i2ctestmaster.c

pic单片机作为I2C从机的通讯程序

     delayus(10);
// start convertion and wait for interrupt
     GODONE=1;
}


void delayus(unsigned char time)
{
    time=time/2;
    while(time-->0)
    {
        NOP();
    }
    
}

void delayms(unsigned char time)
{
    unsigned char i=0;
    unsigned int j=0;
    for(i=0;i<time;i++)
    {
        for(j=0;j<1000;j++)
        {
            NOP();
            NOP();
            NOP();
            CLRWDT();
        }
    }
}

//---------name:device_initial---------//
//input: none
//output:none
//------function :initial device-------//
void device_initial(void)
{
// disable all interrupt     
     PEIE=0;
	 GIE=0;
// config rxd as digital io not a/d channel,important    
     ANSEL=0x00;
     ANSELH=0x00;
// config RC0 as led 
     PORTC=0x00;
     TRISC0=0;
     RC0=0;
     PORTA=0x00;
     //TRISA2=1;
     RABPU=0;
     SCL_Derection=0;
     SCL=1;
     SDA_Derection=0;
     SDA=1;
// watch dog and timer0 config
     timer0_initial();
     timer1_initial();
   //  Slave_I2C_Initial();
     uart_initial();
   //  ad_initial();    
// enable all interrupt     
     PEIE=1;
	 GIE=1; 
     CLRWDT();   
         
}
//---------name:timer0_initial---------//
//input: none
//output:none
//------function :initial timer0-------//
void timer0_initial(void)
{
    TMR0=0x00;
// internal instruction cycle
    T0CS=0;
//prescaler is for watch dog,1:8
    OPTION=0xDB;
    T0IE=0;
//enable watch dog,8 second reset
    WDTCON=0x15;
    CLRWDT();
} 
//---------name:timer1_initial---------//
//input: none
//output:none
//------function :initial timer1-------// 
void timer1_initial(void)
{
    TMR1IE=0;
// internal clock,8 divide,
    T1CON=0x30;
//10ms for interrupt
    TMR1L=0xD8;
    TMR1H=0xF1;
//enable interrupt
    TMR1IE=1;
    TMR1ON=1;
    CLRWDT();
}  
//---------name:uart_deal_service---------//
//input: none
//output:none
//------function :uart deal events-------// 
void uart_deal_service(void)
{
    Rx_Start=0;
    Rx_Over=0;
    CLRWDT();
    uart_send_data(Buffer2,URT_ptr); 
    ad_test();;
}
//----------name:ad_deal_service-----------//
//input: none
//output:none
//------function :a/d finish,routine-------// 
void ad_deal_service(void)
{
    Ad_Over=0;
    CLRWDT();
    uart_send_data(Ad_Buffer,2); 
    
}
//----------name:i2c_rd_deal-----------//
//input: none
//output:none
//------function :master read over-----//
void i2c_rd_deal(void)
{
    I2c_Rd_Over=0;;
}
//----------name:i2c_wr_deal-----------//
//input: none
//output:none
//-----function :master write over-----//
void i2c_wr_deal(void)
{
    I2c_Wr_Start=0;
    I2c_Wr_Over=0;
}
//------------name:pulse_test------------//
//input: none
//output:none
//---function :test the width of pulse---//
void pulse_test(void)
{
    unsigned char timer0_count[3]={0,0,0};
    unsigned int count=0;
    second10ms=0;
       
wait1:
    if(RA2==1)
    {
        if(second10ms>10)
            return;
        goto wait1;
    }  
wait2:
    if(RA2==0)
    {
        if(second10ms>10)
            return;
        TMR0=0x00;
        CLRWDT();
        goto wait2;
    }
    while(1)
    {
        if(RA2==1)
        { 
            if(T0IF==1)
            {
                T0IF=0;
                count++; 
                          
            }
        }
        else
        {
            T0IE=0;
            break;
        }
        
    }
    timer0_count[2]=TMR0;
    timer0_count[0]=(count>>8)&0xff;
    timer0_count[1]=(unsigned char)count&0xff;
    //T0IE=0;
    uart_send_data(timer0_count,3);
    return;
}
//***************************************************************************************
//函数：void I2C_Start(void)
//功能：I2C起始条件，启动总线
//输入：
//输出：无
//=======================================================================================
void I2C_Start(void)
{
     SDA_Derection=0;
     //SDA_Derection=1;//
     NOP();
     NOP();
     SDA=1;
    // SDA_Derection=1;//
     NOP();
     SCL=1;
     //SCL_Derection=1;//
     NOP();
     NOP();
     NOP();
     NOP();
     NOP();
     SDA=0;
     //SDA_Derection=0;//
     NOP();
     NOP();
     NOP();
     NOP();
     NOP();
     SCL=0;
     //SCL_Derection=0;//
     NOP();
     NOP();
}
//***************************************************************************************
//函数：void I2C_Stop(void)
//功能：结束I2C总线信号
//输入：
//      
//输出：无
//=======================================================================================
void I2C_Stop(void)
{
    SDA_Derection=0;
    NOP();
    NOP();
    SDA=0;
    NOP();
    SCL=1;
   // SCL_Derection=1;//
    NOP();
    NOP();
    NOP();
    NOP();
    NOP();
    SDA=1;
   // SDA_Derection=1;//
    NOP();
    NOP();
    NOP();
    NOP();
    SDA_Derection=1;
}
//***************************************************************************************
//函数：unsigned char I2C_CheckAcK(void)
//功能：检验I2C总线应答信号，有应答返回1，否则返回0
//输入：
//
//输出：0,失败；1，成功
//=======================================================================================
unsigned char I2C_CheckAcK(void)
{
    unsigned char Err_time=255;
    SDA_Derection=0;
    SDA=1;
    SDA_Derection=1;
    NOP();
    NOP();
    NOP();
    SCL=1;
    //SCL_Derection=1;//
    NOP();
    NOP();
    NOP();
    NOP();
    NOP();
    while(SDA)
    {
        Err_time--;
        if(Err_time==0)
        {
            I2C_Stop();
            return 0x00;
        }
    }
    SCL=0;
    //SCL_Derection=0;//
    NOP();
    NOP();
    return 0x01;
}

