i2c.c

一个带收音的功放程序, VFD显示驱动用一个非常实用的方法, 稍加修改即可换成不同的VFD, 功放芯片用M61538

//***************************************************************
// 	I2C functions for ST72321 - master mode only
//  Function    : Delay10us
//  Description : delay 10us each time is called
//                can be modified for different CPU speed
// **************************************************************
#include  "reg52.h"
#include  "..\..\inc\globedef.h"
#include  "..\..\inc\i2c.h"   
#include  "..\..\inc\delay.h"


//***************************************************************
// 	Send start condition
// 	ensure data is high then issue a start condition
// 	see also i2c_Start() macro
//***************************************************************
void I2C_Start (void)
{
    	Pin_I2CSDA = 1;
		Delay5US();
		Delay5US();
      	Pin_I2CSCL = 1; 
		Delay5US();
      	Delay5US();
      	Pin_I2CSDA = 0; 
      	Delay5US();	
      	Delay5US();
      	Delay5US();
      	Pin_I2CSCL = 0;  	
}

//***************************************************************
//  	Send stop condition
//  	data low-high while clock high
//***************************************************************
void I2C_Stop (void)
{
    	Pin_I2CSDA = 0; 	
      	Delay5US();
    	Pin_I2CSCL = 1; 	
    	Delay5US();
    	Delay5US();
    	Pin_I2CSDA = 1; 	
}

//***************************************************************
//ROUTINE NAME : I2C_Ack
//INPUT/OUTPUT : None.
//DESCRIPTION  : Acknoledge generation from now.
//COMMENTS     : Transfer sequence = DATA, ACK.
//***************************************************************

void I2C_Rack(void)
{
	
		Pin_I2CSCL = 0;
		Pin_I2CSDA = 1;
       	Delay5US();       
       	Delay5US();        
       	Pin_I2CSCL = 1;
       	Delay5US();      
       	Delay5US(); 
       	Delay5US(); 
       	Pin_I2CSDA = 0;
       	Pin_I2CSCL = 0;       	 
       	Delay5US();       	
       	
}
/*
void I2C_Ack (void)
{
    
       	
       	Pin_I2CSCL = 0;
       	Delay5US();      	
        Pin_I2CSDA = 0;
       	Delay5US();   
    	Pin_I2CSCL = 1;
       	Delay5US();
       	Pin_I2CSCL = 0;
       	Delay5US();
        Pin_I2CSDA = 1;
     
    
}
*/

//***************************************************************
//ROUTINE NAME : I2C_nAck
//INPUT/OUTPUT : None.
//DESCRIPTION  : Non acknoledge generation from now.
//COMMENTS     : Transfer sequence = DATA, NACK.
//***************************************************************
void I2C_nAck (void)
{
    	Pin_I2CSCL = 0;
       	Delay5US();
    	Pin_I2CSDA = 1;
       	Delay5US();        
    	Pin_I2CSCL = 1;
       	Delay5US();
       	Delay5US();
       	Delay5US();
       	Pin_I2CSCL = 0;
       	Delay5US();
        Pin_I2CSDA = 1;
}

//***************************************************************
// 	Send a byte to the slave
// 	return I2C_ERROR on error
//***************************************************************
void I2C_TxData (BYTE i2c_data)
{
	BYTE send_i;

	for(send_i=0; send_i<8; send_i++)
	{
		Pin_I2CSCL = 0; 	
		Delay5US();		
		if(i2c_data & 0x80)
			Pin_I2CSDA = 1;
		else
			Pin_I2CSDA = 0;
		Delay5US();	
		Pin_I2CSCL = 1; 	
		Delay5US();			
		i2c_data <<= 1;
	}
	
}

//***************************************************************
//ROUTINE NAME : I2Cm_RxData
//INPUT/OUTPUT : Last byte to receive flag (active high)/Received data byte.
//DESCRIPTION  : Receive a data byte.
//COMMENTS     : Transfer sequence = DATA, ACK, EV7...
//***************************************************************
BYTE I2C_RxData (void)
{   
    BYTE read_i;
    BYTE readbyte=0; 
    Pin_I2CSCL = 0; 		
	Pin_I2CSDA = 1;	
	Delay5US();

	for(read_i=0; read_i<8; read_i++)
	{
		Pin_I2CSCL = 1; 
		readbyte <<= 1;
		Delay5US();
		if(Pin_I2CSDA)
			readbyte |= 0x01;
		
