CC2400 Chipcon AS, CC2400 Datasheet - Page 45

• Manufacturer Part Number: CC2400
• Description: 2.4 GHz RF Transceiver
• Manufacturer: Chipcon AS

Frequency Programming
The
programming the frequency word in the
FSDIV configuration register.
The frequency word is 12 bits and is
located
Writing/reading FSDIV[11:0] will give
the frequency directly in MHz. (The bits
FSDIV.FREQ[11:10] are hardwired to
‘10’ giving a fixed offset of 2048.)
Transmit mode
In
upconversion scheme is used (i.e. no
intermediate frequency for the modulated
baseband
MDMTST0.TX_1MHZ_OFFSET_N=1
therefore
initialization sequence (ref. Figure 15).
When MDMTST0.TX_1MHZ_OFFSET_N=1
the transmit channel center frequency
(carrier frequency), f
directly by:
The two FSK modulation frequencies are
given by:
Chipcon AS
f
c
=
FREQ
transmit
operating
[
11
be
in
SmartRF
:
0
mode
]
set
=
frequency
2048
FSDIV.FREQ[11:0].
®
c
CC2400 PRELIMINARY Datasheet (rev. 1.1), 2003-10-02
,
during
+
an
in MHz is given
FREQ
is
I/Q
[
9
the
:
set
0
signal).
]
direct
must
chip
by
SmartRF
where f
f
MDMCTRL.MOD_DEV[6:0] and given by
(in kHz):
The default value is MOD_DEV = 64 giving
250 kHz deviation.
The TX_GAUSSIAN_FILTER bit in the
GRMDM register controls the Gaussian
shaping of the modulation signal. See also
page 37.
Receive mode
Low side LO injection is used, hence:
where, f
channel and f
Thus, in receive mode the frequency
generated by the frequency synthesizer,
f
frequency.
dev
c
f
,
dev
must be programmed to be the LO
=
±
dev
. 3
RF
9062
is
is the FSK frequency deviation.
is the center frequency of the
IF
⋅
f
= 1 MHz.
MOD
f
f
LO
0
1
= f
= f
= f
®
programmed
c
c
RF
_
− f
+ f
DEV
− f
CC2400
dev
dev
IF
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6
0 :
Page 45 of 73
]
with