网上关于philips的32位ARM微控制器经过I2C接口读写AT24C系列E2PROM的比如根本都是经过中止方法读写的，包含周建功的书上也是用中止方法的，用这种方法，要在中止服务程序中进行杂乱的处理，程序比较难以了解，运用非中止方法编程比较便利，便于了解。以下程序本人在LPC2364上测试经过。程序中的一些常量做了扼要阐明，详细课检查LPC23xx系列微控制器的用户手册。
I2C.h
#define AT24C64NW 0xA0
#define AT24C64NR 0xA1
#define MAX_TIMEOUT0x00FFFFFF
#define I2CONSET_I2EN0x00000040 /* I2C Control Set Register */
#define I2CONSET_AA0x00000004
#define I2CONSET_SI0x00000008
#define I2CONSET_STO0x00000010
#define I2CONSET_STA0x00000020
#define I2CONCLR_AAC0x00000004 /* I2C Control clear Register */
#define I2CONCLR_SIC0x00000008
#define I2CONCLR_STAC0x00000020
#define I2CONCLR_I2ENC0x00000040
#define I2DAT_I2C0x00000000 /* I2C Data Reg */
#define I2ADR_I2C0x00000000 /* I2C Slave Address Reg */
#define I2SCLH_SCLH0x00000080 /* I2C SCL Duty Cycle High Reg */
#define I2SCLL_SCLL0x00000080 /* I2C SCL Duty Cycle Low Reg */
#define SDA0 0x08000000 //p0.27
#define SCL0 0x10000000 //p0.28
#define SDA0CON 0x08000000
#define SCL0CON 0x10000000
extern DWORD I2CInit( UINT32 Fi2c );
extern DWORD I2CStart( void );
extern DWORD I2CStop( void );
extern DWORD I2CStartAgain( void );
extern DWORD I2C_ReadByte(BYTE ACK, BYTE *RcvData);
extern DWORD I2C_SendNByte(UINT16 SubAddr ,UINT8 *Data,UINT8 Length);
extern DWORD I2C_ReadNByte(UINT16 SubAddr ,UINT8 *Data,UINT8 Length);
I2C.c
DWORD I2CInit( UINT32 Fi2c )
{
if (Fi2c > 400000)
Fi2c = 400000;
PINSEL1 &= ~0x03C00000;
PINSEL1 |= 0x01400000;/* set PIO0.27 and PIO0.28 to I2C0 SDA and SCK */
I20SCLH = (Fpclk/Fi2c + 1) / 2;/*设定I2C时钟*/
I20SCLL = (Fpclk/Fi2c)/2;
I20CONCLR = 0x2C;// clear STA, SI,AA
I20CONSET = 0x40;// SET I2EN/*使能主I2C */
return( TRUE );
}
DWORD I2CStart( void )
{
DWORD timeout = 0;
DWORD returnValue = FALSE;
/*— Issue a start condition —*/
I20CONCLR=I2CONCLR_SIC|I2CONCLR_AAC|I2CONCLR_STAC;
I20CONSET=I2CONSET_STA|I2CONSET_I2EN;/* Set Start flag */
/*— Wait until START transmitted —*/
while( 1 )
{
if (I20STAT==0x08)
{
returnValue = TRUE;
break;
}
if ( timeout >= MAX_TIMEOUT )
{
returnValue = FALSE;
break;
}
timeout++;
}
return( returnValue );
}
DWORD I2CStartAgain( void )
{
DWORD timeout = 0;
DWORD returnValue = FALSE;
/*— Issue a start condition —*/
I20CONCLR = I2CONCLR_SIC|I2CONCLR_AAC|I2CONCLR_STAC;//发送重复开始条件前一定要清零SI
I20CONSET = I2CONSET_STA|I2CONSET_I2EN;/* Set Start flag */
/*— Wait until START transmitted —*/
while( 1 )
{
if ( I20STAT == 0x10 )
{
returnValue = TRUE;
break;
}
