PIC: Example C language program to read and write 24LCxx series EEPROM

P IC : Example C language program to read and write 24LCxx series EEPROM

//*********************************************************  
//*            Using I2C Master Mode for aCCess Slave (EEPRM)  
//*                
//* Written by:  Richard Yang                                
//*              Sr. Corporate Application Engineer            
//*              MicroChip Technology Inc.                
//* Date:        Oct. 3nd '2002                            
//* Revision: 1.00 
//* Language tools : MPLAB-C18 v2.09.13 
//*      MPLINK v3.10
//*      MPLAB-IDE v6.00.17 & ICD2                                  
//***********************************************************
/* Include Header files  */

＃i nclude
＃i nclude   // Load I2C Header file from defult direct
＃i nclude
＃i nclude "P18LCD.h"  // Load P18LCD Header file form current working direct

/* Declare the Function Prototype */

void Initialize_I2C_Master(void);
void EE_Page_Write(unsigned char,unsigned char,unsigned char,unsigned char *);
void EE_SEQU_Read(unsigned char,unsigned char,unsigned char,unsigned char *);
void EEPROM_Write(unsigned char,unsigned char,unsigned char);
void EEPROM_ACK(unsigned char);
unsigned char EEPROM_Read(unsigned char,unsigned char);
void I2C_Done(void);
void Initialize_Timer2(void);
void isr_high_direct(void);
void isr_high(void);

#pragma romdata My_romdata=0x1000
const rom far unsigned char LCD_MSG1[]="SW2: Byte Write ";
const rom far unsigned char LCD_MSG2[]="SW6: Random Read";
const rom far unsigned char LCD_MSG3[]="Byte Write Mode ";
const rom far unsigned char LCD_MSG4[]="Random Read Mode";
const rom far unsigned char LCD_MSG5[]="Sended:        ";
const rom far unsigned char LCD_MSG6[]="Send:          ";
const rom unsigned char I2C_Write_Buffer[]="Microchip Technology";
#pragma romdata

/* Define following array in data memory */

unsigned char I2C_Read_Buffer [32];

/* define following variable in data memory at Access Bank */
#pragma udata access My_RAM
near unsigned char Debounce;
near unsigned char Send_Addr;
near unsigned char Send_Data;
near unsigned char Send_Length;
near unsigned char Read_Data;
near unsigned char P_SW2;
near unsigned char P_SW6;
#pragma udata

#define Page_Length 8
#define SW2  PORTAbits.RA4
#define SW6  PORTEbits.RE1
#define Bounce_Time 6
#define EE_CMD 0xA0

//***********************************************************
/*                */
/*      Main  Program        */
/*                */
//***********************************************************

void main(void)
{
 ADCON1=0b00000110;  // DISAble A/D Function
 TRISAbits.TRISA4=1;  // Set SW2 for input
 TRISEbits.TRISE1=1;  // Set SW6 for Input 
 Initialize_Timer2( );
 Initialize_I2C_Master( );
 OpenLCD( );
 
 if (SW2 & SW6)Debounce=0;
 else Debounce = Bounce_Time; 
 
 while(1)
 {
  LCD_Set_Cursor(0,0);    // Put LCD Cursor on (0,0)
  putrsLCD(LCD_MSG1); 
  LCD_Set_Cursor(1,0);    // Put LCD Cursor on (1,0)
  putrsLCD(LCD_MSG2);
 
  P_SW2=P_SW6=0; 
  Send_Addr=0;
  
  while(1)
  {
  if (P_SW2) 
  {
    P_SW2=0;
    Debounce = Bounce_Time;
    LCD_Set_Cursor(0,0);    // Put LCD Cursor on (0,0)
    putrsLCD(LCD_MSG3); 
    LCD_Set_Cursor(1,0);    // Put LCD Cursor on (0,0)
    putrsLCD(LCD_MSG5);
    
    do
    {
    while (!P_SW2);
    P_SW2=0;
    LCD_Set_Cursor(1,8);
    Send_Data=I2C_Write_Buffer[Send_Addr];
    EEPROM_Write(EE_CMD,Send_Addr,Send_Data);
    puthexLCD(EE_CMD);
    putcLCD(' ');
    puthexLCD(Send_Addr);
    putcLCD(' ');
    puthexLCD(Send_Data);
    EEPROM_ACK(EE_CMD);
    Send_Addr++;
    } while (I2C_Write_Buffer[Send_Addr]!=0x00);
  break;
  }
  
  if (P_SW6) 
  {
    P_SW6=0;
    Debounce = Bounce_Time;
    LCD_Set_Cursor(0,0);    // Put LCD Cursor on (0,0)
    putrsLCD(LCD_MSG4); 
    LCD_Set_Cursor(1,0);    // Put LCD Cursor on (0,0)
    putrsLCD(LCD_MSG6);
    
