Silicon Laboratories EZRADIOPRO Si4060, Programming Manual

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10.12. Custom Packet Reception with Matching Capability
The purpose of the packet match reception example code is to demonstrate how the radio can filter packets that
are intended for one receiver. The Radio ICs of Si4x6x family provide for fully configurable matching functionality
on up to 4 data bytes in the data fields (field1 to field5) of the packet. The match function is typically used to
implement header check or broadcast check capability that is used to quickly determine if a packet is intended for
one receiver node in a network. If a match is not found, the chip can abort reception of the packet and proceed to
scanning for the next packet.
There are four match bytes at configurable locations in the packet. They must be located within the first 32 bytes
following the end of the Sync Word. It is also necessary that the offset of the match bytes be in ascending order.
The offset location of match #1 byte must be less than the location of match #2 byte, and so on. No two match
bytes may have the same offset location. It is not possible to configure two different match functions against the
same received data byte.
Figure 49. Packet Match Working Mechanism
Once the location of each match byte has been specified, it is next necessary to configure their mask values. A
mask value represents a bit pattern which is logically and’ed (bit-wise) with the corresponding received match byte.
These mask values are specified in the mask registers’ range from 1 to 4. The result is then compared with the
corresponding match value. For each successive match byte, it is possible to
logically-or or logically-and its result
with the cumulative logical result from the previous matches.