LPC23xx reads and writes AT24C64 via I2C interface-EEWORLD

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The examples on the Internet about reading and writing AT24C series E2PROM through I2C interface of Philips 32-bit ARM microcontroller are basically read and written through interrupt mode, including Zhou Ligong's book. In this way, complex processing must be performed in the interrupt service program, and the program is difficult to understand. It is more convenient to program in non-interrupt mode and easy to understand. The following program has been tested on LPC2364. Some constants in the program are briefly explained. For details, please refer to the user manual of LPC23xx series microcontrollers.

I2C.h

#define AT24C64NW 0xA0
#define AT24C64NR 0xA1

#define MAX_TIMEOUT 0x00FFFFFF
#define I2CONSET_I2EN 0x00000040 /* I2C Control Set Register */
#define I2CONSET_AA 0x00000004
#define I2CONSET_SI 0x00000008
#define I2CONSET_STO 0x00000010
#define I2CONSET_STA 0x 00000020

#define I2CONCLR_AAC 0x00000004 /* I2C Control clear Register */
#define I2CONCLR_SIC 0x00000008
#define I2CONCLR_STAC 0x00000020
#define I2CONCLR_I2ENC 0x00000040

#define I2DAT_I2C 0x00000000 /* I2C Data Reg */
#define I2ADR_I2C 0x00000000 /* I2C Slave Address Reg */
#define I2SCLH_SCLH 0x00000080 /* I2C SCL Duty Cycle High Reg */
#define I2SCLL_SCLL 0x00000080 /* 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 I2CS top( 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; /* Set I2C clock */

I20SCLL = (Fpclk/Fi2c)/2;

I20CONCLR = 0x2C;//clear STA, SI,AA

I20CONSET = 0x40; // SET I2EN /* Enable master 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; // Be sure to clear SI before sending a repeated start condition

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; /* Clear 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) /* Start condition has been sent */

{

I2C_SendByte(AT24C64NW); // Device Address

if(I20STAT==0x18) /* SLA+W has been sent, ACK has been received */

{

I2C_SendByte((SubAddr>>8)&(0x00FF));

if(I20STAT==0x28) /* SubAddr_H has been sent, ACK has been received */

{

I2C_SendByte(SubAddr&(0x00FF));

if(I20STAT==0x28) /* SubAddr_L has been sent, ACK has been received */

{

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 // send NOACK

if(ACK==0)

{

I20CONCLR=I2CONCLR_AAC;

}

I20CONCLR=I2CONCLR_SIC|I2CONCLR_STAC; // clear SI SAT

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)

{

BYTE i;

if (!I2CStart())

{

return FALSE;

}

if(I20STAT==0x08) /* Start condition has been sent */

{

I2C_SendByte(AT24C64NW); // Device Address

if(I20STAT==0x18) /* SLA+W has been sent, ACK has been received */

{

I2C_SendByte((SubAddr>>8)&(0x00FF));

if(I20STAT==0x28) /* SubAddr_H has been sent, ACK has been received */

{

I2C_SendByte(SubAddr&(0x00FF));

if(I20STAT==0x28) /* SubAddr_L has been sent, ACK has been received */

{

if (I2CStartAgain()) //Send repeated start condition to switch to master receiving mode

{

I2C_SendByte(AT24C64NR);

if(I20STAT==0x40)/*SLA+R sent, ACK received*/

{

for(i=0;i

{

if(!(I2C_ReadByte(1,&Data[i])))

{

return FALSE;

}

if( !( I2C_ReadByte(0, &Data[Length-1]) ) ) //Read the last data

{

return FALSE;

}

if (I2CStop()) //Send stop condition

{

return TRUE;

}

return FALSE;

}

return FALSE;

}

return FALSE;

}

return FALSE;

}

return FALSE;

}

return FALSE;

}

return FALSE;

}

Keywords：LPC23xx Reference address：LPC23xx reads and writes AT24C64 via I2C interface

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