Texas Instruments SimpleLink CC2620 Technical Reference Manual page 1595

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Two kinds of addresses are supported. With the first option, the address is part of the header. In this case,
the address size can be from 1 to 31 bits. The other option is to have an address after the header. If so,
this address consists of between 1 and 8 bytes. To use an address as part of the header,
addrConf.addrType must be set to 1. The number of bits in the address is given by addrConf.addrSize.
These bits are read from bit number addrConf.addrPos from the first bit of the header. To use an address
after the header, addrConf.addrType must be set to 0. In this case, the number of bytes in the address is
given by addrConf.addrSize.
The received address is compared to an address list pointed to by pAddr. The address to compare against
this list is as received. In addition, one bit identifying the sync word is concatenated with the address as
the MSBs, if one of the following conditions is fulfilled:
• syncWord1 ≠ 0 and addrConf.addrType = 1
• syncWord1 ≠ 0, addrConf.addrType = 0, and addrConf.addrPos ≠ 0
This extra bit is 0 if the received sync word was syncWord0, and 1 if the received sync word was
syncWord1. The entries in the address list have a size of 8, 16, 32, or 64 bits; the smallest size that can fit
the address size, including the sync word identification bit if applicable. The number of entries in the
address list is given by addrConf.numAddr. The radio CPU scans through the addresses in the address
list and compares it to the received address. If there is no match, the further treatment depends on
pktConf.filterOp. If this is 0, reception is stopped and synch search is restarted. If it is 1, the packet is
received as if the address had matched, but marked as ignored.
If addrConf.addrSize is zero, no address is used. In this case, pAddr is ignored and must be NULL.
If the packet is being received, the data is placed in the receive buffer, as in
buffer is found from the receive queue pointed to by pQueue. If pQueue is NULL, the packet is never
stored.
The header is received as one field in the bit ordering programmed in the radio. If the header has more
than 8 bits and rxConf.bIncludeHdr is 1, the header is always written in little-endian byte order to the
receive buffer. If the radio is configured to receive the MSB first, the last header byte stored in the receive
buffer is received first. The payload is stored byte by byte, so after the header, no swapping of bytes
occurs regardless of bit ordering over the air.
If pktConf.bUseCrc is 1, a CRC is received and checked at the end. The number of CRC bits, polynomial,
and initialization are as configured in the radio. If pktConf.bCrcIncSw is 1, the received sync word
(assuming it to be exactly equal to syncWord0 or syncWord1) is included in the data set over which the
CRC is calculated. If pktConf.bCrcIncHdr is 1, the received header is included in the data set over which
the CRC is calculated. The payload, including the optional address after the header, is always used for
calculating the CRC. If pktConf.bUseCrc is 0, the treatment is as for CRC OK.
If whitening is enabled, the optional header is subject to dewhitening only if pktConf.bCrcIncHdr is 1. The
payload including the optional address after the header, and the received CRC, are always subject to
dewhitening when enabled. The dewhitening is done before the CRC is evaluated.
If a status byte is appended (RXConf.bAppendStatus is 1) to the packet, it is formatted as follows (see
Table 23-107). If addrConf.addrSize is nonzero, the addressInd field is the first index into the address list
that matched the received address if an address match existed. Otherwise, addressInd is 0. The
syncWordId field is 0 if the received sync word was syncWord0, and 1 if syncWord1. The result field is
written according to
23.7.5.5 Carrier-Sense Operation (CC13xx Only)
The carrier-sense operation detects if a signal is present. This has two main purposes; either to turn off
the radio instead of receiving if no signal is present, or to transmit only if no signal is present. The carrier-
sense operation can be used with the command CMD_PROP_CS to chain with another operation (for
instance, a transmit operation). The details of these commands are described in the following subsections.
SWCU117C – February 2015 – Revised September 2015
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Table 23-150.
Copyright © 2015, Texas Instruments Incorporated
Proprietary Radio
Section 23.5.3.1. This receive
Radio
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