Hi!
On Thu, 2 Jul 2009, Joe Green wrote:
> Hi,
>
> I've read the datasheet for the CC2420 chip and it appears that on the
> receiver side there is one bit signifying the CRC pass/fail. I am trying
> to find where this bit is checked to disable the CRC checking. So far, I
> found two instances that seem to check the CRC.
>
> In lines 171-173 of CC2420ActiveMessageP.nc, the code is:
> if(!(call CC2420PacketBody.getMetadata(msg))->crc) {
> return msg;
> }
>
> Line 296 of CC2420ReceiveP.nc also seems to check the CRC:
> if ( ( buf[ rxFrameLength ] >> 7 ) && rx_buf ) {
>
> Can anyone explain what these two sets of coding do, and let me know if
> there are any other places the crc bit is checked?
These are the only two places that I know. If you take them all the
packets will reach the upper layers.
The check from CC2420ActiveMessageP was added because there were cases in
which packets with bad CRCs were passed to the upper layers.
--
Razvan ME
_______________________________________________
Tinyos-help mailing list
[email protected]
https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
