eeprom native library

Projects Programming
1

Hello
Today I was using the eeprom using the native library of avrlibc #include <avr/eeprom.h>
The function in documentation is:

uint8_t eeprom_read_byte 	( 	const uint8_t *  	__p	) 	
Read one byte from EEPROM address __p.

it return a byte and needs as argument a pointer to an adress
So far so good, my problem starts now when I use the function passing the address of the position.

int adress = 0;//I want position 0
int readValue = eeprom_read_byte(&i);//It wount work as expected don´t understand why
int readValue = eeprom_read_byte((uint8_t *)i);//Doing a cast work's well but why ?
2

The eeprom_read_byte() function expects an address. You defined one. But, what the heck is i?

You are reading a byte, and storing it in an int. Why?

3

Sorry my mistake typing
Here is the correct one:

uint8_t adress = 0;//I want position 0
uint8_t readValue = eeprom_read_byte(&adress);//It wount work as expected don´t understand why
uint8_t readValue = eeprom_read_byte((uint8_t *)adress);//Doing a cast work's well but why ?
5

I may have had a similar question recently, see it this thread is of any help:

6

With the ampersand you are giving it the address of the variable adress and that isn't 0.

But the function expect an address!!
I cannot pass the variable

7

But the function expect an address!!

But not the address of the variable that holds the address. Making that function take a pointer was probably not the brightest move. But, you know how to pass it what it wants, so quit worrying about why that works. Just accept that it does.

8

But not the address of the variable that holds the address

Uhmm I was thinking that passing the address of the variable was in fact making the functions "looks" to the value 0 which was the eeprom address I want.
Perhaps you are right, time to move on and just use the cast.