[Tinyos-help] CRC in CC2420

[Razvan Musaloiu-E.]

Hi!

On Wed, 11 Feb 2009, Jordi Pérez wrote:

> Dear all,
>
> For CC2420, if AUTOCRC is set, will the hardware reject CRC-error packet
> automatically?
> If true, then is it possible to receive those packets but with AUTOCRC still
> being set? I want to receive this packets and rebuild them.
>

The CC2420 is not discarding the packets with bad CRC. What does is to 
indicate using a bit that the packet was bad (page 38, section 16.4 
from [1]). The TinyOS driver for CC2420 inspects this bit and discards the 
packets if that bit is not 1. You can see this happening in 
the RXFIFO.readDone event from CC2420ReceiveP.nc. The switch branch of 
interest is 'case S_RX_PAYLOAD:'.

The other filtering that you'll have to disable is in the 
SubReceive.receive event from CC2420ActiveMessageP.nc.

[1] http://focus.ti.com/lit/ds/symlink/cc2420.pdf

--
Razvan ME