STM8 I/O口模拟I2C
#define I2C_ERR 0
#define I2C_CRR 1
#define I2CDataIn 1
#define I2CDataOut 0
#define I2C_PORT (GPIOC)
#define I2CSCL (GPIO_PIN_7)
#define I2CSDA (GPIO_PIN_6)
//***************************************************************
// I2C Data input/output
// 0-Output, 1-Input
//***************************************************************
void I2CDataInOut(bool InOut)
{
if(InOut)
{
GPIO_Init(I2C_PORT,I2CSDA,GPIO_MODE_IN_FL_NO_IT);
}
else
{
GPIO_Init(I2C_PORT,I2CSDA,GPIO_MODE_OUT_OD_LOW_FAST);
}
}
//***************************************************************
// Send start condition
// ensure data is high then issue a start condition
// see also i2c_Start() macro
//***************************************************************
void I2C_Start (void)
{
GPIO_WriteHigh(I2C_PORT, I2CSDA);
_delay_5us(5);
GPIO_WriteHigh(I2C_PORT, I2CSCL);
_delay_5us(5);
GPIO_WriteLow(I2C_PORT, I2CSDA);
_delay_5us(5);
}
//***************************************************************
// Send stop condition
// data low-high while clock high
//***************************************************************
void I2C_Stop (void)
{
GPIO_WriteLow(I2C_PORT, I2CSDA);
_delay_5us(5);
GPIO_WriteHigh(I2C_PORT, I2CSCL);
_delay_5us(5);
GPIO_WriteHigh(I2C_PORT, I2CSDA);
}
//***************************************************************
//ROUTINE NAME : I2C_Ack
//INPUT/OUTPUT : None.
//DESCRIPTION : Acknoledge generation from now.
//COMMENTS : Transfer sequence = DATA, ACK.
//***************************************************************
void I2C_Rack(void)
{
GPIO_WriteLow(I2C_PORT, I2CSDA);
_delay_5us(5);
GPIO_WriteHigh(I2C_PORT, I2CSCL);
_delay_5us(5);
GPIO_WriteLow(I2C_PORT, I2CSCL);
_delay_5us(5);
}
//***************************************************************
//ROUTINE NAME : I2C_nAck
//INPUT/OUTPUT : None.
//DESCRIPTION : Non acknoledge generation from now.
//COMMENTS : Transfer sequence = DATA, NACK.
//***************************************************************
void I2C_nAck (void)
{
GPIO_WriteHigh(I2C_PORT, I2CSDA);
_delay_5us(5);
GPIO_WriteHigh(I2C_PORT, I2CSCL);
_delay_5us(5);
GPIO_WriteLow(I2C_PORT, I2CSCL);
_delay_5us(5);
}
//***************************************************************
// Send a byte to the slave 写一个数据没有应答
// return I2C_ERR OR I2C_CRR
//***************************************************************
bool SendByte(UCHAR I2cData)
{
UCHAR i;
bool I2CStatus;
for(i=0; i<8; i++)
{
GPIO_WriteLow(I2C_PORT, I2CSCL);
_delay_5us(5);
if(I2cData & 0x80)
{GPIO_WriteHigh(I2C_PORT, I2CSDA);}
else
{GPIO_WriteLow(I2C_PORT, I2CSDA);}
GPIO_WriteHigh(I2C_PORT, I2CSCL);
_delay_5us(5);
I2cData <<= 1;
}
GPIO_WriteLow(I2C_PORT, I2CSCL);
GPIO_WriteHigh(I2C_PORT, I2CSDA);//发送完一字节，接收应答
I2CDataInOut(I2CDataIn);
GPIO_WriteHigh(I2C_PORT, I2CSCL);
_delay_5us(5);
if(GPIO_ReadInputPin(I2C_PORT,I2CSDA) == 0)
{
I2CStatus = I2C_CRR;
}
else
{
I2CStatus = I2C_ERR;
}
I2CDataInOut(I2CDataOut);
return I2CStatus;
}
//***************************************************************
//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...
//***************************************************************
UCHAR RcvByte(void)
{
UCHAR i;
UCHAR ReadByte=0;
GPIO_WriteHigh(I2C_PORT, I2CSDA);
I2CDataInOut(I2CDataIn);
_delay_5us(10);
for(i=0; i<8; i++)
{
ReadByte <<= 1;
GPIO_WriteLow(I2C_PORT, I2CSCL);
_delay_5us(5);
GPIO_WriteHigh(I2C_PORT, I2CSCL);
_delay_5us(5);
if(GPIO_ReadInputPin(I2C_PORT,I2CSDA) == 1)
{ReadByte |= 0x01;}
_delay_5us(5);
}
GPIO_WriteLow(I2C_PORT, I2CSCL);
I2CDataInOut(I2CDataOut);
_delay_5us(10);
return ReadByte;
}
/*******************************************************
读N个数据，参数：
wrDAdr: write device-address 写器件地址
wordAdr: word address 读数据的寄存器地址
rdDAdr: read device-address 读器件地址
*pRdDat: p->read data 读数据指针
num: number 需要读数据的个数
*******************************************************/
bool I2C_Read(UCHAR wrDAdr,UCHAR wordAdr,UCHAR *pRdDat,UCHAR num)
{
bool I2CAck;
UCHAR i=0;
UCHAR rdDAdr;
rdDAdr = wrDAdr+1; //读器件地址为写地址加1
I2C_Start(); /*启动I2C*/
_delay_5us(5);
I2CAck = SendByte(wrDAdr); /*发写器件地址*/
if(!I2CAck)
{
return I2C_ERR;
}
I2CAck = SendByte(wordAdr); /*发寄存器地址*/
if(!I2CAck)
{
return I2C_ERR;
}
I2C_Start(); /*重启I2C*/
I2CAck = SendByte(rdDAdr); /*发读器件地址*/
if(!I2CAck)
{
return I2C_ERR;
}
_delay_5us(5);
for(i=0;i<num-1;i++)
{
*(pRdDat+i) = RcvByte();
I2C_Rack();
}
if(i==num-1)
{
*(pRdDat+i) = RcvByte();
I2C_nAck();
}
I2C_Stop();
return I2C_CRR;
}
/*******************************************************
写N个数据,前N-1个要应答,最后一个不要应答
wrDAdr: write device-address 写器件地址
wordAdr: word address 写数据的寄存器地址
*pWrDat: p->write data 写数据指针
num: number 需要写入的数据个数
*******************************************************/
bool I2C_Write(UCHAR wrDAdr,UCHAR wordAdr,UCHAR *pWrDat,UCHAR num)
{
bool I2CAck;
unsigned char i;
I2C_Start(); /*启动I2C*/
_delay_5us(5);
I2CAck = SendByte(wrDAdr); /*发写器件地址*/
if(!I2CAck)
{
return I2C_ERR;
}
I2CAck = SendByte(wordAdr); /*发要写的寄存器地址*/
if(!I2CAck)
{
return I2C_ERR;
}
for(i=0;i<num-1;i++)
{
I2CAck = SendByte(*(pWrDat+i));
if(!I2CAck)
{return I2C_ERR;}
}
if(i==num-1)
{
I2CAck = SendByte(*(pWrDat+num-1));
if(!I2CAck)
{return I2C_ERR;}
}
I2C_Stop();
return I2CAck;
}
以上代码不知为何读出数据不正确，用示波器看我发送的器件地址，寄存器地址这些都对，器件输出的数据是0xFF,程序中读出返回的数据是0x00,弄了一天没对相当郁闷，同志们指点下 |
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