ATXMEGA32A4U-AU wrong signature bytes, wrong chip

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Just got hold of an ATXMEGA32A4U-AU as I want to run the High Res. Extension at x8.

Problem is that the STK600 reports the chip as an ATXMEGA32A4 not AU. The chip works fine when programmed as an 'A' at x4 high res extension, but when asked to do x8, it does not work. Thus the chip ID bytes report it is not an AU but an A and it works like an A.

As the chip is sold by a reputable distributor and marked as an ATXMEGA32A4U-AU, has anyone got any explanation?

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Yes, but you'll have to do a bit of leg work to fully appreciate it.

What do you expect the signature bytes to be for a 32A4U (Section 7.3.4, production signature row)? And what are they (the ones causing the STK600 to report a 32A4)?

Jeff Nichols

Last Edited: Thu. Oct 25, 2012 - 01:27 PM
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A reputable distributor got screwed? It does happen.

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Afraid I did not note the incorrect ID reported in red by the STK600. After programming and running it as a '4A', I sent it back to the distributor.

You indicated that you have an explanation - can you share it?

Thanks

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Yeah, the 32A4 and 32A4U have the same signature, so a STK600 can't tell them apart.

I don't know why this was overlooked by Atmel, but as I'm sure you'll agree it's a problem.

Jeff Nichols

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This is odd as the STK600 drop down processor selector has entries for both the 32A4U and 32A4, and as the 32A4 keeps it happy and the 32A4U does not,the id code in the STK600 must be different for the respective chips? Are you saying that the STK600 software is incorrect?

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The datasheets claim they are the same. Maybe the STK600 has a way of identifying them beyond the id.

Jeff Nichols

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I just checked with a 32A4U on a custom board and my AVR One doesn't complain if I check the signature against either a 32A4 or a 32A4U in the drop down box (Atmel Studio 6 device programming window). I don't have an STK600 to test.

Jeff Nichols

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Have you ever got the high res extension (to the AWeX) to run at x8? for the 32A4U