iic.c

s3c44b0三星提供的读写eeprom的代码要使用中断,而且会在中断内延时,会影响cpu的响应速度。这个源码是不用中断的s3c44b0读写eeprom方法。

#include "inc\44b0x.h"
#include "DataType.h"
#include "main.h"
#include "iic.h"

#define IICBUFSIZE 150


U8 _iicData[IICBUFSIZE];
volatile int _iicDataCount;
int _iicPt;


void vIicInit(void)
{
	rPCONF |= 0xa; //PF0:IICSCL, PF1:IICSDA
	rPUPF |= 0x3; //pull-up disable
	//pISR_IIC = (unsigned)IicInt;
	//rINTMSK &= ~(BIT_IIC);
	rIICCON = (1<<7)|(0<<6)|(1<<5)|(0xe);
	//Enable interrupt, IICCLK=MCLK/16, Enable ACK
	//48Mhz/16/(14+1)=200kHz
	rIICADD=0x10; // S3C44B0X slave address
	rIICSTAT=0x10;
}




uchar ucWr24C512(U32 slvAddr,U32 addr,U8 p_ucLen,U8 *data)
{
	U8 i;
	U32 j;
	
	_iicPt=0;
	_iicData[0]=(U8)(addr/256);
	_iicData[1]=(U8)(addr%256);
	copydata(&_iicData[2], data, p_ucLen);
	_iicDataCount = p_ucLen+2;
	rIICDS=slvAddr;//0xa0
	rIICSTAT=0xf0; //MasTx,Start
	//Clearing the pending bit isn't needed because the pending bit has been cleared.
	while(1)
	{
		j = 0;
		while(0 == (rIICCON&0x10))
		{
			Feed_WatchDog();
			j++;
			if (10000 <= j) // time out
			{
				return FAIL;
			}
		}
		if((_iicDataCount--)==0)
		{
			rIICSTAT=0xd0; //stop MasTx condition
			rIICCON=0xae; //resumes IIC operation.
			for (j=0; j<1200; j++) // 12ms, wait until write in eeprom finish
			{
				vDelay10us();
			}
			break;
		}
		rIICDS=_iicData[_iicPt++]; //_iicData[0] has dummy.
		for(i=0;i<10;i++); //for setup time until rising edge of IICSCL
		rIICCON=0xae; //resumes IIC operation.
	}
	return SUCCESS;
	//write is completed.
}




uchar ucRd24C512(U32 slvAddr,U32 addr,U8 p_ucLen,U8 *data)
{
	U8 i;
	U32 j;
	
	_iicPt=0;
	_iicData[0]=(U8)(addr/256);
	_iicData[1]=(U8)(addr%256);
	_iicDataCount=2;
	rIICDS=slvAddr;
	rIICSTAT=0xf0; //MasTx,Start
	//Clearing the pending bit isn't needed because the pending bit has been cleared.
	while(1)
	{
		j = 0;
		while(0 == (rIICCON&0x10))
		{
			Feed_WatchDog();
			j++;
			if (10000 <= j) // time out
			{
				return FAIL;
			}
		}
		if((_iicDataCount--)==0)
		{
			break; //IIC operation is stopped because of IICCON[4]
		}
		rIICDS=_iicData[_iicPt++];
		for(i=0;i<10;i++); //for setup time until rising edge of IICSCL
		rIICCON=0xae; //resumes IIC operation.
	}
	_iicPt=0;
	_iicDataCount=p_ucLen;
	rIICDS=slvAddr;
	rIICSTAT=0xb0; //MasRx,Start
	rIICCON=0xae; //resumes IIC operation.
	while(1)
	{
		j = 0;
		while(0 == (rIICCON&0x10))
		{
			Feed_WatchDog();
			j++;
			if (10000 <= j) // time out
			{
				return FAIL;
			}
		}
		if((_iicDataCount--)==0)
		{
			_iicData[_iicPt++]=rIICDS;
			rIICSTAT=0x90; //stop MasRx condition
			rIICCON=0xae; //resumes IIC operation
			for (j=0; j<200; j++) // 2ms, wait until stop condtion is in effect.
			{
				vDelay10us();
			}
			break;
		}
		_iicData[_iicPt++]=rIICDS;
		//The last data has to be read with no ack.
		if((_iicDataCount)==0)
			rIICCON=0x2e; //resumes IIC operation with NOACK.
		else
			rIICCON=0xae; //resumes IIC operation with ACK
	}
	copydata(data, &_iicData[1], p_ucLen);
	return SUCCESS;
}