Yes, the decision whether to do CCA before sending out a packet is
factored out to CC2420XDriverConfig. We, in fact, need this
functionality to support software ACKs:
CC2420XDriverConfig.requiresRssiCca() will return TRUE for data
packets and FALSE for ACK packets.

Janos

On Wed, Oct 5, 2011 at 7:15 PM, Eric Decker <[email protected]> wrote:
>
>
> On Wed, Oct 5, 2011 at 8:59 AM, Janos Sallai <[email protected]>
> wrote:
>>
>> Sean,
>>
>> Modify tos/chips/cc2420x/CC2420XRadioP.nc such that
>> CC2420XDriverConfig.requiresRssiCca() always returns FALSE. This will
>> prevent the radio driver from carrying out CCA before sending the
>> packet. That is, the packet will be transmitted even if the channel is
>> busy.
>
> Don't you need to tweak something underneath like in the cc2420 h/w itself
> too?
> Or is the above sufficient to cause the software driver to configure the h/w
> appropriately?
>
>>
>> Janos
>>
>> Janos
>> On Wed, Oct 5, 2011 at 1:22 AM, Xiaowei <[email protected]> wrote:
>> > Hi fellows,
>> > Any idea on how to disable csma on cc2420x (tinyOS 2.x)?
>> > On cc2420 we can achieve this by setting "ccaOn = TRUE" to "ccaOn =
>> > FALSE"
>> > in tos/chips/cc2420/csma/CC2420CsmaP.nc, does this disable csma
>> > completely
>> > or it just disables CA part in CSMA-CA?
>> > Thank you,
>> > Sean
>> >
>> > _______________________________________________
>> > Tinyos-help mailing list
>> > [email protected]
>> > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
>> >
>> _______________________________________________
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>
>
>
> --
> Eric B. Decker
> Senior (over 50 :-) Researcher
>
>
>
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