www.pudn.com > i2c111.rar > i2c.C

void I2cWait(void)    //file://延/时，I2c大约30k/s 
{ 
  unsigned char i; 
 
  for(i=0;i<10;i++) 
  { 
    i=i;//_nop_(); 
  } 
} 
 
void I2cStart(void)   // file://起/始信号 
{ 
  SDA = 1; 
  SCL = 1; 
  I2cWait(); 
  SDA = 0; 
  I2cWait(); 
  SCL = 0; 
} 
 
void I2cStop(void)    //file://停/止信号 
{ 
  SDA = 0; 
  I2cWait(); 
  SCL = 1; 
  I2cWait(); 
  SDA = 1; 
  I2cWait(); 
} 
 
void SendAck(bit ack)  //  file://送/确认信号到slave 
{ 
  SDA = ack; 
  SCL = 1; 
  I2cWait(); 
  SCL = 0; 
} 
 
bit I2cSendByte(unsigned char bytedata)  //file://送/一字节数据到slave 
{ 
  unsigned char i; 
  bit ack; 
 
  for(i=0;i<8;i++) 
  { 
    if(bytedata & 0x80) 
      SDA = 1; 
    else 
      SDA = 0; 
 
    bytedata <<= 1; 
    I2cWait(); 
 
    SCL = 1; 
    I2cWait(); 
    SCL = 0; 
    I2cWait(); 
  } 
 
  SDA = 1; 
  I2cWait(); 
  SCL = 1; 
  I2cWait(); 
 
  ack = SDA;     // file://接/收确认信号:1,没收到应答；0，收到应答 
 
  SCL = 0; 
  I2cWait(); 
 
  return ack; 
} 
 
unsigned char I2cReceiveByte(void)  //file://接/收1字节数据 
{ 
  unsigned char i; 
  unsigned char bytedata = 0; 
 
  for(i=0;i<8;i++) 
  { 
    SCL = 1; 
    I2cWait(); 
 
    bytedata <<= 1; 
 
    if(SDA) 
    { 
      bytedata |= 0x01; 
    } 
    SCL = 0; 
    I2cWait(); 
  } 
 
  return bytedata; 
} 
 
unsigned char I2cByteRead(unsigned char device,unsigned char address) 
{      //file://从/slave接收1字节数据 
  unsigned char bytedata; 
 
  I2cStart(); 
  I2cSendByte(device); 
  I2cSendByte(0); 
  I2cSendByte(address); 
  I2cStart(); 
  I2cSendByte(device|0x01); 
  bytedata = I2cReceiveByte(); 
  SendAck(1); 
  I2cStop(); 
 
  return bytedata; 
} 
 
 
void I2cByteWrite(unsigned char device,unsigned int address,unsigned char bytedata) 
{      //file://将/数据写入指定slave的地址内 
   unsigned char i; 
   unsigned char addressh,addressl; 
   bit ack; 
 
   addressl = address&0xFF; 
   addressh = address>>8; 
   for(i=0;i<10;i++) 
   { 
     I2cStart(); 
     ack = I2cSendByte(device); 
     if(ack==1) 
     { 
       I2cStop(); 
       continue; 
     } 
     ack = I2cSendByte(addressh); 
     if(ack==1) 
     { 
       I2cStop(); 
       continue; 
     } 
     ack = I2cSendByte(addressl); 
     if(ack==1) 
     { 
       I2cStop(); 
       continue; 
     } 
     ack = I2cSendByte(bytedata); 
     if(ack==1) 
     { 
       I2cStop(); 
       continue; 
     } 
     I2cStop(); 
     if(ack==0)  break;    //file://正/常，跳出循环 
   } 
//   DelayX5ms(2); 
}