RFM69HCW Datasheet, PDF (53/79 Pages) List of Unclassifed Manufacturers – ISM TRANSCEIVER MODULE

ADVANCED COMMUNICATIONS & SENSING
RFM69HCW
DATASHEET
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
RF63/RF64 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:
‹ _{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
Figure 34. Unlimited Length Packet Format
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:
‹ 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)
andappending the 2 bytes checksum.
‹ Optional DC-free encoding of the data (Manchester or whitening)
Only the payload (including optional address and length fields) is required to be provided by the user in the FIFO.
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