 7.3728Mhz
******************************************************** **********************/
#include
#include
typedef unsigned char U8; /* defined for unsigned 8-bits integer variable Unsigned 8-bit integer variable */
typedef signed char S8; /* defined for signed 8-bits integer variable Signed 8-bit integer variable */
typedef unsigned int U16; /* defined for unsigned 16-bit integer variable /* defined for signed 16-bit integer variable */
typedef signed int S16; /* defined for signed 16-bit integer variable */
typedef unsigned long U32; /* defined for unsigned 32-bit integer variable */
typedef signed long S32; /* defined for signed 32-bit integer variable */
typedef float F32; /* single precision floating point variable (32bits) Single precision floating point number (32-bit length) */
typedef double F64; /* double precision floating point variable (64bits) Double precision floating point number (64-bit length) */

/**************************************************************************
                    I/O space definition
*************************************************************************/
// B0_IN DDRB &= ~(1 << PB0) /*Set input*/
// B0_OUT DDRB |= (1 << PB0) /*Set output*/
// B0_CLR PORTB &= ~(1 << PB0) /*Set low level*/
// B0_SET PORTB |= (1 << PB0) /*Set high level*/
// B0_R PINB & (1 <#define C4_IN DDRC &= ~(1 << PC4) /*Set input*/
#define C4_OUT DDRC |= (1 << PC4) /*Set output*/
#define C4_CLR PORTC &= ~(1 << PC4) /*Set low level*/
#define C4_SET PORTC |= (1 << PC4) /*Set high level*/
#define C4_R PINC & (1 </******************************************************************************
                    Communication I/O space definition
***********************************************************************/
#define COM_IN C4_IN  
#define COM_OUT C4_OUT
#define COM_CLR C4_CLR
#define COM_SET C4_SET
#define COM_R C4_R

/******************************************************************************
                    Global variable definition area
*******************************************************************/
      U8 i;
      U8 U8FLAG,k;
      U8 U8count,U8temp;
      U8    U8T_data_H,U8T_data_L,U8RH_data_H,U8RH_data_L,U8checkdata;
      U8    U8T_data_H_temp,U8T_data_L_temp,U8RH_data_H_temp,U8RH_data_L_temp,U8checkdata_temp;
      U8    U8comdata;
      U16   ReceiveHighByte;
      U16   ReceiveLowByte;
/**************************************************************************
***************************************************************************/
void port_init(void)
{
PORTB = 0x00;
DDRB  = 0xFF;
PORTC = 0x03;                    
DDRC  = 0x0C;
PORTD = 0x00;
DDRD  = 0xF0;
}
void watchdog_init(void)
{
  //WDR();        //this prevents a timout on enabling
  //WDTCR = 0x0F; //WATCHDOG ENABLED - dont forget to issue WDRs
}

void Delay(unsigned int i)
{
while(i--);
}
void DelaymS (U16 dly)                   
{
U16 i;
for ( ; dly>0; dly--)
{
     WDR();
  for (i=0; i<1032; i++);        
}
}

       void  Delay_10us(void)
      {
        U8 i;                     
        i++;i++;i++;i++;i++;i++;i++;i++;i++;
  i++;i++;i++;i++;i++;i++;i++;i++;i++;
  i++;i++;i++;i++;i++;i++;i++;i++;i++;
  i++;i++;i++;i++;i++;i++;i++;i++;i++;
  i++;i++;i++;i++;i++;i++;i++;i++;i++;
  i++;i++;i++;i++;i++;i++;i++;i++;i++;
  i++;i++;i++;i++;i++;i++;i++;i++;i++;
  i++;i++;
       }
        void  COM(void)
      {
     
         U8 i;
       for(i=0;i<8;i++)    
     {
  
         U8FLAG=2;
     while((!(COM_R))&&U8FLAG++);
   if(U8FLAG==1)break;
   Delay_10us();
   Delay_10us();
      Delay_10us();
   Delay_10us();
     U8temp=0;
      if(COM_R)U8temp=1;
      U8FLAG=2;
     while((COM_R)&&U8FLAG++);
     //超时则跳出for循环    
      if(U8FLAG==1)break;
     //判断数据位是0还是1  
        
  // 如果高电平高过预定0高电平值则数据位为 1 
      
     U8comdata<<=1;
        U8comdata|=U8temp;        //0
      }//rof
    
}
//--------------------------------
//-----湿度读取子程序 ------------
//--------------------------------
//----以下变量均为全局变量--------
//----温度高8位== U8T_data_H------
//----温度低8位== U8T_data_L------
//----湿度高8位== U8RH_data_H-----
//----湿度低8位== U8RH_data_L-----
//----校验 8位 == U8checkdata-----
//----调用相关子程序如下----------
//---- Delay();, Delay_10us();,COM(); 
//--------------------------------
void RH(void)
{
  
