CC2500_06 Datasheet, PDF (59/84 Pages) Texas Instruments – Single Chip Low Cost Low Power RF Transceiver

CC2500
Bit Field Name
7:5 Reserved
4:0 FREQ_IF[4:0]
0x0B: FSCTRL1 – Frequency synthesizer control
Reset
R/W Description
15 (0x0F)
R0
R/W The desired IF frequency to employ in RX. Subtracted from FS
base frequency in RX and controls the digital complex mixer in
the demodulator.
f _IF
=
f _XOSC
2¹⁰
⋅ FREQ _ IF
The default value gives an IF frequency of 381 kHz, assuming
a 26.0 MHz crystal.
Bit Field Name
7:0 FREQOFF[7:0]
0x0C: FSCTRL0 – Frequency synthesizer control
Reset
R/W Description
0 (0x00) R/W Frequency offset added to the base frequency before being
used by the FS. (2-complement).
Resolution is F_XTAL/2¹⁴ (1.59 - 1.65 kHz); range is ±202 kHz to
±210 kHz, dependent of XTAL frequency.
Bit Field Name
7:6 FREQ[23:22]
5:0 FREQ[21:16]
0x0D: FREQ2 – Frequency control word, high byte
Reset
R/W Description
1 (01)
30
(0x1E)
R
FREQ[23:22] is always binary 01 (the FREQ2 register is in the range 85 to
95 with 26-27 MHz crystal)
R/W FREQ[23:0] is the base frequency for the frequency synthesiser in
increments of F_XOSC/2¹⁶.
[ ] f_carrier
=
f _XOSC
2¹⁶
⋅ FREQ
23 : 0
The default frequency word gives a base frequency of 2464 MHz,
assuming a 26.0 MHz crystal. With the default channel spacing settings,
the following FREQ2 values and channel numbers can be used:
FREQ2 Base frequency Frequency range (CHAN numbers)
91 (0x5B)
2386 MHz
2400.2-2437 MHz (71-255)
92 (0x5C)
2412 MHz
2412-2463 MHz (0-255)
93 (0x5D)
2438 MHz
2431-2483.4 MHz (0-227)
94 (0x5E)
2464 MHz
2464-2483.4 MHz (0-97)
Bit Field Name
7:0 FREQ[15:8]
0x0E: FREQ1 – Frequency control word, middle byte
Reset
R/W Description
196 (0xC4) R/W Ref. FREQ2 register
Bit Field Name
7:0 FREQ[7:0]
0x0F: FREQ0 – Frequency control word, low byte
Reset
R/W Description
236 (0xEC) R/W Ref. FREQ2 register
PRELIMINARY Data Sheet (Rev.1.2) SWRS040A
Page 59 of 83