CC2430 Datasheet, PDF (185/234 Pages) Texas Instruments – A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee-TM

CC2430
Figure 54: Single carrier output
14.30.2 Modulated spectrum
The CC2430 has a built-in test pattern
generator that can generate a pseudo
random sequence using the CRC
generator. This is enabled by setting
MDMCTRL1L.TX_MODE to 3 and issuing a
STXON command strobe. The modulated
spectrum is then available on the RF pins.
The low byte of the CRC word is
transmitted and the CRC is updated with
0xFF for each new byte. The length of the
transmitted data sequence is 65535 bits.
The transmitted data-sequence is then:
[synchronization header] [0x00, 0x78,
0xb8, 0x4b, 0x99, 0xc3, 0xe9, …]
Since a synchronization header (preamble
and SFD) is transmitted in all TX modes,
this test mode may also be used to
transmit a known pseudorandom bit
sequence for bit error testing. Please note
that CC2430 requires symbol
synchronization, not only bit
synchronization, for correct reception.
Packet error rate is therefore a better
measurement for the true RF
performance.
Another option to generate a modulated
spectrum is to fill the TXFIFO with pseudo-
random
data
and
set
MDMCTRL1L.TX_MODE to 2. CC2430 will
then transmit data from the FIFO
disregarding a TXFIFO underflow. The
length of the transmitted data sequence is
then 1024 bits (128 bytes).
A plot of the modulated spectrum from
CC2430 is shown in Figure 55. Note that to
find the output power from the modulated
spectrum, the RBW must be set to 3 MHz
or higher.
CC2430 PRELIMINARY Data Sheet (rev. 1.03) SWRS036A
Page 185 of 232