Texas Instruments CC112 Series, User Manual, Page: 71 / 109

CC112X/CC1175
SWRU295C Page 71 of 108
PREAMBLE_CFG1 - Preamble Length Configuration
Bit no. Name Reset R/W Description
7:6 PREAMBLE_CFG1_NOT_USED 0x00 R
5:2 NUM_PREAMBLE 0x05 R/W Sets the minimum number of preamble bits to be transmitted
0000 No preamble
0001 0.5 byte
0010 1 byte
0011 1.5 bytes
0100 2 bytes
0101 3 bytes
0110 4 bytes
0111 5 bytes
1000 6 bytes
1001 7 bytes
1010 8 bytes
1011 12 bytes
1100 24 bytes
1101 30 bytes
1110 Reserved
1111 Reserved
1:0 PREAMBLE_WORD 0x00 R/W Preamble Byte Configuration.
PREAMBLE_WORD
determines how a preamble
byte looks like. Note that when 4'ary modulation is used the preamble uses 2'are
modulation (the baud rate is kept the same)
00 10101010 (0xAA)
01 01010101 (0x55)
10 00110011 (0x33)
11 11001100 (0xCC)
PREAMBLE_CFG0 - Preamble Length Configuration
Bit no. Name Reset R/W Description
7:6 PREAMBLE_CFG0_NOT_USED 0x00 R
5 PQT_EN 0x01 R/W Preamble Detection Enable
0 Preamble detection disabled
1 Preamble detection enabled
4 PQT_VALID_TIMEOUT 0x00 R/W PQT Start-up Timer.
PQT_VALID_TIMEOUT
sets the number of symbols that
must be received before
PQT_VALID
is asserted
0 16 symbols
1 43 symbols
3:0 PQT 0x0A R/W Soft Decision PQT. A preamble is detected when the calculated preamble
qualifier value (
PQT_SYNC_ERR.PQT_ERROR
) is less than
PQT
). A low threshold
value means a strict preamble qualifier (preamble must be of high quality to be
accepted) while a high threshold value will accept preamble of a poorer quality
(increased probability of detecting „false‟ preamble)
FREQ_IF_CFG - RX Mixer Frequency Configuration
Bit no. Name Reset R/W Description
7:0 FREQ_IF 0x40 R/W Digital Receiver Mixer Frequency
15
2
_ IF FREQ f
f
XOSC
IF
Note that FREQ_IF is two's complement, hence both positive and negative IF is
supported