[Tinyos-help] Coding for CRC checking (CC2420)

[Joe Green]

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?

Thanks,
Joe



      
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