Re: [avrdude-dev] device signature string

[Michael Mayer]

On Fri, Dec 12, 2003 at 13:48:17 -0500, Brian Dean wrote:
> I kind've like the idea of auto detection, where applicable.  The
> STK500 is kind've special since you need to know certain part
> parameters to send to the STK500 before you can actually even enter
> programming mode in order to read the signature bytes.  However, it
> may be possible to tell the STK500 the part is any old chip, simply
> for the purposes of reading the signature bytes, then re-initialize
> the STK500 session using the actual part that we queried.

Doing it this way has first come to my mind to avoid the need to make some
structural changes. I rejected the idea, because the other way is more
strait forward. But if it is neccessary for the stk500 anyway, it may be an
interesting approach.


> About your implementation - I don't know any details about how you
> implemented it,

I'll send you a patch, if you like so. It's a hack and not clean for a
release, but you can see the way I did it.


> While in general, parts have only 1 possible
> signature value, I've seen several data sheets that have eratta
> stating that parts made before such and such a date have a different
> signature value than parts after that date.  Thus, we need to support
> a "list of signatures", that the current signature is compared
> against.

Strange. I added a single "long int signature" to struct avrpart. Using a
long and not a string is no problem here, because I read exactly three
bytes. Using a list here is easy.


> The YACC grammer for handling a list of values is also pretty trivial.

Yep. I love lex and yacc ;-)

  Michael