SX1276 View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SX1276' PDF : 132 Pages View PDF
SX1276/77/78/79
WIRELESS, SENSING & TIMING
DATASHEET
Optional 2-bytes CRC checksum
Optional DC free data coding
CRC checksum calculation
Preamble
Sync Word
0 to 65536 bytes 0 to 8 bytes
Length
byte
Address
byte
Message
Up to 255 bytes
CRC
2-bytes
Payload
(min 2 bytes)
Fields added by the packet handler in Tx and processed and removed in Rx
Optional User provided fields which are part of the payload
Message part of the payload
Figure 34. Variable Length Packet Format
Unlimited Length Packet Format
Unlimited length packet format is selected when bit PacketFormat is set to 0 and PayloadLength is set to 0. The user can
then transmit and receive packet of arbitrary length and PayloadLength register is not used in Tx/Rx modes for counting
the length of the bytes transmitted/received.
In Tx the data is transmitted depending on the TxStartCondition bit. On the Rx side the data processing features like
Address filtering, Manchester encoding and data whitening are not available if the sync pattern length is set to zero
(SyncOn = 0). The CRC detection in Rx is also not supported in this mode of the packet handler, however CRC generation
in Tx is operational. The interrupts like CrcOk & PayloadReady are not available either.
An unlimited length packet shown below is made up of the following fields:
Preamble (1010...).
Sync word (Network ID).
Optional Address byte (Node ID).
Message data
Optional 2-bytes CRC checksum (Tx only)
DC free Data encoding
Preamble
0 to 65535
bytes
Sync Word
0 to 8 bytes
Address
byte
Message
unlimited length
Payload
Fields added by the packet handler in Tx and processed and removed in Rx
Message part of the payload
Optional User provided fields which are part of the payload
4.2.13.3. Tx Processing
Figure 35. Unlimited Length Packet Format
Rev. 4 - March 2015
©2015 Semtech Corporation
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