Re: [avr-libc-dev] atmega324 variants (P, A, PA) signature

[rr]

Joerg Wunsch wrote:
> As rr wrote:
>
> > Actual datasheet is mega324a/mega324pa. Here the signature bytes are
> > different: mega324a: 0x1E9515 and mega324pa:0x1e9511.
>
> I've checked the XML files here, and there's one thing what I really
> think is a bug:
>
>     <SIGNATURE>
>       <ADDR000>$1E</ADDR000>
>       <ADDR001>$95</ADDR001>
>       <ADDR002>$08</ADDR002>
>     </SIGNATURE>
>     <SIGNATURE>
>       <ADDR000>$1E</ADDR000>
>       <ADDR001>$95</ADDR001>
>       <ADDR002>$11</ADDR002>
>     </SIGNATURE>
>
> This is from the ATmega324P.xml file.  Clearly, there's some
> controversy in that. ;-)  I'm not sure whether my XML file is from the
> most recent version of AVR Studio (I'm not an AVR Studio user myself),
> can you please check that against your versions, and if this is still
> in the files, send a bug report to <address@hidden>?

Sorry, but I'm using linux, so I can't help you about AVR Studio.
> The other ATmega324* derivatives have 1E 95 08 for for the ATmega324,
> and 1E 95 11 for the ATmega324PA.
>
> > I've searched for avr-libc manual on web and on pdf, but they are from 
> > 2009 and of course are a little bit outdated.
>
> Sorry, I have to update it after the recent release.  I didn't manage
> it before leaving for vacation.
>
> > So, can I assume there is no support for mega324a, since there is no
> > signature compatibility?
>
> There's no difference from a library point of view anyway.
Then, why only mega324a and mega324pa have different signature bytes?
mega162a/mega162pa and all other Flash size variants from the same 
datasheet have both the same signature bytes.

> > Where can I get a summarized information about the differences between
> > mega324p and mega324pa other than looking throughout the datasheet?
>
> I thought there's an appnote epxlaining the transition to the "A"
> devices, isn't there?
Yes, of course! Sorry, I meant mega324a and mega324pa.
From what I searched on the datasheet of atmega324a/atmega324pa, the 
differences are: electrical characteristics and only PA has some 
functions to disable hardware parts in order to reduce power consumption.