通用MSP430—I2C程序

//==================================//

//通用MSP430—I2C程序

//收藏：清风徐徐

//QQ：78779514

//EMAIL：XSL88888@TOM.com

//2004.2.4

//===================================//

#include \"MSP430x14x.h\"

//P3.2 SCL

//P3.3 SDA

#define SDA_1 P3OUT |= BIT3 //SDA = 1

#define SDA_0 P3OUT &=~ BIT3 //SDA = 0

#define SCL_1 P3OUT |= BIT2 //SCL = 1

#define SCL_0 P3OUT &=~ BIT2 //SCL = 0

#define DIR_IN P3DIR &=~ BIT3; SDA_1 //I/O口为输入

#define DIR_OUT P3DIR |= BIT3 //I/0口为输出

#define SDA_IN ((P3IN >> 3) & 0x01) unsigned int a[50];

static void Delay(unsigned int n)

{

unsigned int i;

for (i=0; i}

void Init(void)

{

SCL_1;

//Read SDA

Delay(5);

SDA_1;

Delay(5);

}

void Start(void)

{

SDA_1;

Delay(5);

SCL_1;

Delay(5);

SDA_0;

Delay(5);

SCL_0;

Delay(5);

}

void Stop(void)

{

SDA_0;

Delay(5);

SCL_1;

Delay(5);

SDA_1;

Delay(5);

}

void WriteByte(unsigned char WriteData)

{

unsigned char i;

for (i=0; i<8; i++)

{

SCL_0;

Delay(5);

if (((WriteData >> 7) & 0x01) == 0x01)

{

SDA_1;

}

else

{

SDA_0;

}

Delay(5);

SCL_1;

WriteData = WriteData << 1;

Delay(5);

}

SCL_0;

SDA_1;

Delay(5);

Delay(5);

}

unsigned char ReadByte(void)

{

unsigned char i;

unsigned char TempBit = 0;

unsigned char TempData = 0;

SCL_0;

Delay(5);

SDA_1;

for (i=0; i<8; i++)

{

Delay(5);

SCL_1;

Delay(5);

DIR_IN;

if (SDA_IN == 0x01 /*sda==1*/)

{

TempBit = 1;

}

else

{

TempBit = 0;

}

DIR_OUT;

TempData = (TempData << 1) | TempBit;

SCL_0;

}

Delay(5);

return(TempData);

}

void ReceiveAck(void)

{

unsigned char i = 0;

SCL_1;

Delay(5);

DIR_IN;

while ((SDA_IN == 0x01 /*sda==1*/) && (i < 255)/*调试方便,可以不要*/)

{

i++;

}

DIR_OUT;

SCL_0;

Delay(5);

}

void Acknowledge(void)

{

SCL_0;

Delay(5);

DIR_OUT;

SDA_0;

SCL_1;

Delay(5);

SCL_0;

}

unsigned int ReadWord(unsigned char unit/*address*/)

{

unsigned char HighData = 0;

unsigned char LowData = 0;

unsigned int TempData = 0;

Start();

WriteByte(0xa0);

ReceiveAck();

WriteByte(unit);

ReceiveAck();

Start();

WriteByte(0xa1);

ReceiveAck();

LowData = ReadByte();

Acknowledge();

HighData = ReadByte();

Stop();

TempData = (HighData << 8) + LowData;

Delay(1000);

return(TempData);

}

void ReadWords(unsigned char unit/*address*/)

{

unsigned char i;

unsigned char HighData = 0;

unsigned char LowData = 0;

unsigned int TempData = 0;

Start();

WriteByte(0xa0);

ReceiveAck();

WriteByte(unit);

ReceiveAck();

Start();

WriteByte(0xa1);

ReceiveAck();

for (i=0; i<49; i++)

{

LowData = ReadByte();

Acknowledge();

HighData = ReadByte();

Acknowledge();

a[i]= (HighData << 8) + LowData;

}

LowData = ReadByte();

Acknowledge();

HighData = ReadByte();

Stop();

a[49] = (HighData << 8) + LowData;

Delay(1000);

}

void WriteWord(unsigned char unit/*address*/, unsigned int WriteData)

{

unsigned char LowData = 0;

unsigned char HighData = 0;

LowData = (unsigned char)WriteData;

HighData = (unsigned char)(WriteData >> 8);

Start();

WriteByte(0xa0);

ReceiveAck();

WriteByte(unit);

ReceiveAck();

WriteByte(LowData);

ReceiveAck();

WriteByte(HighData);

ReceiveAck();

Stop();

Delay(2000);

}