CC2430 Datasheet, PDF (187/234 Pages) Texas Instruments – A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee-TM

CC2430
buffer data at its own speed, reducing the
workload and timing requirements. DMA
transfers may be used to efficiently move
data to and from the radio FIFOs.
The relatively high data rate of CC2430
also reduces the average power
consumption compared to the 868 / 915
MHz bands defined by [1], where only 20 /
40 kbps are available. CC2430 may be
powered up a smaller portion of the time,
so that the average power consumption is
reduced for a given amount of data to be
transferred.
14.31.4 Crystal accuracy and drift
A crystal accuracy of ±40 ppm is required
for compliance with IEEE 802.15.4 [1].
This accuracy must also take ageing and
temperature drift into consideration.
A crystal with low temperature drift and
low aging could be used without further
compensation. A trimmer capacitor in the
crystal oscillator circuit (in parallel with
C191 in Figure 6) could be used to set the
initial frequency accurately.
For non-IEEE 802.15.4 systems, the
robust demodulator in CC2430 allows up to
120 ppm total frequency offset between
the transmitter and receiver. This could
e.g. relax the accuracy requirement to 60
ppm for each of the devices.
Optionally in a star network topology, the
FFD could be equipped with a more
accurate crystal thereby relaxing the
requirement on the RFD. This can make
sense in systems where the RFDs ship in
higher volumes than the FFDs.
14.31.5 Communication robustness
CC2430 provides very good adjacent,
alternate and co channel rejection, image
frequency suppression and blocking
properties. The CC2430 performance is
significantly better than the requirements
imposed by [1]. These are highly important
parameters for reliable operation in the 2.4
GHz band, since an increasing number of
devices/systems are using this license free
frequency band.
14.31.6 Communication security
The hardware encryption and
authentication operations in CC2430 enable
secure communication, which is required
for many applications. Security operations
require a lot of data processing, which is
costly in an 8-bit microcontroller system.
The hardware support within CC2430
enables a high level of security with
minimum CPU processing requirements.
14.31.7 Low cost systems
As the CC2430 provides 250 kbps multi-
channel performance without any external
filters, a very low cost system can be
made (e.g. two layer PCB with single-
sided component mounting).
A differential antenna will eliminate the
need for a balun, and the DC biasing can
be achieved in the antenna topology.
14.31.8 Battery operated systems
In low power applications, the CC2430
should be placed in the low-power modes
PM2 or PM3 when not being active. Ultra
low power consumption may be achieved
since the voltage regulators are turned off.
14.31.9 BER / PER measurements
CC2430 includes test modes where data is
received infinitely and output to pins. The
required test modes are selected with the
RF
register
bits
MDMCTRL1L.TX_MODE[1:0]
and
MDMCTRL1L.RX_MODE[1:0].
These
modes may be used for Bit Error Rate
(BER) measurements. However, the
following precautions must be taken to
perform such a measurement:
• A preamble and SFD sequence
must be used, even if pseudo
random data is transmitted, since
receiving the DSSS modulated
signal
requires
symbol
synchronization,
not
bit
synchronization like e.g. in 2FSK
systems.
The
SYNCWORDH:SYNCWORDL may be
set to another value to fit to the
measurement setup if necessary.
• The data transmitted over air must
be spread according to [1] and the
description on page 165. This
means that the transmitter used
during measurements must be
able to do spreading of the bit
CC2430 PRELIMINARY Data Sheet (rev. 1.03) SWRS036A
Page 187 of 232