Re: [avr-gcc-list] read write eeprom WINAVR20050214

[Royce & Sharal Pereira]

Hi,

On Sat, 19 Feb 2005 09:05:40 +0700, andi  
<address@hidden> wrote:
> i declare variable in eeprom like this:
>
> unsigned char Eeprom_Value __attribute__ ((section(".eeprom"))) = 30;
>
> and when i read and write :
> eeprom_read_byte((unsigned)&Eeprom_Value);
> eeprom_write_byte((unsigned)&Eeprom_Value);
---------------------------------------------
GCC has no idea of different address spaces. So your '&' option will not  
work here.
Even if it did, your 'write' function is missing the byte to be written.

Here's what I do:
//Define eeprom addresses :-
enum {BYTE1_AD, BYTE2_AD, WORD1_AD, WORD2_AD=WORD1_AD+2};

char x,y;       int w,z;

//now call the functions in your code...
//Read..
y = eeprom_read_byte(BYTE1_AD);
z = eeprom_read_word(WORD1_AD);

//write..
eeprom_write_byte(BYTE1_AD, x);
eeprom_write_word(WORD2_AD, y);

BTW have you gone thru the avrlibc docs? If you had you would have found  
the answers to many of your recent queries. Please do so now. It will save  
you time & frustration (wait till you try putting strings / arrays in  
flash or defining pointers in flash.... :) ).


--Royce.

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