flash using UART

[niteesh]

#define F_CPU 1000000

#include <avr/io.h>

#include <util/delay.h>

#include <avr/boot.h>

#include <inttypes.h>

#include <avr/interrupt.h>

#include <avr/pgmspace.h>

#include <stdio.h>

 

 

//////////////////////////////////////////////////////////////////////////////////////

 

#define BAUD 4800UL

 

#define MY_UBRR ((F_CPU/ (16UL * BAUD))-1)

 

void usart_init()

{

 

UBRRH = MY_UBRR>>8;

UBRRL = MY_UBRR;

 

UCSRB = (1<<RXEN)|(1<<TXEN);

 

UCSRC = (1<<URSEL)|(1<<UCSZ1)|(1<<UCSZ0);

 

  }

 

void usart_write(unsigned char data)

{

 

while(!(UCSRA & (1<<UDRE)));

 

UDR = data;

 

  }

 

unsigned char usart_read()

{

 

while(!(UCSRA &(1<<RXC)));

 

return UDR;

 

}

 

void usart_string(unsigned char *str)

{

 

unsigned char i = 0;

 

while(str != '')

{

  while(!(UCSRA & (1<<UDRE)));

  UDR = str;

  i++;

 }

 

 

}

//////////////////////////////////////////////////

 

int main ( void )

{int j=120;

uint16_t i;

unsigned char *A;

uint8_t sreg;

uint32_t page = 0;

unsigned char *buf = *A;

unsigned char ch;

usart_init();

DDRB|=(1<<PB0)|(1<<PB1)|(1<<PB7);

PORTB|=(1<<PB0);

ch=usart_read();

if(ch=='X')

{

PORTB|=(1<<PB1);

 

asm("jmp 0x0000");}

 

if(ch=='P') // yes if host wants to program

{usart_write('o'); //ack

// storing the bytes from ith location of flash memory to ith variable of array A//

 

for(i=0;i<15000;i++)

{

A=usart_read();

if(A=='X')              // Check for ESC

{PORTB|=(1<<PB7);

goto SPM;} // jump to application programmed at 0x0000

 

}

 

// storing the bytes from ith location of flash memory to ith variable of array A//

}

 

//================================= SPM =========================================/

       

SPM:   

while(1)

{

//=========================================================================/

if(j)

{

 

sreg = SREG;

cli(); // Disable interrupts.

eeprom_busy_wait ();

boot_page_erase (page);

boot_spm_busy_wait ();      // Wait until the memory is erased.

 

for (i=0; i<SPM_PAGESIZE; i+=2)

{

    // Set up little-endian word.

  uint16_t w = *buf++;

   w += (*buf++) << 8;

 

   boot_page_fill (page + i, w);

}

boot_page_write (page);     // Store buffer in flash page.

boot_spm_busy_wait();      // Wait until the memory is written.

boot_rww_enable ();

SREG = sreg;

}

else

{

asm ( "jmp 0x0000" );

}

 

j–;

page = page + 128;

//=============================================================================/

}

}

 

 

 

 

 

this is my code for programing flash using UART.

its not working plz help.

'P' is programming flash & 'X' for exit from bootloading section.

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