right, I just remembered that point in the cc2420 datasheet. I have a last question: the transmission of a packet is performed if the RSSI value is greater than a certain threshold, the CCA. The 3 CCA modes are
0 reserved 1 clear channel when received energy is below threshold 2 clear channel when not receiving valid IEEE data 3 clear channel when not receiving valid IEEE data and below threshold I guess the CCA value is a 8 bit unsigned integer 2 complement, so if I need to transmit a packet, regardless of other transmitting nod I should set the CCA value to its minimum, lilke -128dBm, or 0xFF. I know during the reception of a packet the RSSI is averaged over 8 symbols after the SFD has been detected. During the transmission how does is it calculated? Can I read it just using the command call function c.. HPLCC2420.read(RSSI_REG)? On 6/19/07, David Moss <[EMAIL PROTECTED]> wrote:
The default mode for the radio is Rx mode – after it transmits a packet, it automatically switches back to Rx on the hardware. If you attempt to transmit using STXON without clear channel assessments, then your radio will not only **not** receive the other transmitter's packet, but it will cause channel interference that will prevent all other motes in the area from receiving that packet. That's the point of backoffs and CCA (clear channel assessment) – determine if the channel is clear before attempting a transmission. -David ------------------------------ *From:* [EMAIL PROTECTED] [mailto: [EMAIL PROTECTED] *On Behalf Of *roberto pagliari *Sent:* Tuesday, June 19, 2007 3:24 PM *To:* [email protected] *Subject:* [Tinyos-help] about CC2420 hi all, within RadioControlM I can see CC2420Control.RxMode(), but, after a packet has been sent I cant find any call to CC2420.RxMode() or SXON oscillator. where is it done? the second question is: once the transmitter oscillator STXON has been enabled, if an incoming message arrives, will it be lost? thank you
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