CC1110Fx / CC1111Fx
13.8 Packet Handling Hardware Support
The CC1110Fx/CC1111Fx has built-in hardware
support for packet oriented radio protocols.
Whitening of the data with a PN9
sequence.
In transmit mode, the packet handler can be
configured to add the following elements to the
packet:
Forward error correction by the use of
interleaving and coding of the data
(convolutional coding).
A programmable number of preamble
bytes
In receive mode, the packet handling support
will de-construct the data packet by
implementing the following (if enabled):
A two byte synchronization (sync) word.
Can be duplicated to give a 4-byte sync
word (recommended). It is not possible
to only insert preamble or only insert a
sync word.
Preamble detection
Sync word detection
CRC computation and CRC check
One byte address check
A CRC checksum computed over the
data field
Packet length check (length byte
The recommended setting is 4-byte preamble
and 4-byte sync word, except for 500 kBaud
data rate where the recommended preamble
length is 8 bytes.
checked against
maximum length)
a
programmable
De-whitening
De-interleaving and decoding
In addition, the following can be implemented
on the data field and the optional 2-byte CRC
checksum:
Optionally, two status bytes (see Table 64 and
Table 65) with RSSI value, Link Quality
Indication, and CRC status can be appended
to the received packet.
Bit
Field Name
Description
RSSI value
7:0
RSSI
Table 64: Received Packet Status Byte 1
(first byte appended after the data)
Bit
Field name
Description
7
CRC_OK
1: CRC for received data OK (or
CRC disabled)
0: CRC error in received data
6:0
LQI
The
Link
Quality
Indicator
estimates how easily a received
signal can be demodulated
Table 65: Received Packet Status Byte 2
(second byte appended after the data)
Note that register fields that control the packet
handling features should only be altered when
CC1110Fx/CC1111Fx is in the IDLE state.
regulation loops in the receiver uniform
operation conditions (no data dependencies).
Real world data often contain long sequences
of zeros and ones. Performance can then be
improved by whitening the data before
transmitting, and de-whitening the data in the
receiver. With CC1110Fx/CC1111Fx, this can be
13.8.1
Data Whitening
From a radio perspective, the ideal over the air
data are random and DC free. This results in
the smoothest power distribution over the
occupied bandwidth. This also gives the
done
automatically
by
setting
PKTCTRL0.WHITE_DATA=1. All data, except
the preamble and the sync word, are then
XOR-ed with a 9-bit pseudo-random (PN9)
SWRS033H
Page 193 of 246
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