Hello all,
i had some trouble with the serial number of an ATMEGA4808. I had three different devices. Two of them had a prefix as expected starting with 30 43 47 47 44 51. Then i had a third device, where the Serialnumber (SERNUM0-SERNUM9) where set to something different. converting this string to ASCII led to 'unknown' as you can see in the attached image. I think this might have been an errror in production. Does anyone had this issue before?
Thanks for any help.
I think this might have been an errror in production.
That is very unlikely. It is FAR more likely that you made an errror, in reading, converting, etc.
Perhaps you are the victim of a clone or counterfeit chip. What are you hoping to do with this information, anyhow?
Do the chips properly run whatever app code you want?
You would need to show a complete schematic of your setup, including power sources, filter capacitors, programming connections and serial number decoding and corresponding display app to get more advice.
Hi avrcandies,
thanks for the fast reply.
I was just wondering because we inspected this Serial Number "unknow". We also debugged this and saw this serial number written to the SIGROW (preprogrammed).
Yes code runs properly, but we use the serial number for identification issues. Therefore we were sceptical when receiving Serial number unknown.
Then i had a third device, where the Serialnumber (SERNUM0-SERNUM9) where set to something different.
Are you 100% sure you know what all the valid ranges could be? There is probably a list somewhere, maybe the datasheet is not the most complete list (or maybe it is).
Hi avrcandies,
I am not 100% sure about the valid range. But what i know from the datasheet is, that the serial number is stored in SIGROW (which is a preprogrammed register and could not be altered) and has a length of 10 byte[SERNUM0 to SERNUM9].
I was only little confused, that two devices had very similar unique IDs (both started with 30 43 47 47 44 51 ... ) and the third device having a completely different unique ID, which then translates to ASCII "unknow...".
Thus, I wanted some feedback, if anyone had similar issues or maybe this was only a coincidence that the Unique ID translates to "unknow...".
Where did you purchase the UNKOWN chip from?
or maybe this was only a coincidence that the Unique ID translates to "unknow...".
I would rule this out, as well as any error you might have made in reading the serial number. The probability that any error would spell out "unknow" followed by a 0 string delimiter is just too low, especially when you seem to be able to correctly read other chips. So that chip seems very fishy to me.
mrono Here's an older case of 'unknow'
https://www.avrfreaks.net/comment/1100836#comment-1100836
Nice work!
