I'd be tempted to suspect a bad solder joint (ie, the signal may not
be getting into the chip, only near it) and ground and power issues. 
Beyond that, have you matched the capacitors on the prototype closely
to the working version?  (value, voltage, ESR, composition)

I understand that these chips are rather sensitive to layout issues as
well.  Are you using the layout in the data sheet, or from a working
design?

Good luck!

-Adam

On 12/18/05, David Van Horn <dvanhorn@microbrix.com> wrote:
> > Divide and conquer:
> > Would it be possible to rebuild the factory system so the AVR is in a
> > socket, and you can swap in your AVR?  Or other means to swap in your
> > controller and program onthe the known good RF chip and cirquit?
>
> That's what I've done. The factory system is just the Nordic chip and
> ancillary components connected to a 20 pin header.  On that system, the
> code initializes the processor just fine, every time.
>
> On the prototypes, I get what the logic analyzer says is the same
> sequence and timing at the Nordic chip pins, but the Nordic chip fails
> to init.
>
> I am going through the factory board today to see if it actually matches
> the schematic given. Maybe there's something a little different that is
> causing it to work.
>
> This gets a bit more interesting, because due to layout constraints, I
> have the code set up to build for five different pinouts.
>
> Ignoring the factory board, I'm set up to talk to the 2.4Ghz chip in two
> versions, and the 915 MHz chip in two other versions. Each has slightly
> different pinouts into the AVR, and the two Nordic chips are so
> different you'd never guess they were made by the same people.  So, I
> abstracted all their functions to a layer of calls that the application
> layer uses, making both chips appear identical to the application.
>
> The code has a few equates that you set true or false, and it builds the
> right version.  That all seems fine, as I said the LA indicates that
> everything is coming out the right pins and ending up in the right
> places.
> If it's a code problem, then it's something that I'm not doing because
> the requirement isn't documented.
>
>
>
>
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