		Pin_I2CSCL = 0; 	
		Delay5US();		
		
	}  
	return readbyte;

} 
//***************************************************************
//ROUTINE NAME : I2Cm_SetAddr
//INPUT/OUTPUT : external I2C device address / None.
//DESCRIPTION  : Generates Start-bit and transmits the address byte.
//COMMENTS     : Transfer sequence = START, EV5, ADD, ACK...
//***************************************************************
void I2C_SetAddr(char i2c_addr)
{
    I2C_TxData (i2c_addr);
}



//***************************************************************
//    Send a byte to the slave and acknowledges the transfer
//    return I2C_ERROR, or I2C_OK
//***************************************************************


void  I2C_PutByte(BYTE DevAddr,BYTE subAddr, BYTE ucData)
{
    I2C_Start();
    I2C_SetAddr(DevAddr); 
    I2C_Rack();
    I2C_SetAddr(subAddr);     
    I2C_Rack();    
    I2C_TxData(ucData);
    I2C_Rack();    
    I2C_Stop();
}


//***************************************************************
//    Get a byte from the slave and acknowledges the transfer
//    return I2C_OK or I2C_ERROR
//***************************************************************


BYTE  I2C_GetByte(BYTE DevAddr,BYTE subAddr)
{
    BYTE  ucData;
	
    I2C_Start ();
    I2C_SetAddr(DevAddr); 
    I2C_Rack();
    I2C_SetAddr(subAddr);     
    I2C_Rack();

    I2C_Start ();
    I2C_SetAddr(DevAddr+1);  
    I2C_Rack();
    ucData = I2C_RxData();                                               
    
    I2C_nAck();               

    I2C_Stop();
    return(ucData);
}

//***************************************************************
//     Send an array of bytes to the slave 
//     -and acknowledges the transfer
//     return I2C_OK or I2C_ERROR
//***************************************************************

/*
void  I2C_PutString(BYTE DevAddr,BYTE subAddr, BYTE *str, BYTE length)
{
    BYTE send_cc;
    send_cc = 0;
    I2C_Start ();
    I2C_SetAddr(DevAddr); 
    I2C_Rack();
    I2C_SetAddr(subAddr);     
    I2C_Rack();

    while(length)
    {
       I2C_TxData(*str);
       I2C_Rack();       
       length--;
       send_cc++;
       if(length > 0)
       str++;
       
       
       if((send_cc % 8 == 0) && (length > 0))
       {
           I2C_Stop();
           DelayX1ms(4);
           
           {
	   		I2C_Start ();
			I2C_SetAddr(DevAddr); 
			I2C_Rack();
	   		I2C_SetAddr(subAddr+send_cc);     
		   	I2C_Rack();
		   }
           
       }
    }
    I2C_Stop();
}

*/

/*
void  I2C_OutString(BYTE DevAddr,BYTE subAddr, BYTE *str, BYTE length)
{
    BYTE CCC;
    I2C_Start ();
    I2C_SetAddr(DevAddr); 
    I2C_Rack();
    I2C_SetAddr(subAddr);     
    I2C_Rack();

    while(length)
    {
     
       I2C_TxData(*str);
       I2C_Rack();       
       length--;
      
       if(length > 0)
       str++;
    }
    I2C_Stop();
    for(CCC = 0; CCC <2;CCC++)
    ;
    
}
*/
//***************************************************************
//     Reads number bytes from the slave, stores them at str 
//     -and acknowledges the transfer
//     return I2C_OK or I2C_ERROR not successfully read
//***************************************************************

/*
void  I2C_GetString(BYTE DevAddr,BYTE subAddr, BYTE *str, BYTE number)
{
    I2C_Start ();
    I2C_SetAddr(DevAddr); 
    I2C_Rack();
    I2C_SetAddr(subAddr);     
    I2C_Rack();

    I2C_Start ();
    I2C_SetAddr(DevAddr+1);  
    I2C_Rack();
    
    while(number)
    {
	   	*str = I2C_RxData();
		if (number==1)        
	    		I2C_nAck();      
	    	else
	    		I2C_Ack();       
	    	str++;
		number -= 1;
    }
    I2C_Stop();
}
*/