i2c.c

病理冰冻切片机C51程序,KEIL C编译环境

#include "mqb.h"
extern BYTE WaitWriteTime;

bit ClockI2C(void)
{
	bit sample;
	MEMCLK=1;
	_nop_();
	sample=MEMDATA;
	MEMCLK=0;
	_nop_();
	return(sample);
}
void AnswerI2C(void)
{
	MEMDATA=0;
	ClockI2C();
	MEMDATA=1;
}
void NoAnswerI2C(void)
{
	MEMDATA=1;
	ClockI2C();
}


void InitI2C(void)
{
	MEMDATA=0;
	MEMDATA=0;_nop_();
	MEMCLK=1; _nop_();
	MEMDATA=1;_nop_();
}
void StartI2C(void)
{
	MEMCLK=1; _nop_();
	MEMDATA=0;_nop_();
	MEMCLK=0; _nop_();
}
void StopI2C(void)
{	
	MEMDATA=0;_nop_();
	MEMCLK=1; _nop_();
	MEMDATA=1;_nop_();
}

BYTE ReadI2C(void)
{
	BYTE ch=0;
	BYTE i=0x80;
	while (i)
	{
		if (ClockI2C()) ch=ch|i;
		i=i>>1;	
	}
	return ch;
}

bit  WriteI2C(BYTE ch)
{
	BYTE i=8;
	while (i--)
	{
			
		MEMDATA=ch&0x80;
		ClockI2C();
		ch=ch<<1;
	}
	MEMDATA=1;
	return 0;
}


BYTE  RdI2CByte(BYTE addr)
{
BYTE ch;
	StartI2C();
	if (!WriteI2C(0xa0)) {StopI2C();return 0xff;}
	if (!WriteI2C(addr)) {StopI2C();return 0xff;}
	StopI2C();
	StartI2C();
	if (!WriteI2C(0xa1)) {StopI2C();return 0xff;}
        ch=ReadI2C();
        NoAnswerI2C();	
	return ch;
}


bit  WrI2CByte(BYTE addr,BYTE ch)
{
	while (WaitWriteTime)
	{
	}
	StartI2C();
	if (WriteI2C(0xa0))
	{
		WriteI2C(addr);
		WriteI2C(ch);
		StopI2C();
		WaitWriteTime=1;
		return TRUE;
	}
	StopI2C();
	return FALSE;
}