how can i correct this code??

-----Original Message-----
From: A...@yahoogroups.com [mailto:A...@yahoogroups.com] On Behalf Of sheikh adnan
Sent: Wednesday, July 13, 2005 5:07 AM
To: A...@yahoogroups.com
Subject: [AT91SAM7] how can i correct this code??

hi..

i m trying to write READ/ WRITE code for 24C64 with I2C standard, using 89c52, i m implementing my own I2C but having trouble with the code below that it does not read any charachter. here is the code for this written in KEIL micro vision..

#include <REG52.H>       // Header file for the 89C52 MCU
#include <STDIO.H>       // Standard I/O header file

//------
// Value Definitions
//------
#define  TRUE   0x01   // Value representing TRUE
#define  FALSE   0x00   // Value representing FALSE
#define  ON    0x01   // Value representing ON
#define  OFF    0x00   // Value representing OFF
#define  HIGH   1       // Value representing ON
#define  LOW    0       // Value representing OFF
#define   DELAY_BLINK  1500   // Value for delay time - blink

//------
// I/O Port Defines
//------
sbit   SDATA =  P1^0;     // Serial data
sbit   SCLK  =  P1^1;     // Serial clock

//------
// I2C Peripheral Function Prototypes
//------//------
// I2C Functions - Bit Banged
//------
void i2c_start (void);      // Sends I2C Start Trasfer
void i2c_stop (void);      // Sends I2C Stop Trasfer
void i2c_write (unsigned char input_data); // Writes data over the I2C bus
unsigned long i2c_read (void);    // Reads data from the I2C bus

//------
// Support Function Prototypes
//------

void initialize_system (void);
void delay_time (unsigned int time_end);    // To pause execution for pre-determined time
//------
// MAIN FUNCTION
//------
void main (void)
{
long  dum;
initialize_system ();

i2c_start();
//i2c_write('A');
//dum=  i2c_read();
i2c_read();
i2c_stop();

printf("%s",i2c_read()); 
}

//------
// I2C Functions - Bit Banged
//------

//------
//  Routine: i2c_start
// Inputs:  none
// Outputs: none
// Purpose: Sends I2C Start Trasfer
//------
void i2c_start (void){
 SDATA = HIGH;       // Set data line high
 SCLK = HIGH;       // Set clock line high
 SDATA = LOW;       // Set data line low (START SIGNAL)
 SCLK = LOW;        // Set clock line low
}

//------
//  Routine: i2c_stop
// Inputs:  none
// Outputs: none
// Purpose: Sends I2C Stop Trasfer
//------
void i2c_stop (void){
 unsigned char input_var;
 SCLK = LOW;        // Set clock line low
 SDATA = LOW;       // Set data line low
 SCLK = HIGH;       // Set clock line high
 SDATA = HIGH;       // Set data line high (STOP SIGNAL)
 input_var = SDATA;      // Put port pin into HiZ

 }

//------
//  Routine: i2c_write
// Inputs:  output byte
// Outputs: none
// Purpose: Writes data over the I2C bus
//------

/*void i2c_write(unsigned char output_data){
 unsigned char index;

 for(index = 0; index < 8; index++){   // Send 8 bits to the I2C Bus
                                   // Output the data bit to the I2C Bus
  SDATA = ((output_data & 0x80) ? 1 : 0);
       output_data  <<= 1;              // Shift the byte by one bit
  SCLK = HIGH;               // Clock the data into the I2C Bus
  SCLK = LOW;     
 }
 index = SDATA;       // Put data pin into read mode
 SCLK = HIGH;                // Clock the ACK from the I2C Bus
 SCLK = LOW;     
}
*/    
//------
//  Routine: i2c_read
// Inputs:  none
// Outputs: input byte
// Purpose: Reads data from the I2C bus
//------
unsigned long i2c_read (void)
{
 unsigned char index, input_data;

   index = SDATA;       // Put data pin into read mode
  
 input_data = 0x80;
 for(index = 0; index < 7; index++)   // Send 8 bits to the I2C Bus
 {
  input_data >>= 1;     // Shift the byte by one bit
  SCLK = HIGH;               // Clock the data into the I2C Bus
        input_data |= SDATA;       // Input the data from the I2C Bus
  SCLK = LOW;     
 }

 return 'A';
}
 
//------
// SUPPORT FUNCTIONS
// If wana initilize any thing then use this function
//------

void initialize_system (void)
{
   
    SCON  = 0x50;             // SCON: mode 1, 8-bit UART, enable rcvr
    TMOD |= 0x20;                  // TMOD: timer 1, mode 2, 8-bit reload  
    TH1   = -3;                    // TH1:  reload value for 9200 baud @ 11.0592MHz
    TR1   = 1;                     // TR1:  timer 1 run                         
    TI    = 0;                     // TI:   set TI to send first char of UART
 TI=1;
}

////////////////////////////////////////////////////////////////////////////////
//  Routine: delay_time
// Inputs:  counter value to stop delaying
// Outputs: none
// Purpose: To pause execution for pre-determined time
////////////////////////////////////////////////////////////////////////////////
/*
void delay_time (unsigned int time_end){
 unsigned int index;
 for (index = 0; index < time_end; index++);
}
*/

 

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