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calibration byte for programming atmega-8L

Thread starter #1
please I am beginner ..
when I want to program the atmega-8L on the programmer ,the message apeares , it requires the calibration byte .
what is the byte calibration and what is its value.
thanks again.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
#2
Presumably it's similar to the calibration word in small PIC's?, as such it's stored inside the chip, placed there during testing at the factory. Your programmer 'should' automatically read and restore the calibration byte as you erase or write the chip - it's actual value will vary depending on the specific chip, that's why it's called a 'calibration' byte.

The datasheet for the device should tell you where it's stored, for PIC's it's the highest word in program memory.
 
Thread starter #3
thnk you
but the message which apeares when I program atmega-8 by the programmer ,don't apeare on when I program Pic (e.g pic16f..)
 

Nigel Goodwin

Super Moderator
Most Helpful Member
#4
kasser said:
thnk you
but the message which apeares when I program atmega-8 by the programmer ,don't apeare on when I program Pic (e.g pic16f..)
Depends if you use a PIC that has a calibration byte?, such as the 12F675, and it might save and restore it without even telling you.

But like I said before, read the datasheet for the chip, and see where it's stored - if you've already wiped it, then you need to find some way of recalibrating it.
 
#5
Are you refering to the signature byte? The calibration byte is not required for programming, perhaps you're refering to the signature byte? In which case your programmer is telling you you've set it up to program the wrong type of device. What hardware and software are you using for programming ? On the AVR series the configuration bytes are read only as they're OTP fuses tripped during manufactoring, I've heard of a few issolated cases of these fuses becoming corrupted but it is extremely rare.
 
#6
This is the third time I've seen you post this question. Was the answer you received yesterday on avrfreaks lacking in some aspect?

[edit]Should we believe that your $1500 programmer came without instructions?[/edit]
 
Last edited:
#9
Have you looked through the ATmega8 Data Sheet? There should be section on calibration of the internal clock, and pretty much anything else. I've only done Attiny13L and Attiny2313L, haven't calibrated anything. Believe there is an Appnote on the Atmel website concerning this as well.
 

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