Specifications
Page 53
WT1231H
ADVANCED COMMUNICATIONS & SENSING DATASHEET
5.5.2.3. Unlimi
ted Length Packet Format
Unlimited length packet format is selected when bit PacketFormat is set to 0 and PayloadLength is set to 0.
The user ca
n 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 da
ta 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
Pr
eamb
l
e
0 to
65535
byt
es
Sync
W
ord
0 to 8
by
te
s
A
ddress
byt
e
Message
unlimited
leng
t
h
P
ay
l
oad
Field
s added by the packet handler in Tx and processed and removed in Rx
Message part of the payload
Opti
onal User provided fields which are part of the payload
Figure 35. Unlimited Length Packet
Forma
t
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.