This library provides routines for accessing microcontroller Flash memory. Note that prototypes differ for MCU to MCU due to the amount of Flash memory.

  Important :

• Due to the AVR family Flash specifics, Flash library is MCU dependent. Since some AVR MCU's have more or less than 64kb of Flash memory, prototypes may be different from chip to chip.
  Please refer to datasheet before using Flash library.
• When writting/erasing memory bear in mind that the memory is divided into pages; Size of the page is defined in the __FLASH_PAGE_SIZE constant (in program words) in the definition file of the appropriate MCU.
• Writing/erasing memory is possible only from the boot section of the Flash memory.

Library Routines

• FLASH_Read_Byte
• FLASH_Read_Bytes
• FLASH_Read_Word
• FLASH_Read_Words
• FLASH_Write_Page
• FLASH_Erase_Page

FLASH_Read_Byte

// for MCUs with Flash memory larger than 64kb
unsigned long tmp;
...
tmp = FLASH_Read_Byte(0x0D00);
...

FLASH_Read_Bytes

// for MCUs with Flash memory larger than 64kb
const long F_ADDRESS = 0x200;
unsigned int dat_buff[32];
...
FLASH_Read_Bytes(F_ADDRESS, dat_buff, 64);

FLASH_Read_Word

// for MCUs with Flash memory larger than 64kb
unsigned long tmp;
...
tmp = FLASH_Read_Word(0x0D00);
...

FLASH_Read_Words

// for MCUs with Flash memory larger than 64kb
const long F_ADDRESS = 0x200;
unsigned int dat_buff[32];
...
FLASH_Read_Words(F_ADDRESS, dat_buff, 32);

FLASH_Write_Page

unsigned int WRITE_ADDRESS = 0x200;
unsigned int dat_buff[8];
...
FLASH_Write_Page(WRITE_ADDRESS, dat_buff);

FLASH_Erase_Page

unsigned int ERASE_ADDRESS = 0x200;
...
FLASH_Erase_Page(ERASE_ADDRESS);

Library Example

The example demonstrates simple write to the Flash memory for AVR, then reads the data and displays it on PORTB, PORTC and PORTD.

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const long F_ADDRESS = 0x200;

const unsigned int data_[32] = {                               // constant table
  0x0000,0x0001,0x0002,0x0003,0x0004,0x0005,0x0006,0x0007,     //   in Flash at address F_ADDRESS
  0x0008,0x0009,0x000A,0x000B,0x000C,0x000D,0x000E,0x000F,
  0x0000,0x0100,0x0200,0x0300,0x0400,0x0500,0x0600,0x0700,
  0x0800,0x0900,0x0A00,0x0B00,0x0C00,0x0D00,0x0E00,0x0F00,
} absolute F_ADDRESS;

char i;
unsigned int word_;
unsigned int dat_buff[32];

void main() {
  DDRB = 0xFF;                                 // Set signal port as output
  DDRC = 0xFF;                                 // Set signal port as output
  DDRD = 0xFF;                                 // Set signal port as output
  word_ = data_[0];                            //  link const table

  PORTB = 1;                                   // signal program progress

  for (i = 0; i<64 ; i+=2) {                   // reading 32 words in loop
    word_ = FLASH_Read_Word(F_ADDRESS + i);    // demonstration of reading single word
    PORTD = word_;                             // output low byte to PORTD
    PORTC = word_ >> 8;                        // output high byte to PORTC
    Delay_ms(100);
  }

  PORTB = 2;                                   // signal program progress

  i = 0;                                       // initialize loop variable
  while ( i < 64 ) {                           // reading 64 bytes in loop
    PORTD = FLASH_Read_Byte(F_ADDRESS + i++);  // demonstration of reading single byte
    PORTC = FLASH_Read_Byte(F_ADDRESS + i++);  // demonstration of reading single byte
    Delay_ms(100);
  }

  PORTB = 3;                                   // signal program progress

  FLASH_Read_Bytes(F_ADDRESS, dat_buff, 64);   // demonstration of reading 64 bytes block
  for (i = 0; i<32 ; i++) {                    // use loop to display read block
    PORTD = dat_buff[i];                       // output low byte to PORTD
    PORTC = dat_buff[i] >> 8;                  // output high byte to PORTC
    Delay_ms(100);
  }
  
  PORTB = 4;                                   // signal program progress

  FLASH_Read_Words(F_ADDRESS, dat_buff, 32);   //  demonstration of reading 32 words block
  for (i = 0; i<32 ; i++) {                    // use loop to display read block
    PORTD = dat_buff[i];                       // output low byte to PORTD
    PORTC = dat_buff[i] >> 8;                  // output high byte to PORTC
    Delay_ms(100);
  }

}

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