[SOLVED] How can I save a 16bit data in 8bit EEPROM?

Mithun_K_Das · Sep 19, 2012

can anyone tell me How can I save a 16bit data in 8bit EEPROM?

bigdogguru · Sep 19, 2012

I would recommend writing two routines, a 16-bit write routine and 16-bit read routine.

The 16-bit write routine simply writes the LSB and MSB into consecutive EEPROM addresses starting at the address passed to the routine.

The 16-bit read routine simply reads the LSB and MSB from consecutive EEPROM addresses starting at the address passed to the routine.

Of course, you must decide on either a little endian or big endian method of storage.

For which microcontroller are you implementing these routines?

Also is the C Compiler, MikroC?

BigDog

Mithun_K_Das · Sep 19, 2012

I'm using PIC16f690. with microC compiler. can you give any example in C?

internetuser2k12 · Sep 20, 2012

This is an example of writing a 4 byte int to eeperom. Hope this helps. You can use just Lo and Hi for 2 bytes. http://www.mikroe.com/forum/viewtopic.php?f=147&t=48450

Mithun_K_Das · Sep 20, 2012

Thanks for your link.

Mithun_K_Das · Sep 25, 2012

Hi, I tried the code with modification. But it shows error that Lo, Hi ... are undeclared. here is the screed shot.

internetuser2k12 · Sep 25, 2012

Add these lines at the top of the code.

Code:

#define Lo(param) ((char *)&param)[0]
#define Hi(param) ((char *)&param)[1]
#define Higher(param) ((char *)&param)[2]
#define Highest(param) ((char *)&param)[3]

Mithun_K_Das · Sep 25, 2012

Thank you for your help. I've modified the program as follows:

Code:

#define Lo(param) ((char *)&param)[0]
#define Hi(param) ((char *)&param)[1]
#define Higher(param) ((char *)&param)[2]
#define Highest(param) ((char *)&param)[3]

unsigned short eeprom_intenal_address, eeprom_external_address, lowByte, highByte, higherByte, highestByte;
unsigned long int myInt, eeprom_integer_value, askvalue = 10000;
char StrEEPROM[23], StrmyInt[23];

void EEPROM_Write(unsigned short eeprom_internal_address, unsigned long int eeprom_integer_value);
void EEPROM_Read(unsigned short eeprom_internal_address);

void EEPROMWriteInt(unsigned short eeprom_internal_address, unsigned long int eeprom_integer_value) {
        lowByte = Lo(eeprom_integer_value);
        highByte = Hi(eeprom_integer_value);
        higherByte = Higher(eeprom_integer_value);
        highestByte = Highest(eeprom_integer_value);

        EEPROM_write(eeprom_internal_address, lowByte);
        eeprom_internal_address++;
        delay_ms(20);
        EEPROM_write(eeprom_internal_address, highByte);
        eeprom_internal_address++;
        delay_ms(20);
        EEPROM_write(eeprom_internal_address, higherByte);
        eeprom_internal_address++;
        delay_ms(20);
        EEPROM_write(eeprom_internal_address, highestByte);
        eeprom_internal_address++;
        delay_ms(20);

        lowByte = 0x00;
        highByte = 0x00;
        higherByte = 0x00;
        highestByte = 0x00;

}

unsigned long int EEPROMReadInt(unsigned short eeprom_internal_address)
        {
        Lo(eeprom_integer_value) = EEPROM_read(eeprom_internal_address);
        eeprom_internal_address++;
        delay_ms(20);
        Hi(eeprom_integer_value) = EEPROM_read(eeprom_internal_address);
        eeprom_internal_address++;
        delay_ms(20);
        Higher(eeprom_integer_value) = EEPROM_read(eeprom_internal_address);
        eeprom_internal_address++;
        delay_ms(20);
        Highest(eeprom_integer_value) = EEPROM_read(eeprom_internal_address);
        eeprom_internal_address++;
        delay_ms(20);

        return eeprom_integer_value;

}


void display()
{
  ch = (tlong / 10000) % 10;
  //Lcd_Out(1,3,"Tmp");
  Lcd_Out(1,3,ROMtext_to_RAMtext(text2));
  Lcd_Chr_Cp(48+ch);          // Write result in ASCII format
  ch = (tlong / 1000) % 10;
  Lcd_Chr_Cp(48+ch);          // Write result in ASCII format
  ch = (tlong / 100) % 10;
  Lcd_Chr_Cp(48+ch);          // Write result in ASCII format
  Lcd_Chr_CP('.');
  ch = (tlong / 10) % 10;     // Extract hundreds of millivolts
  Lcd_Chr_CP(48+ch);           // Write result in ASCII format
  ch = (tlong / 1) % 10;      // Extract tens of millivolts
  Lcd_Chr_CP(48+ch);           // Write result in ASCII format
  Lcd_Chr_Cp(223);
  Lcd_Chr_CP('F');
  Lcd_Chr_CP(' ');
  Delay_ms(20);
}




while(RD0_bit == 0 || RD1_bit == 0)  // key function for asking value
  {
   RA5_bit = 1;
   Delay_ms(300);
   RA5_bit = 0;
   top:
       while(RD0_bit == 0)
       {
        askvalue++;
        
        eeprom_external_address = 0x00;
        eeprom_integer_value = 0;
        EEPROMWriteInt(eeprom_external_address, askvalue);
        eeprom_external_address = eeprom_external_address + 4;
        
        RA5_bit = 1;
        Delay_ms(50);
        RA5_bit = 0;
        break;
       }
       while(RD1_bit == 0)
       {
        askvalue++;

        eeprom_external_address = 0x00;
        eeprom_integer_value = 0;
        EEPROMWriteInt(eeprom_external_address, askvalue);
        eeprom_external_address = eeprom_external_address + 4;
        
        
        RA5_bit = 1;
        Delay_ms(50);
        RA5_bit = 0;
        break;
       }
        
        eeprom_external_address = 0x00;
        askvalue = EEPROMReadInt(eeprom_external_address);
        eeprom_external_address = eeprom_external_address + 4;
       value = askvalue;
       tlong =  value;
       setvalue = value; // getting the asking value here
       display();
  }

Here, I want to show the value of "askvalue". Thank you again. Solved

[SOLVED] How can I save a 16bit data in 8bit EEPROM?

Mithun_K_Das

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