sure, the flag CC2420_STATUS_TX_ACTIVE returned by the radiochip, when
STXON_CCA is called, is set if the radio started the transmission. Using
just the command strobe STXON the transmission starts, no matter which value
the cca is.
On 6/30/07, Mehedi Bakht <[EMAIL PROTECTED]> wrote:
Hi,
I don't know about the receive part. But if you want to know when the
transmission begins in a tmote (or any other mote that uses CC2420 in TinyOS
2.x) you might have a look at the file CC2420TransmitP.nc. In the
function attemptSend(), there is a line like the following:
status = m_cca ? call STXONCCA.strobe() : call STXON.strobe();
Then there is a line again:
if ( status & CC2420_STATUS_TX_ACTIVE )
congestion = FALSE;
My understanding (I might be wrong) is that if the second condition is
true ( i.e., congestion = FALSE), then the first line (the call to strobe)
actually started the transmission.
--Mehedi
On 6/30/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
>
> Hi Mehedi, thanks for the answer. I've made a LocalTimeMicro component
> with those components you said, but now how can I make sure I get the time
> of arrival of the packet? If I place the "call LocalTimeMicro.get ()"
> in the Receive.receive/Send.sendDone() event, some (or many)
> microseconds have passed since the actual arrival/departure of the packet
> (the SFD detection). What I would like is that the packet's time metadata
> was in microseconds
>
>
>
> On Fri Jun 29 23:58 , 'Mehedi Bakht' <[EMAIL PROTECTED]> wrote:
>
> You might use a microsecond counter (MSP430CounterMicroC if you are
> working on MSP430 platform) and then wire it CounterToLocalTimeC to get the
> current time. You will have to use TransformCounterC component to convert
> the 16-bit values to 32-bit values.
>
> Hope it helps.
>
> --Mehedi
>
> On 6/29/07, [EMAIL PROTECTED] <[EMAIL PROTECTED] > wrote:
> >
> >
> > Hello tinyos-ers!
> >
> > I'm using the "time" metadata field to know when the packet was
> > received/sent, but that is in 32khz time units. Is there any way to know the
> > time in microseconds? And possibly in a larger integer than 16bit?
> >
> >
> > Hope to hear from you,
> >
> > thanks in advance
> >
> >
> >
> >
> >
>
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