[Tinyos-help] always confused by this segment of code

[Tie Luo]

I have been confused for a long time. Can anybody help?

T2: CC2420TransmitP.nc  void attemptSend():

1    status = m_cca ? call STXONCCA.strobe() : call STXON.strobe();

2    if ( !( status & CC2420_STATUS_TX_ACTIVE ) ) {

3          status = call SNOP.strobe();

4         if ( status & CC2420_STATUS_TX_ACTIVE )    congestion = FALSE;
    }

My question is: Why read status twice?

I have read the datasheet, and it does not tell the reason.

Many thanks!

-- 
Regards,
Tie
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