  
    while(1)
    {
    if (P_SW6)
    {
    P_SW6=0;
    LCD_Set_Cursor(1,5);
    Read_Data = EEPROM_Read(EE_CMD,Send_Addr);
    puthexLCD(EE_CMD);
    putcLCD(' ');
    puthexLCD(Send_Addr);
    putcLCD(' ');
    puthexLCD(EE_CMD);
    putcLCD(' ');
    puthexLCD(Read_Data);
    Send_Addr++;
    }
    if (P_SW2) break;
    }
    if (P_SW2) break;
  }
  if (P_SW2)
  {
    P_SW2=0;
    break;
  }
  } 
 }
}
//************************************************
//*      #pragma Interrupt Declarations        *
//*            *
//* Function: isr_high_direct                    *
//*  - Direct execution to the actual          *
//*    high-priority interrupt code.            *
//************************************************
#pragma code isrhighcode = 0x0008

void isr_high_direct(void) 
{          
    _asm      //begin in-line assembly
    goto isr_high  //go to isr_high function
    _endasm    //end in-line assembly
}

#pragma code

//************************************************
//* Function: isr_high(void)                     *     
//*   High priority interrupt for Timer2         *         
//************************************************
#pragma interrupt isr_high

void isr_high(void)
{
 PIR1bits.TMR2IF=0;     // Clear Timer2 interrupt Flag
 
 if (Debounce==0)
 {
  if (!SW2)
  { P_SW2=1; Debounce =Bounce_Time; } 
  if (!SW6) 
  { P_SW6=1; Debounce =Bounce_Time; } 
 }  
 else if (SW2 & SW6)Debounce--; 
   else Debounce =Bounce_Time;    
}        
#pragma code

//***********************************************
//*         Write a Byte to EEPROM               
//*   - CTRl : Control Byte of EEPROM    
//*   - addr : LOCation of EEPROM    
//*   - data : Data Byte of EEPROM     
//***********************************************

void Initialize_Timer2(void)
{

  RCONbits.IPEN=1;   // Enable Interrupt Priority bit
  IPR1bits.TMR2IP=1;   // Set Timer2 for High Priority
  INTCONbits.GIEH=1;   // Enable High Priority Interrupt

  OpenTimer2 (TIMER_INT_ON  // Turn On the Timer2 with Interrupt
       & T2_PS_1_4   // (4MHz/4) [4*10*(99+1)] = 4mS */
       & T2_POST_1_10);

  PR2 = 99;
}

//***********************************************
//*         Write a Byte to EEPROM              *
//*   - ctrl : Control Byte of EEPROM   *
//*   - addr : Location of EEPROM   *
//*   - data : Data Byte of EEPROM    *
//***********************************************
void EEPROM_Write(unsigned char ctrl,unsigned char addr,unsigned char data)
{
 IdleI2C();                // ensure module is idle
   StartI2C();      // Start condition
 I2C_Done();      // Wait Start condition completed and clear SSPIF flag   

 WriteI2C(ctrl);     // Write Control+Write to EEPROM & Check BF flag
 while(SSPCON2bits.ACKSTAT);  // wait until received the AcknowLEDge from EEPROM
 I2C_Done();      // Clear SSPIF flag

 WriteI2C(addr);     // Write Address to EEPROM
 while(SSPCON2bits.ACKSTAT);  // wait until received the Acknowledge from EEPROM
 I2C_Done();

 WriteI2C(data);     // Write Data to EEPROM
 while(SSPCON2bits.ACKSTAT);  // wait until received the Acknowledge from EEPROM
 I2C_Done();

 StopI2C();      // Stop condition
 I2C_Done();      // Wait the Stop condition completed
}

//***********************************************
//*         Pae Write to EEPROM                
//*
//*   - ctrl : Control Byte of EEPROM  
//*   - addr : Location of EEPROM    
//*   - length : Write counter
//*   - *dptr : RAM point --> EEPROM
//* 
//***********************************************
void EE_Page_Write(unsigned char ctrl,unsigned char addr,unsigned char length,unsigned char *dptr)
{
 IdleI2C();                // ensure module is idle
   StartI2C();      // Start condition
 I2C_Done();      // Wait Start condition completed
 
 WriteI2C(ctrl);     // Write Control+Write to EEPROM & Check BF flag
 while(SSPCON2bits.ACKSTAT);  // wait until received the Acknowledge from EEPROM
 I2C_Done();      // Clear SSPIF flag

 WriteI2C(addr);     // Write Address to EEPROM
 while(SSPCON2bits.ACKSTAT);  // wait until received the Acknowledge from EEPROM
 I2C_Done();

 while (length!=0)    // Check write completed ?
 {
  WriteI2C(*dptr);   // Write data to EEPROM
  while(SSPCON2bits.ACKSTAT); // wait until received the Acknowledge from EEPROM
  I2C_Done(); 
  dptr++;      // Point to next byte
  length--;
 }
 
 StopI2C();      // Stop condition
 I2C_Done();      // Wait the Stop condition completed
} 
 
