CC2510_15 Datasheet, PDF (190/245 Pages) Texas Instruments – Low-Power SoC (System-on-Chip) with MCU, Memory,2.4 GHz RF Transceiver, and USB Controller

CC2511F8 - Not Recommended for New Designs
13.8 Packet Handling Hardware Support
The CC2510Fx/CC2511Fx has built-in hardware
support for packet oriented radio protocols.
In transmit mode, the packet handler can be
configured to add the following elements to the
packet:
• A programmable number of preamble
bytes
• 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.
• A CRC checksum computed over the
data field
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.
In addition, the following can be implemented
on the data field and the optional 2-byte CRC
checksum:
CC2510Fx / CC2511Fx
• Whitening of the data with a PN9
sequence.
• Forward error correction by the use of
interleaving and coding of the data
(convolutional coding).
In receive mode, the packet handling support
will de-construct the data packet by
implementing the following (if enabled):
• Preamble detection
• Sync word detection
• CRC computation and CRC check
• One byte address check
• Packet length check (length byte
checked against a programmable
maximum length)
• De-whitening
• De-interleaving and decoding
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
7:0 RSSI
RSSI value
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
CC2510Fx/CC2511Fx is in the IDLE state.
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
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 CC2510Fx/CC2511Fx, this can be
done
automatically
by
setting
PKTCTRL0.WHITE_DATA=1. All data, except
the preamble and the sync word, are then
SWRS055G
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