   //Host pulls down 18ms 
       COM_OUT;
       COM_CLR;
    DelaymS(18);
    COM_IN;
    COM_SET;
   
  //The bus is pulled up by the pull-up resistor and the host delays 20us
    Delay_10us();
    Delay_10us();
    Delay_10us();
    Delay_10us();
  //Host is set as input to judge the response signal of the slave 
  //P2_0=1;
  
  //Judge whether the slave has a low-level response signal. If it does not respond, it will jump out. If it responds, it will run downward.   
   // if(!P2_0) //T !  
    if(COM_R)U8FLAG=1;
    while(!(COM_R))   
    {
    U8FLAG=2;
  //Judge whether the slave sends a low-level response signal of 80us and whether it ends  
    //while((!P2_0)&&U8FLAG++);
    while((!(COM_R))&&U8FLAG++);
    if(U8FLAG==1)break;
    U8FLAG=2;
  //Judge whether the slave sends out a high level of 80us. If so, enter the data receiving state.
  //while((P2_0)&&U8FLAG++);
    while((COM_R)&&U8FLAG++);
    if(U8FLAG==1)break;
  //Data receiving state   
    COM();
    if(U8FLAG==1)break;
    U8T_data_H_temp=U8comdata;
    COM();
    if(U8FLAG==1)break;
    U8T_data_L_temp=U8comdata; 
    COM();
    if(U8FLAG==1)break;
    U8RH_data_H_temp=U8comdata;
    COM();
    if(U8FLAG==1)break;
    U8RH_data_L_temp=U8comdata;
    COM();
    if(U8FLAG==1)break;
    U8checkdata_temp=U8comdata;
    break;
     }//while
    //P2_0=1;
    COM_IN;
    COM_SET;
  //Data check 
  
    U8temp=(U8T_data_H_temp+U8T_data_L_temp+U8RH_data_H_temp+U8RH_data_L_temp);
    if(U8temp==U8checkdata_temp)
    {
       U8RH_data_H=U8T_data_H_temp;
       U8RH_data_L=U8T_data_L_temp;
       U8T_data_H=U8RH_data_H_temp;
       U8T_data_L=U8RH_data_L_temp;
       U8checkdata=U8checkdata_temp;
    }//fi
   
   
    COM_IN;
    COM_SET;
}

/*
Serial port initialization function
System frequency: 2MHz
Stop bit: 1
Baud rate: 9600
Data length: 8
*/
void Uart_Init(void) {
UCSRA = 0x02; /*2x speed */
UCSRB = 0x18; /*Allow receiving and sending*/
UCSRC = 0x06; /*8-bit data */
UBRRH = 0x00;
//UBRRL = 47; /*9600 3.6864M */  
UBRRL = 95; /*9600 7.3728M */ 
}
/*
Send string data in
query mode
*/
void Uart_Transmit(unsigned char i) {
/* Wait for the send buffer to be empty*/
while (!(UCSRA & (1</* Put data into the buffer and send data*/
UDR = i;
}
/*
Receive string data
in query mode
*/
unsigned char Uart_Receive( void ) {
/* Wait for receiving data*/
while (!(UCSRA & (1</* Get and return data from the buffer*/
// Uart_Transmit(UDR);
return UDR;
}
void init_devices(void) 
{
unsigned char i;
     CLI();                     
     port_init();
watchdog_init();
    Uart_Init();
    MCUCR = 0x03;
    GICR = 0x00; // Turn off external interrupt 0
    TIMSK = 0x00; // Turn off timer 1 interrupt
           SEI(); //re-enable interrupts
                           
} 
/******************************************************************************

                            Main function
       
       
       
       
**************************************************************************/

void main(void)
{
init_devices() ;
COM_IN;
COM_SET;

while(1)
{

//Read DHT11   
  RH();
  
  //Convert the hexadecimal data of DHT11 into decimal format  
  //Humidity Temperature Checksum   
  //For example, if the serial port sends data 59 00 24 00 53, the humidity is 59, the temperature is 24, and the checksum is 53 
  
  
  
  U8temp=U8RH_data_H/10;
  U8temp<<=4;
  U8temp|=U8RH_data_H%10;
  U8RH_data_H=U8temp;
  Uart_Transmit(U8RH_data_H); 
  Uart_Transmit(U8RH_data_L);
  
  U8temp=U8T_data_H/10;
  U8temp<<=4;
  U8temp|=U8T_data_H%10;
  U8T_data_H=U8temp;
  Uart_Transmit(U8T_data_H);  
  Uart_Transmit(U8T_data_L); 
  
  Uart_Transmit(U8checkdata); 
  //Delay 2S
  for(U8temp=0;U8temp<200;U8temp++)
  {
  DelaymS(10);

  }//rof
  
}

}