//***********************************************
//*         EEPROM Acknowledge Polling          *
//*   --  The routine will polling the ACK  *
//*       response from EEPROM       *
//*   --  ACK=0 return        *
//*   --  ACK=1 send Restart & loop check  *
//***********************************************
void EEPROM_ACK(unsigned char ctrl)
{
 unsigned char i;

 IdleI2C();                // ensure module is idle
   StartI2C();      // Start condition
 I2C_Done();      // Wait Start condition completed

 WriteI2C(ctrl);     // Write Control to EEPROM (WRITE)
 I2C_Done();      // Clear SSPIF flag

 while (SSPCON2bits.ACKSTAT)  // test for Acknowledge from EEPROM
    {
  for (i=0;i<100;i++);  // Delay for next Repet-Start

       RestartI2C();               // initiate Repet-Start condition
  I2C_Done();          // Wait Repet-Start condition completed

  WriteI2C(ctrl);    // Write Control to EEPROM (WRITE)
  I2C_Done();      // Clear SSPIF flag 
    }   
 StopI2C();                      // send STOP condition
 I2C_Done();      // wait until stop condition is over 
}

//***********************************************
//*    Random Read a Byte from EEPROM           *
//*   - ctrl : Control Byte of EEPROM (Write) *
//*     (Ctrl +1 ) : Read Command    *
//*   - addr : Address Byte of EEPROM   *
//*   - Return : Read Data from EEPROM   *
//***********************************************
unsigned char EEPROM_Read(unsigned char ctrl,unsigned char addr)
{
 unsigned char f;
 
 IdleI2C();                // ensure module is idle
   StartI2C();      // Start condition
 I2C_Done();      // Wait Start condition completed

 WriteI2C(ctrl);     // Write Control to EEPROM    
    while(SSPCON2bits.ACKSTAT);    // test for ACK condition, if received
 I2C_Done();      // Clear SSPIF flag

 WriteI2C(addr);     // Write Address to EEPROM         
    while(SSPCON2bits.ACKSTAT);   // test for ACK condition, if received  
 I2C_Done();      // Clear SSPIF flag

    RestartI2C();                // initiate Restart condition
 I2C_Done();

 WriteI2C(ctrl+1);    // Write Control to EEPROM              
 while(SSPCON2bits.ACKSTAT);    // test for ACK condition, if received
 I2C_Done();      // Clear SSPIF flag

 f=ReadI2C();     // Enable I2C Receiver & wait BF=1 until received data
 I2C_Done();      // Clear SSPIF flag

 NotAckI2C();     // Genarate Non_Acknowledge to EEPROM
 I2C_Done();    
                     
    StopI2C();                   // send STOP condition
 I2C_Done();      // wait until stop condition is over

 return(f);      // Return Data from EEPROM 
}

//***********************************************
//*         Sequential Read from EEPROM                
//*
//*   - ctrl : Control Byte of EEPROM  
//*   - addr : Location of EEPROM    
//*   - length : Read counter
//*   - *dptr : Store EEPROM data to RAM

//* 
//***********************************************
void EE_SEQU_Read(unsigned char CTRl,unsigned char addr,unsigned char length,unsigned char *dptr)
{
 IdleI2C();                // ensure module is idle
   StartI2C();      // Start condition
 I2C_Done();      // Wait Start condition completed

 WriteI2C(ctrl);     // Write Control to EEPROM    
    while(SSPCON2bits.ACKSTAT);    // test for ACK condition, if received
 I2C_Done();      // Clear SSPIF flag

 WriteI2C(addr);     // Write Address to EEPROM         
    while(SSPCON2bits.ACKSTAT);   // test for ACK condition, if received  
 I2C_Done();      // Clear SSPIF flag

    RestartI2C();                // initiate Restart condition
 I2C_Done();

 WriteI2C(ctrl+1);    // Write Control to EEPROM              
 while(SSPCON2bits.ACKSTAT);    // Test for ACK condition, if received
 I2C_Done();      // Clear SSPIF flag

 while (length!=0)
 {
  *dptr=ReadI2C();   // Enable I2C Receiver & Store EEPROM data to Point buffer 
  I2C_Done(); 
  dptr++; 
  length--;
    
  if (length==0) NotAckI2C();
  else AckI2C();    // Continue read next data, send a acknowLEDge to EEPROM
  
  I2C_Done();
 }

    StopI2C();                   // send STOP condition
 I2C_Done();      // wait until stop condition is over 
}

//***********************************************
//*   Check I2C action that is completed        *
//***********************************************
void I2C_Done(void)
{
 while (!PIR1bits.SSPIF);  // Completed the action when the SSPIF is Hi.
 PIR1bits.SSPIF=0;      // Clear SSPIF
}

//************************************************
//* Initial I2C Master Mode with 7 bits Address  *
//* CLOCk Speed : 100KHz @4MHz      *
//************************************************
void Initialize_I2C_Master(void)
{
 OpenI2C(MASTER,SLEW_ON);
 SSPADD= 9;
}