123.c

使用S3C44B0 IIC控制器实现串行EEPROM存储器24C16的数据存储和访问。

#include <string.h>
#include "G:\44b0\44b.h"
#include "G:\44b0\44blib.h"
#include "G:\44b0\def.h"
#include "G:\44b0\iic.h"

#define WRDATA	    (1)
#define POLLACK     (2)
#define RDDATA	    (3)
#define SETRDADDR   (4)

#define IICBUFSIZE 0x20

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

void __irq IicInt(void);

void Wr24C16(U32 slvAddr,U32 addr,U8 data)
{
    _iicMode=WRDATA;
    _iicPt=0;
    _iicData[0]=(U8)addr;
    _iicData[1]=data;
    _iicDataCount=2;
    
    rIICDS=slvAddr;//0xa0  选中24C16 IICADD用来存放CPU的7位从器件地址
    rIICSTAT=0xf0; //MasTx,Start  IICSTAT寄存器主要用来设置I2C总线的工作模式及工作状态控制                                     启动发送 
    //Clearing the pending bit isn't needed because the pending bit has been cleared.
    while(_iicDataCount!=-1);       //等待中断

    _iicMode=POLLACK;

    while(1)
    {
	rIICDS=slvAddr;//选中24C16 
	_iicStatus=0x100;                     					                                      
	rIICSTAT=0xf0; //MasTx,Start 启动发送
	rIICCON=0xaf;  //resumes IIC operation. IICCON寄存器主要用来设置应答信号使能及发送                                                 时钟频率等
	while(_iicStatus==0x100);
	if(!(_iicStatus&0x1))    //对ACK进行了判断
	    break; // when ACK is received      成功接收到 ACK
    }
    rIICSTAT=0xd0;  //stop MasTx condition 
    rIICCON=0xaf;   //resumes IIC operation. 
    Delay(1);	    //wait until stop condtion is in effect.

    //write is completed.
}
	

void Rd24C16(U32 slvAddr,U32 addr,U8 *data)
{
    _iicMode=SETRDADDR;
    _iicPt=0;
    _iicData[0]=(U8)addr;
    _iicDataCount=1;

    rIICDS=slvAddr;
    rIICSTAT=0xf0; //MasTx,Start  
    //Clearing the pending bit isn't needed because the pending bit has been cleared.
    while(_iicDataCount!=-1);

    _iicMode=RDDATA;

    _iicPt=0;
    _iicDataCount=1;
    
    rIICDS=slvAddr;
    rIICSTAT=0xb0; //MasRx,Start
    rIICCON=0xaf;  //resumes IIC operation.   
    while(_iicDataCount!=-1);

    *data=_iicData[1];
}

void __irq IicInt(void)
{
    U32 iicSt,i;
    rI_ISPC=BIT_IIC;

    iicSt=rIICSTAT; 
    if(iicSt&0x8){} // when bus arbitration is failed.
    if(iicSt&0x4){} // when a slave address is matched with IICADD
    if(iicSt&0x2){} // when a slave address is 0000000b
    if(iicSt&0x1){} // when ACK isn't received

    switch(_iicMode)
    {
	case POLLACK:
	    _iicStatus=iicSt;
	    break;

	case RDDATA:
	    if((_iicDataCount--)==0)
	    {
		_iicData[_iicPt++]=rIICDS;
	    
		rIICSTAT=0x90;  //stop MasRx condition 
		rIICCON=0xaf;   //resumes IIC operation.
		Delay(1);	//wait until stop condtion is in effect.
				//too long time... 
		//The pending bit will not be set after issuing stop condition.
		break;    
	    }	     
	    _iicData[_iicPt++]=rIICDS;
				//The last data has to be read with no ack.
	    if((_iicDataCount)==0)
		rIICCON=0x2f;	//resumes IIC operation with NOACK.  
	    else 
		rIICCON=0xaf;	//resumes IIC operation with ACK
	    break;

	case WRDATA:
	    if((_iicDataCount--)==0)
	    {
		rIICSTAT=0xd0;	//stop MasTx condition 
		rIICCON=0xaf;	//resumes IIC operation.
		Delay(1);	//wait until stop condtion is in effect.
		//The pending bit will not be set after issuing stop condition.
		break;    
	    }
	    rIICDS=_iicData[_iicPt++];  //_iicData[0] has dummy.
	    for(i=0;i<10;i++);	    //for setup time until rising edge of IICSCL
	    rIICCON=0xaf;	    //resumes IIC operation.
	    break;

	case SETRDADDR:
	    //Uart_Printf("[S%d]",_iicDataCount);
	    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=0xaf;	    //resumes IIC operation.
	    break;

	default:
	    break;	  
    }
}