[Tinyos-devel] RE: SPI issue for CC2420 stack

[David Moss]

Hui -

 

Although there may still be issues with Msp430SpiNoDmaP, the CC2420 stack
SPI issues were solved separately:

 

1.	Added/used state information inside of components like
CC2420TransmitP and CC2420ReceiveP so we know if SpiPacket.received() is
valid when it is signaled.
2.	When the power is cut to the CC2420, the SPI bus is not cancelled /
turned off / cut / etc.  Instead.
3.	The microcontroller continues to drive the SPI bus as the master, so
it clocks in garbage.
4.	When the microcontroller completes its SPI bus operation, the CC2420
driver ignores the SpiPacket.received() signal due to (1) - the CC2420 knows
it's already off and any SPI bus information returned is garbage.


So the SPI bus isn't actually messed with since it's the microcontroller
driving the operation, and it's up to the CC2420 to know if the received()
event is valid.

 

-David

 

 

 

 

 

  _____  

From: Hui Cao [mailto:chbone at gmail.com] 
Sent: Wednesday, August 01, 2007 9:46 AM
To: 'David Moss'
Subject: RE: SPI issue for CC2420 stack

 

David,

 

Thanks. Can you provide me some details about how it is solved in the new
version? Since I also encounter the similar bugs in the last version, I had
thought that we should change the Msp430SpiNoDmaP.nc file.

 

Best,

 

                           Hui

 

  _____  

From: David Moss [mailto:dmm at rincon.com] 
Sent: Wednesday, August 01, 2007 11:22 AM
To: caohu at cse.ohio-state.edu
Subject: RE: SPI issue for CC2420 stack

 

Hi Hui,

 

Yes, the bug has been resolved in 2.0.2.

 

 

  _____  

From: Hui Cao [mailto:chbone at gmail.com] 
Sent: Monday, July 30, 2007 5:21 AM
To: 'David Moss'
Subject: SPI issue for CC2420 stack

 

Hi, David,
 
I wonder whether this bug has been resolved in the new 2.0.2 version.
 
"LPL Lockups when the node is also accessing the USART.  This is a SPI bus
issue, where shutting off the SPI bus in the middle of an operation may
cause the node to hang.  Look to future versions on CVS for the fix."
 
Best,
                Hui

 

 

  _____  

From: tinyos-devel-bounces at Millennium.Berkeley.EDU
[mailto:tinyos-devel-bounces at Millennium.Berkeley.EDU] On Behalf Of David
Moss
Sent: Tuesday, July 03, 2007 8:48 PM
To: tinyos-devel at Millennium.Berkeley.EDU
Subject: [Tinyos-devel] 2.0.2 CC2420

 

Just updated the CC2420 stack in preparation for 2.0.2.  The file
architecture has been re-arranged a little bit, making it easier to see how
the stack is put together.  As a result, the .platform files that reference
the cc2420 were updated.  

 

Test results are included. Let me know if you have any issues.

-David

 

 

Recent Updates (from the readme):

* New chip SPI bus arbitration working with Receive and Transmit.

 

* Applied TUnit automated unit testing to CC2420 development

  > Caught lots of bugs, especially through regression testing

  > Source code in tinyos-2.x-contribs/tunit/

 

* Applied TEP115 behavior to CC2420 SplitControl in Csma and Lpl

 

* Updated ActiveMessageAddressC to provide the ActiveMessageAddress
interface

  > Updated CC2420ConfigP to handle ActiveMessageAddress.addressChanged()
and

    sync automatically upon address change events.

 

* Updated CC2420Config interface to enable/disable sw/hw acknowledgements

 

* Updated CC2420ConfigP to share register editing through single functions

 

* Acknowledge after packet length and FCF check out valid.  

  > The destination address is confirmed in hardware, so we don't need 

    to download the entire header before acking.

 

* Moved the getHeader() and getMetadata() commands to an internal interface

  called CC2420PacketBody, provided by CC2420PacketC

 

* Separated core functionality into different sub-packages/directories

  > Updated micaz, telosb, intelmote2 .platform files

  > Logically organizes code

 

* Updated some LPL architecture

  > Removed continuous modulation because it didn't work 100% and I don't
have 

    time to make it work.  

  > Decreased backoffs and decreased on-time for detects, saving energy.

 

* Updated to the new AMPacket interface; made the radio set the outbound

  packet's destpan after send().

 

 

 

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