I've duplicated this issue very easily with NoDma, even with all the
previous fixes we've made.  The amount of debugging that Roman was able to
do - especially in tracking it down to that one particular while() loop in
Msp430spiNoDmaP - was very helpful.

I haven't confirmed this, but I suspect the problem is that the radio is
being shut off after the command that initiates the while() loop was given,
but before the while() loop got a chance to execute.  I'll verify and
implement some sort of fix.

-David



-----Original Message-----
From: Philip Levis [mailto:[EMAIL PROTECTED] 
Sent: Wednesday, March 14, 2007 8:10 PM
To: Jonathan Hui
Cc: [EMAIL PROTECTED]; David Moss; TinyOS Help (E-mail)
Subject: Re: [Tinyos-help] tinyos2 cc2420lpl locked-up node

On Mar 14, 2007, at 7:16 PM, Jonathan Hui wrote:

> Hi Roman,
>
> Thanks for discovering and looking into this problem. From the
> description you gave us, it does look like the radio is already
> disabled. My guess is that the radio stack is incorrectly trying to
> use the SPI bus or something else is calling SpiByte.write() when the
> resource is not correctly acquired. If the resource isn't acquired
> correctly, the SPI bus will not initialize correctly and you will
> definitely spin forever in that while-loop.
>
> Is it possible for you to figure out what is calling SpiByte.write()
> at the time of failure? You could either make the SpiByte interface
> parameterized just like SpiPacket, and see what client id is being
> passed in, or you could inspect the stack.

Good observation -- David observed the same behavior on the micaZ  
version of the stack, which also uses a direct (non-DMA) SPI bus, and  
introduced a temporary hack to the atmega128 SPI stack to prevent it.  
This came up in the core WG call today. Having additional information  
will help us figure out the bug: getting all of the last little nits  
out is one of the reasons why the stack was "experimental" in the 2.0  
release.

Phil


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