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ARF53 User GuideRef. 08-07-V6-lmn p 14Specific string when specifiedTransceiver modeThe transceiver mode used a secured addressed protocol.The communication is always half-duplex. The radio transmission is processedprior to the radio reception. When the transceiver is sending a radio packet, itis not able to decode any incoming radio packet.If no data are sent on the serial link, the modem is waiting for radioreception. Each radio packet sent by another modem is received and thevalidated data extracted from the radio packet are sent on the serial link.All the data received on the serial link are encapsulated in a radio packet.In transmission mode, data received on the serial link are sent on the radiolink with the following format: header> DATA .Preamble, synchronisation and postambule are used for the radio reception.The packet header contains the following fields : packet length, number ofretries and packet number, target address.The CRC follows the data and check the integrity of the radio packet.The Target Address field is set up with S256 register. The Target Addressvalue 0000 is a broadcast address.In reception mode: The Address> field of the radio packet ischecked (if different of 0000) with the reception address (S252).If the radio packet address matches the transceiver reception address (S252),DATA (and only DATA) are transmitted on the serial linkOtherwise received data are silently discarded.Transceiver state machineWhen operating in transceiver mode the 'RF transmission' state machine is:Idle state of the transceiver: by default the transceiver is waiting forincoming data on the RS232 link and for incoming radio packet on the radiolink.Processing incoming RS232 data: the incoming RS232 data are internallybuffered. The buffered data are encapsulated in a radio packet andtransmitted.
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