建議先看一下 I2C 的規格後再來討論此問題。

Philips 的規格 : http://www.nxp.com/acrobat_download/literature/9398/39340011.pdf

dsPIC30F Peripheral Module -- I2C 裡的練習一

我用示波器量測 SDA &　SCL　發現它固定傳出資料在此
請問它的值代表的意義或是哪一個變數之值。。謝謝
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#include <p30F4011.h>
#include <I2C.h>
#include "I2CSubs.h"

#define REPORT_NACK { \
IFS0bits.MI2CIF = 0 ; \
StopI2C( ) ; \
while ( I2CCONbits.PEN ) ; \
return -1 ; \
}

unsigned char I2C_ACKPolling(unsigned char CMD)
{
unsigned char ACK_Result ;
IdleI2C( ) ;
StartI2C( ) ;
while ( I2CCONbits.SEN) ;
// Send START bit ! SEN will be clear automatically once START bits completed
IFS0bits.MI2CIF = 0 ;
MasterWriteI2C((CMD & 0xFE)) ;
while(! IFS0bits.MI2CIF ) ;
// MI2CIF will be clear after data transmitted completely !
if ( I2CSTATbits.ACKSTAT ) ACK_Result = 1 ;
else ACK_Result = 0 ;
IFS0bits.MI2CIF = 0 ;
StopI2C( ) ;
while ( I2CCONbits.PEN ) ;
return ACK_Result ;
}

void Init_I2C(void)
{
unsigned int config1 , config2 ;

config2 = 0xff;
config1 = I2C_ON & I2C_IDLE_STOP&I2C_CLK_REL
& I2C_IPMI_DIS & I2C_7BIT_ADD
& I2C_SLW_DIS & I2C_SM_DIS
& I2C_GCALL_DIS & I2C_STR_DIS
& I2C_NACK & I2C_ACK_DIS & I2C_RCV_DIS
& I2C_STOP_DIS & I2C_RESTART_DIS
& I2C_START_DIS ;

ConfigIntI2C(MI2C_INT_OFF & MI2C_INT_PRI_0 ) ;
OpenI2C(config1,config2) ;

// TRISFbits.TRISF2 = 1 ;
// TRISFbits.TRISF3 = 1 ;
}

int EEPROM_ByteWrite(unsigned char CMD , unsigned char Addr , unsigned char Data )
{
IdleI2C( ) ;
StartI2C( ) ;

while ( I2CCONbits.SEN) ; // Send START bit ! SEN will be clear automatically once START bits completed

IFS0bits.MI2CIF = 0 ;
MasterWriteI2C((CMD & 0xFE)) ;
while(! IFS0bits.MI2CIF ) ; // MI2CIF will be clear after data transmitted completely !

if ( I2CSTATbits.ACKSTAT )
REPORT_NACK


IFS0bits.MI2CIF = 0 ;
MasterWriteI2C(Addr) ;
while(! IFS0bits.MI2CIF ) ;

if ( I2CSTATbits.ACKSTAT )
REPORT_NACK


IFS0bits.MI2CIF = 0 ;
MasterWriteI2C(Data) ;
while(! IFS0bits.MI2CIF ) ;

if ( I2CSTATbits.ACKSTAT )
REPORT_NACK


IFS0bits.MI2CIF = 0 ;
StopI2C( ) ;
while ( I2CCONbits.PEN ) ;

return 0 ;

}


int EEPROM_ByteRead(unsigned char CMD , unsigned char Addr )
{
unsigned char Temp_Buffer ;

unsigned ReadDelay ;

IdleI2C( ) ;
StartI2C( ) ;
while ( I2CCONbits.SEN) ;

IFS0bits.MI2CIF = 0 ;
MasterWriteI2C((CMD & 0xFE)) ; // Mask bit 0 -> Write command
while(! IFS0bits.MI2CIF ) ;

if ( I2CSTATbits.ACKSTAT )
REPORT_NACK

IFS0bits.MI2CIF = 0 ;
MasterWriteI2C(Addr) ;
while(! IFS0bits.MI2CIF ) ;

if ( I2CSTATbits.ACKSTAT )
REPORT_NACK

IFS0bits.MI2CIF = 0 ;
RestartI2C( ) ;
while ( I2CCONbits.RSEN) ;

IFS0bits.MI2CIF = 0 ;
MasterWriteI2C((CMD | 0x01)) ; // Set bit 0 for "Read" command
while(! IFS0bits.MI2CIF ) ;

if ( I2CSTATbits.ACKSTAT )
REPORT_NACK

IFS0bits.MI2CIF = 0 ;

Temp_Buffer = MasterReadI2C( ) ;
while(! IFS0bits.MI2CIF ) ;

IFS0bits.MI2CIF = 0 ;
NotAckI2C( ) ;
while(! IFS0bits.MI2CIF ) ;
IFS0bits.MI2CIF = 0 ;

StopI2C( ) ;
while ( I2CCONbits.PEN ) ;

return (int)Temp_Buffer ;

}