CC2550_13 Datasheet, PDF (45/61 Pages) Texas Instruments – Low-Cost Low-Power 2.4 GHz RF Transmitter

CC2550
0x13: MDMCFG1 – Modulator Configuration
Bit Field Name
Reset
R/W Description
7 FEC_EN
0
6:4 NUM_PREAMBLE[2:0] 2 (010)
3:2 Reserved
1:0 CHANSPC_E[1:0]
2 (10)
R/W Enable Forward Error Correction (FEC) with interleaving for
packet payload
0 = Disable
1 = Enable
R/W Sets the minimum number of preamble bytes to be
transmitted
Setting
Number of preamble bytes
0 (000)
2
1 (001)
3
2 (010)
4
3 (011)
6
4 (100)
8
5 (101)
12
6 (110)
16
7 (111)
24
R0
R/W 2 bit exponent of channel spacing
Bit Field Name
7:0 CHANSPC_M[7:0]
0x14: MDMCFG0 – Modulator Configuration
Reset
R/W Description
248 (0xF8)
R/W
8-bit mantissa of channel spacing (initial 1 assumed). The
channel spacing is multiplied by the channel number CHAN and
added to the base frequency. It is unsigned and has the format:
( ) ∆f_CHANNEL
=
f _{XOSC â‹}
2 ¹⁸
256 + CHANSPC _ M
⋅ 2^{CHANSPC _ E} ⋅ CHAN
The default values give 199.951 kHz channel spacing (the
closest setting to 200 kHz), assuming 26.0 MHz crystal
frequency.
SWRS039B
Page 45 of 58