at24c02

24c02读写程序

* Name:AT24C02存储器的读写程序,用到I2C总线,含相对独立的I2C总线读写函数 */ 
    #include 
    #include 
    #include 
    #define DELAY_TIME 60 /*经实验，不要小于50！否则可能造成时序混乱*/ 
    #define TRUE 1 
    #define FALSE 0 
    sbit SCL=P1^7;/*假设由P1.7和P1.6控制*/ 
    sbit SDA=P1^6; 

/********** Function Definition　函数定义 ************/ 

    void DELAY(unsigned int t) /*延时函数*/ 
    { 
        while(t!=0) 
            t--; 
    } 

    void I2C_Start(void) 
    { 
        /*启动I2C总线的函数，当SCL为高电平时使SDA产生一个负跳变*/ 
        SDA=1; 
        SCL=1; 
        DELAY(DELAY_TIME); 
        SDA=0; 
        DELAY(DELAY_TIME); 
        SCL=0; 
        DELAY(DELAY_TIME); 
    } 

    void I2C_Stop(void) 
    { 
        /*终止I2C总线，当SCL为高电平时使SDA产生一个正跳变*/ 
        SDA=0; 
        SCL=1; 
        DELAY(DELAY_TIME); 
        SDA=1; 
        DELAY(DELAY_TIME); 
        SCL=0; 
        DELAY(DELAY_TIME); 
    } 

    void SEND_0(void)   /* SEND ACK */ 
    { 
        /*发送0，在SCL为高电平时使SDA信号为低*/ 
        SDA=0; 
        SCL=1; 
        DELAY(DELAY_TIME); 
        SCL=0; 
        DELAY(DELAY_TIME); 
    } 

    void SEND_1(void) 
    { 
        /*发送1，在SCL为高电平时使SDA信号为高*/ 
        SDA=1; 
        SCL=1; 
        DELAY(DELAY_TIME); 
        SCL=0; 
        DELAY(DELAY_TIME); 
    } 

    bit Check_Acknowledge(void) 
    { 
        /*发送完一个字节后检验设备的应答信号*/ 
        SDA=1; 
        SCL=1; 
        DELAY(DELAY_TIME/2); 
        F0=SDA; 
        DELAY(DELAY_TIME/2); 
        SCL=0; 
        DELAY(DELAY_TIME); 
        if(F0==1) 
            return FALSE; 
        return TRUE; 
    } 

    void WriteI2CByte(char b)reentrant 
    { 
        /*向I2C总线写一个字节*/ 
        char i; 
        for(i=0;i<8;i++) 
            if((b<                SEND_1(); 
            else 
                SEND_0(); 
    } 

 

    char ReadI2CByte(void)reentrant 
    { 
        /*从I2C总线读一个字节*/ 
        char b=0,i; 
        for(i=0;i<8;i++) 
        { 
            SDA=1;    /*释放总线*/ 
            SCL=1;    /*接受数据*/ 
            DELAY(10); 
            F0=SDA; 
            DELAY(10); 
            SCL=0; 
            if(F0==1) 
                { 
                    b=b<<1; 
                    b=b|0x01; 
                 } 
            else 
                b=b<<1; 
        } 
        return b; 
    } 


/**********以下为读写24c02的函数**********/ 
void Write_One_Byte(char addr,char thedata) 
{ 
          bit acktemp=1; 
          /*write a byte to mem*/ 
          I2C_Start(); 
          WriteI2CByte(0xa0); 
          acktemp=Check_Acknowledge(); 
          WriteI2CByte(addr);/*address*/ 
          acktemp=Check_Acknowledge(); 
          WriteI2CByte(thedata);/*thedata*/ 
          acktemp=Check_Acknowledge(); 
          I2C_Stop(); 

} 

void Write_A_Page(char *buffer,char addr) 
{ 
          bit acktemp=1; 
          bit wrtmp; 
          int i; 
          /*write a page to at24c02*/ 
          I2C_Start(); 
          WriteI2CByte(0xa0); 
          acktemp=Check_Acknowledge(); 
          WriteI2CByte(addr);/*address*/ 
          acktemp=Check_Acknowledge(); 
          for(i=0;i<7;i++) 
          { 
            WriteI2CByte(buffer[i]); 
            if(!Check_Acknowledge()) 
                { 
                    I2C_Stop(); 

                } 
           } 


          I2C_Stop(); 

 


} 

char Read_One_Byte(char addr) 
{         bit acktemp=1; 
          char mydata; 
           /*read a byte from mem*/ 
          I2C_Start(); 
          WriteI2CByte(0xa0); 
          acktemp=Check_Acknowledge(); 
          WriteI2CByte(addr);/*address*/ 
          acktemp=Check_Acknowledge(); 
          I2C_Start(); 
          WriteI2CByte(0xa1); 
          acktemp=Check_Acknowledge(); 


          mydata=ReadI2CByte(); 
          acktemp=Check_Acknowledge(); 

          return mydata; 
          I2C_Stop(); 
} 

void Read_N_Bytes(char *buffer,char n,char addr) 
{ 
          bit acktemp=1; 

          int i=0; 
           /*read 8 bytes from mem*/ 
          I2C_Start(); 
          WriteI2CByte(0xa0); 
          acktemp=Check_Acknowledge(); 
          WriteI2CByte(addr);/*address*/ 
          acktemp=Check_Acknowledge(); 
          I2C_Start(); 
          WriteI2CByte(0xa1); 

          acktemp=Check_Acknowledge(); 

 


          for(i=0;i          { 
                buffer[i]=ReadI2CByte(); 
                if(i!=n-1) 
                    SEND_0();    /*发送应答*/ 
                else 
                    SEND_1();    /*发送非应答*/ 
          } 

   I2C_Stop(); 

} 


void main() 
{ 
          int i; 
          char mybyte; 
          char myarray[8]; 
          char myarray2[8]; 
          char rdarray[16]; 
           
          for(i=0;i<8;i++) 
          { 
                myarray[i]=i; 
                myarray2[i]=i+0x08;      

          } 

          Write_One_Byte(0x20,0x28); 

          Write_A_Page(myarray,0x10); 
          Write_A_Page(myarray2,0x18); 

          mybyte=Read_One_Byte(0x20); 
          Read_N_Bytes(rdarray,16,0x10); 

}