SX1231-31SKB915 Semtech, SX1231-31SKB915 Datasheet - Page 51

• Manufacturer Part Number: SX1231-31SKB915
• Description: TVS
• Manufacturer: Semtech

Specifications of SX1231-31SKB915

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

5.5.2.3. 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. This mode is a replacement for the legacy buffered mode in
SX1211/SX1212 transceivers.
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 filling of the FIFO in this case can be controlled by the bit FifoFillCondition. 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 in is made up of the following fields:
5.5.3. Tx Processing (without AES)
In Tx mode the packet handler dynamically builds the packet by performing the following operations on the payload
available in the FIFO:
Only the payload (including optional address and length fields) is required to be provided by the user in the FIFO.
Rev 3 - April 2010
ADVANCED COMMUNICATIONS & SENSING
Preamble (1010...).
Sync word (Network ID).
Optional Address byte (Node ID).
Message data
Optional 2-bytes CRC checksum (Tx only)
Add a programmable number of preamble bytes
Add a programmable Sync word
Optionally calculating CRC over complete payload field (optional length byte + optional address byte + message) and
appending the 2 bytes checksum.
Optional DC-free encoding of the data (Manchester or whitening)
0 to 65535
Preamble
bytes
Optional User provided fields which are part of the payload
Fields added by the packet handler in Tx and processed and removed in Rx
Message part of the payload
0 to 8 bytes
Sync Word
Figure 33. Unlimited Length Packet Format
Address
byte
DC free Data encoding
Payload
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unlimited length
Message
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