if ( timeout >= MAX_TIMEOUT )
{
returnValue = FALSE;
break;
}
timeout++;
}
return( returnValue );
}
DWORD I2CStop( void )
{
I20CONSET = I2CONSET_STO;/* Set Stop flag */
I20CONCLR = I2CONCLR_SIC|I2CONCLR_STAC|I2CONCLR_AAC;/* Clear SI flag */// modified
/*— Wait for STOP detected —*/
while( I20CONSET & I2CONSET_STO );
return TRUE;
}
void I2C_SendByte(UINT8 SData)
{
I20DAT=SData;
I20CONCLR =0x28;/*清零SI,STA */
while (!(I20CONSET&I2CONCLR_SIC));// wait interrupt flag ( waiting for SI==1)
}
DWORD I2C_SendNByte(UINT16 SubAddr ,UINT8 *Data,UINT8 Length)
{
BYTE i;
I2CStart();
if(I20STAT==0x08)/*已发送开始条件*/
{
I2C_SendByte(AT24C64NW);// Device Address
if(I20STAT==0x18) /*已发送SLA+W，已接纳ACK */
{
I2C_SendByte((SubAddr>>8)&(0x00FF));
if(I20STAT==0x28)/*已发送SubAddr_H，已接纳ACK */
{
I2C_SendByte(SubAddr&(0x00FF));
if(I20STAT==0x28) /*已发送SubAddr_L，已接纳ACK */
{
for(i=0;i { do{ I2C_SendByte(Data[i]); }while(I20STAT!=0x28); }
if(I2CStop())
{
DelayNS(5);//10ms
return TRUE;
}
return FALSE;
}
return FALSE;
}
return FALSE;
}
return FALSE;
}
return FALSE;
}
DWORD I2C_ReadByte(BYTE ACK, BYTE *RcvData)
{
if (ACK==1)//send ACK
{
I20CONSET=I2CONSET_AA;
}
else//sendNOACK
if(ACK==0)
{
I20CONCLR=I2CONCLR_AAC;
}
I20CONCLR=I2CONCLR_SIC|I2CONCLR_STAC;// clear SISAT
while (!(I20CONSET&I2CONCLR_SIC));// wait interrupt flag ( waiting for SI==1)
if(ACK==1)
{
if((I20STAT&0xF8)==0x50) //receive data and get ack
{
*RcvData=I20DAT;
return TRUE;
}
else
return FALSE ;
}
else
if(ACK==0)
{
if((I20STAT&0xF8)==0x58) //receive data and get NoAck (the last data you want to get)
{
*RcvData=I20DAT;
return TRUE;
}
else
return FALSE ;
}
return FALSE ;
}
DWORD I2C_ReadNByte(UINT16 SubAddr ,UINT8 *Data,UINT8 Length)
{
BYTEi;
if (!I2CStart())
{
return FALSE;
}
if(I20STAT==0x08)/*已发送开始条件*/
{
I2C_SendByte(AT24C64NW);// Device Address
if(I20STAT==0x18) /*已发送SLA+W，已接纳ACK */
{
I2C_SendByte((SubAddr>>8)&(0x00FF));
if(I20STAT==0x28)/*已发送SubAddr_H，已接纳ACK */
{
I2C_SendByte(SubAddr&(0x00FF));
if(I20STAT==0x28) /*已发送SubAddr_L，已接纳ACK */
{
if (I2CStartAgain())//发送重复开始条件切换为主承受形式
{
I2C_SendByte(AT24C64NR);
if(I20STAT==0x40)/*已发送SLA+R，已接纳ACK*/
{
for(i=0;i { if(!(I2C_ReadByte(1,&Data[i]))) { return FALSE; } } if( !( I2C_ReadByte(0, &Data[Length-1]) ) ) //读最终一个数据 { return FALSE; } if (I2CStop())//发送中止条件 { return TRUE; } return FALSE; } return FALSE; } return FALSE; } return FALSE; } return FALSE; } return FALSE; } return FALSE; }
