MSP430模拟IIC接口程序_MSP430单片机_微控实验网！51单片机AVR单片机教程站 www.mcusy.cn

MSP430模拟IIC接口程序

发布时间：2009/7/27 阅读次数：969 字体大小: 【小】【中】【大】

1-简介
MSP430单片机普通II模拟IIC接口程序范例。

2-程序例程

#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) //Read SDA

unsigned int a[50];

//*****************************************************

static void Delay(unsigned int n)
{
unsigned int i;
for (i=0; i }
void Init(void)
{
SCL_1;
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);
}
//******************************************************************************

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