Well i want to ask if i want to set some numbers in eeprom.how much time can be stored.Let me become more clear.If arduino goes off how much time has to pass in order the eeprom to loose the numbers?
Also does reset or software deletes eeprom?
What can delete epprom except a program that writes zeros.
And a last one if i try to read eeprom at an adress that i have never writen anything could this have trash inside or it will give 0 or Null?
I saw that you write a byte. how can i write and read an double?
if i want to set some numbers in eeprom.how much time can be stored.
Years.
Let me become more clear.If arduino goes off how much time has to pass in order the eeprom to loose the numbers?
Years.
Also does reset or software deletes eeprom?
Uploading a sketch will not erase the EEPROM. Burning a fresh bootloader will erase the EEPROM.
if i try to read eeprom at a spot that i have never writen anything could this have trash inside or it will give 0 or Null?
EEPROM erases to all 1's: 0xFF (=255).
I have edited my previous post probably after you wrote your answer. So i think i have to make a function that can write a double to eeprom and read it also?this is not included in the library
A number written will last years, until it is erased or overwritten.
There is a fuse bit that saves eeprom contents thru a chip erase. Normal reset will not impact eeprom contents. See section 28 of the datasheet.
A never written to address will read back as 0xFF or 255.
A double is 4 bytes, so break up your number as you write it. There is an eeprom library that may do that for your already.
well i can not find any library that works in general and not too complicated.eppromex has error when opened in eclipse. i can not find eppromAnything. can you give me a link of any library?
kyrpav:
well i can not find any library that works in general and not too complicated.eppromex has error when opened in eclipse. i can not find eppromAnything. can you give me a link of any library?
well ok i saw that but i do not want to make a struct in order to save 2 doubles at EEPROM. it is too much.
kyrpav:
well ok i saw that but i do not want to make a struct in order to save 2 doubles at EEPROM. it is too much.
Are you running out of memory? The float value used 4 bytes and you can only write to EEPROM one byte at a time so you have to break down the float into separate bytes to store it.
well now 2 different post goes to the same problem.Anyway one question remains.i have a double that has 7 digits since it is 4 byte when i print it and ask to print more than 7 digits i get a number slightly different.
What i am concerned is if this happens only at Serial.print. I i try to use the number to calculation will it give the wrong number or the correct?
What i am concerned is if this happens only at Serial.print. I i try to use the number to calculation will it give the wrong number or the correct?
If you don't believe/like the answers you get in the other 14 threads you've started/butted into, what makes you think you'll like the answer you get here?
It's time you quit tap dancing (you aren't all that good at it) and posted some code with some real questions.
who said i do not like or agree with the answers?I just mentioned that i started this topic to ask about the safeness of the data at eeprom and another to ask about saving a double and a certain problem that i had. I said only that at this topic the conversation change a lit bit and was prety close to the other topic.
There is not bad opinion or rude behaviour from my side so you do not need to attack.I appreciate your help and the help i get from the forum.