c
f
2405
5(k 11)
MHz
k
11, 26
=
+
-
Î
é
ù
é
ù
ë
û
ë
û
Frequency and Channel Programming
Table 23-1. Frame Filtering and Source Matching Memory Map (continued)
ADDRESS
REGISTER/VARIABLE
ENDIAN
DESCRIPTION
Extended address matching. When there is a match on entry ext_n,
0x6160
SRCRESMASK0
bits 2n and 2n + 1 are set in
SRCRESMASK
.
SOURCE ADDRESS TABLE
0x615E
–
0x615F
short_23
LE
0x615C
–
0x615D
panid_23
LE
Two individual short-address entries (combination of 16-bit PAN ID
ext_11
LE
and 16-bit short address) or one extended address entry
0x615A
–
0x615B
short_22
LE
0x6158
–
0x6159
panid_22
LE
...
...
...
...
...
...
0x610E
–
0x610F
short_03
LE
0x610C
–
0x610D
panid_03
LE
Two individual short address entries (combination of 16-bit PAN ID
ext_01
LE
and 16-bit short address) or one extended address entry
0x610A
–
0x610B
short_02
LE
0x6108
–
0x6109
panid_02
LE
0x6106
–
0x6107
short_01
LE
0x6104
–
0x6105
panid_01
LE
Two individual short address entries (combination of 16-bit PAN ID
ext_00
LE
and 16-bit short address) or one extended address entry
0x6102
–
0x6103
short_00
LE
0x6100
–
0x6101
panid_00
LE
23.5 Frequency and Channel Programming
The carrier frequency is set by programming the 7-bit frequency word located in
FREQCTRL.FREQ[6:0]
.
Changes take effect after the next recalibration. Carrier frequencies in the range from 2394 MHz to 2507
MHz are supported. The carrier frequency f
C
, in MHz, is given by f
C
= (2394 +
FREQCTRL.FREQ[6:0]
)
MHz, and is programmable in 1-MHz steps.
IEEE 802.15.4-2006 specifies 16 channels within the 2.4-GHz band. They are numbered 11 through 26
and are 5 MHz apart. The RF frequency of channel k is given by
(4)
For operation in channel k, the
FREQCTRL.FREQ
register should therefore be set to
FREQCTRL.FREQ
= 11 + 5 (k
–
11).
23.6 IEEE 802.15.4-2006 Modulation Format
This section is meant as an introduction to the 2.4-GHz direct-sequence spread-spectrum (DSSS) RF
modulation format defined in IEEE 802.15.4-2006. For a complete description, see the standard document
[1].
The modulation and spreading functions are illustrated at the block level in
. Each byte is
divided into two symbols, 4 bits each. The least-significant symbol is transmitted first. For multibyte fields,
the least-significant byte is transmitted first, except for security-related fields, where the most-significant
byte is transmitted first.
Each symbol is mapped to one out of 16 pseudorandom sequences, 32 chips each. The symbol-to-chip
mapping is shown in
. The chip sequence is then transmitted at 2 Mchips/s, with the
least-significant chip (C
0
) transmitted first for each symbol. The transmitted bit stream and the chip
sequences are observable on GPIO pins P1[0:5]. See
for details on how to configure the GPIO
to do this.
226
CC253x Radio
SWRU191C
–
April 2009
–
Revised January 2012
Copyright
©
2009
–
2012, Texas Instruments Incorporated