Well, i'm thinking about..when i tested the FlashBridge interface, i used a
mote connected to the programming board, and everything was perfect. And
without using the radio, so without send/receive interfaces. i only worked on
reading and writing some bytes in flash.Now there are problems with motes, and
i'm using batteries of 1.5 V, so 3V. So may be there is a conflict between
flash and radio.I will check by tests.
By the way, why does this kind of problem rise up only when i read from flash
and not also in the writing phase?It doesn't agree with the explanation of the
bus usage, right?
Daniele
-----Original Message-----
From: Philip Levis [mailto:[EMAIL PROTECTED]
Sent: Wed 9/20/2006 2:54 AM
To: David Moss
Cc: Munaretto, Daniel; [email protected]
Subject: Re: [Tinyos-help] repeating tests,no free memory
On Sep 19, 2006, at 3:17 PM, David Moss wrote:
> Are you accessing the Flash memory while using the radio? I
> believe I ran
> into some serious issues doing this with the MicaZ. The problem, I
> believe,
> is in the bus arbitration - because both the flash and the radio
> use the
> same SPI bus lines, if you're actively using flash and radio
> together on a
> micaz, the mote crashes.
>
That's interesting; I believe that the flash and CC2420 do not share
an SPI bus on the mica platforms.
> This doesn't happen with telos motes.
>
> I am about to start testing TinyOS 2.x to see if it still has this
> problem.
> I believe it shouldn't and doesn't because it has a better bus
> resource
> arbitration story. i.e. the radio has to request access to the bus
> before
> using it, and the flash has to request access before using it, etc.
Yes, this has been a major focus for 2.x. The bus on the Telos
platform is heavily overloaded (SPI to radio, SPI to flash, I2C for
sensors, UART, etc.) and so requires a lot of effort to abstract
properly in a way that's flexible and robust.
It turns out that this actually simplifies code in a lot of other
ways, though. For example, the radio stack actually has the receive
and transmit paths be separate users of the bus, which individually
arbitrate for it.
Phil
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