CC2430 Datasheet, PDF (174/212 Pages) Texas Instruments – A True System-on-Chip solution for 2.4 GHz IEEE 802.15.4 / ZigBee-TM

CC2430
Radio : System Considerations and Guidelines
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
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 154. This means that the
transmitter used during measurements
must be able to do spreading of the bit
data to chip data. Remember that the chip
sequence transmitted by the test setup is
not the same as the bit sequence, which is
output by CC2430.
• When operating at or below the sensitivity
limit, CC2430 may lose symbol
synchronization in infinite receive mode. A
new SFD and restart of the receiver may
be required to re-gain synchronization.
In an IEEE 802.15.4 system, all
communication is based on packets. The
sensitivity limit specified by [1] is based on
Packet Error Rate (PER) measurements
instead of BER. This is a more realistic
measurement of the true RF performance
since it mirrors the way the actual system
operates.
consumption may be achieved since the
voltage regulators are turned off.
It is recommended to perform PER
measurements instead of BER measurements
to evaluate the performance of IEEE 802.15.4
systems. To do PER measurements, the
following may be used as a guideline:
• A valid preamble, SFD and length field
must be used for each packet.
• The PSDU (see Figure 39 on page 161)
length should be 20 bytes for sensitivity
measurements as specified by [1].
• The sensitivity limit specified by [1] is the
RF level resulting in a 1% PER. The
packet sample space for a given
measurement must then be >> 100 to
have a sufficiently large sample space.
E.g. at least 1000 packets should be used
to measure the sensitivity.
• The data transmitted over air must be
spread according to [1] and the description
on page 154. Pre-generated packets may
be used, although [1] requires that the
PER is averaged over random PSDU data.
• The CC2430 receive FIFO may be used to
buffer data received during PER
measurements, since it is able to buffer up
to 128 bytes.
• The MDMCTRL1H.CORR_THR control
register should be set to 20, as described
in the Demodulator, Symbol Synchronizer
and Data Decision section.
The simplest way of making a PER
measurement will be to use another CC2430 as
the reference transmitter. However, this makes
it difficult to measure the exact receiver
performance.
Using a signal generator, this may either be
set up as O-QPSK with half-sine shaping or as
MSK. If using O-QPSK, the phases must be
selected according to [1]. If using MSK, the
CC2430 Data Sheet (rev. 2.1) SWRS036F
Page 174 of 211