#include<reg51.h>
#include"Config.h"
#include"IOCfg.c"
#include"TimeDLY.h"
#include"IIC_PCA8574.h"

//IC起始信號(hào)：
void StartIIC(void)
{
	IIC_SDA = 1;
	nNop(20);
	IIC_SCL = 1;
	nNop(20);
	IIC_SDA = 0;
	nNop(20);
	IIC_SCL = 0;
	//nNop(50);
	}

//IIC停止信號(hào)：
void StopIIC(void)
{
	IIC_SDA = 0;
	nNop(20);
	IIC_SCL = 1;
	nNop(20);
	IIC_SDA = 1;
	nNop(50);
	}

//讀取從機(jī)應(yīng)答信號(hào)函數(shù)：
bit GetACK(void)
{
	bit ack;
	IIC_SDA = 1;
	IIC_SCL = 1;
	nNop(50);
	ack = IIC_SDA;
	IIC_SCL = 0;
	nNop(50);
	return(ack);
	}

//向IIC總線發(fā)出應(yīng)答信號(hào)函數(shù)：
void PutACK(bit ack)
{
	IIC_SDA = ack;
	IIC_SCL = 1;
	nNop(50);
	IIC_SCL = 0;
	nNop(50);
	}

//初始化IIC總線函數(shù)：
void InitIIC(void)
{
	IIC_SCL = 1;
	nNop(10);
	IIC_SDA = 1;
	nNop(50);
	}

//功能向IIC總線寫一字節(jié)數(shù)據(jù)函數(shù)：
void IIC_WriteByte(INT8U temp)
{
	INT8U i;
	for(i=0;i<8;i++)
	{
		IIC_SDA = (bit)(temp & 0x80);
		temp = temp << 1;
		nNop(20);
		IIC_SCL = 1;
		nNop(20);
		IIC_SCL = 0;
		//nNop(50);
		}
	}

//從IIC總線讀一字節(jié)數(shù)據(jù)函數(shù)：
INT8U IIC_ReadByte(void)
{
	INT8U i;
	INT8U temp;
	IIC_SDA = 1;
	for(i=0;i<8;i++)
	{
		temp = temp << 1;
		IIC_SCL = 1;
		while(IIC_SDA) temp++;
		IIC_SCL = 0;
		nNop(20);
		}
	return(temp);
	}

//向PCA8574寫一字節(jié)數(shù)據(jù)函數(shù)：
bit PCA8574_PutOne(INT8U SlaveAddr,INT8U dat)
{
	//確保從機(jī)地址最低位是0
	SlaveAddr &= 0xfe;
	
	//啟動(dòng)I2C總線
	StartIIC();
	
	//發(fā)送數(shù)據(jù)
	IIC_WriteByte(dat);
	if ( GetACK() )
	{
		StopIIC();
		return 1;
		}

	//發(fā)送完畢，停止I2C總線，返回
	StopIIC();
	return 0;
	}
	
//從PCA8574讀一字節(jié)數(shù)據(jù)函數(shù)：
bit PCA8574_GetOne(INT8U SlaveAddr,INT8U dat)
{
	while(IIC_INT!=0);
	SlaveAddr |= 0x01;
	
	//啟動(dòng)I2C總線
	StartIIC();
	
	//發(fā)送從機(jī)地址
	IIC_WriteByte(SlaveAddr);
	if ( GetACK() )
	{
		StopIIC();
		return 1;
		}
	
	//接收數(shù)據(jù)
	dat = IIC_ReadByte();
	PutACK(1);
	
	//接收完畢，停止I2C總線，返回
	StopIIC();
	return 0;
	}