//***************************************************************************************
//函数：void I2C_SendB(unsigned char c)
//功能：向I2C总线发送一个字节
//输入：要发送的数据字节
//
//输出：无
//=======================================================================================
void I2C_SendB(unsigned char c)
{
    unsigned char i,j;
    SDA_Derection=0;
    for(i=0;i<8;i++)
    {
        if((c<<i)&0x80)
        {
            SDA=1;
            //SDA_Derection=1;
        }
        else 
        {
            SDA=0;
            //SDA_Derection=0;
        }
        NOP();
        NOP();
        SCL=1;
        //SCL_Derection=1;//
        NOP();
        NOP();
        NOP();
        NOP();
        NOP();
        
        SCL=0;
        //SCL_Derection=0;//
    }
    NOP();
    NOP();
    I2C_Ack=I2C_CheckAcK();
    NOP();
    NOP();
}

//***************************************************************************************
//函数：unsigned char I2C_RceB(void)
//功能：从I2C总线上接收1个字节
//输入：无
//      
//输出：所接收的1个字节数据
//=======================================================================================
unsigned char I2C_RceB(void)
{
    unsigned char i,Rcdata;
    Rcdata=0;
    SDA_Derection=1;
    //delayus(8);//
    //SCL_Derection=1;//
    delayus(20);//
    //while(!SCL);
   // SCL_Derection=0;
   // SCL=1;
    for(i=0;i<8;i++)
    {
        NOP();
        SCL=0;
        //SCL_Derection=0;//
        NOP();
        NOP();
        NOP();
        NOP();
        SCL=1;
        //SCL_Derection=1;//
        NOP();
        NOP();
        Rcdata=Rcdata<<1;
        if(SDA==1)
        {
            Rcdata=Rcdata+1;
        }
        NOP();
        NOP();
    }
    SCL=0;
   // SCL_Derection=0;//
    NOP();
    NOP();
    return (Rcdata);
}

//***************************************************************************************
//函数：void I2C_Ackn(unsigned char a)
//功能：接收数据后向I2C总线发送应答或非应答信号
//输入：0 发送应答信号，数据接收未完成
//      1 发送非应答信号，数据接收完毕
//输出：无
//=======================================================================================
void I2C_Ackn(unsigned char a)
{
    SDA_Derection=0;
    
    if(a==0)
    {
        SDA=0;
        //SDA_Derection=0;//
    }
    else 
    {
        SDA=1;
        //SDA_Derection=1;//
    }
    NOP();
    NOP();
    NOP();
    SCL=1;
   // SCL_Derection=1;//
    NOP();
    NOP();
    NOP();
    NOP();
    NOP();
    SCL=0;
    //SCL_Derection=0;//
    NOP();
    NOP();
}


//***************************************************************************************
//函数：unsigned char Send_Nbyte(unsigned char len,unsigned char *p)
//功能：向I2C总线发送N个字节
//输入：len:写入数据的字节长度
//      p:数组的指针
//输出：0，发送失败；1，发送成功
//=======================================================================================
unsigned char Send_Nbyte(unsigned char len,unsigned char *p)
{
    unsigned char i;
    I2C_Start();
    I2C_SendB(0x02);
    for(i=0;i<len;i++)
    {
        I2C_SendB(*(p+i));
        if(!I2C_Ack)
        {
            //RC0=1;
            return 0;
        }
        
    }
    //RC0=1;
    I2C_Stop();
    return 1;
}
//***************************************************************************************
//函数：unsigned char Read_RTC(unsigned char*timeptr)
//功能：从时钟芯片读时钟
//输入：接收时钟区指针，接收长度为7字节，分别为秒，分，时，星期，日，月，年
//
//输出：0 表示读取失败；1 表示读取成功；
//=======================================================================================
unsigned char Read_Nbyte(unsigned char num)
{
    unsigned char i;
    I2C_Start();
    I2C_SendB(0x03);
    if(!I2C_Ack)
    {
        RC0=0;
        return 0;
    }
    else 
        RC0=1;
    //delayus(8);
    for(i=0;i<num;i++)
    {
        *(I2C_Buff+i)=I2C_RceB();
        if(i<num-1)
        {
            I2C_Ackn(0);
        }
        else 
        {
            I2C_Ackn(1);
        }
        //delayus(24);//18
    }
    I2C_Stop();
    return 1;
}