CC2430-RTR1-F64 datasheet(189/234 Pages) TI

189 / 234 page

CC2430

CC2430 PRELIMINARY Data Sheet (rev. 1.03) SWRS036A

Page 189 of 232

The external components should be as

small as possible (0402 is recommended)

and surface mount devices must be used.

If using any external high-speed digital

devices, caution should be used when

placing these in order to avoid interference

with the RF circuitry.

A Development Kit, CC2430DK, with a

fully assembled Evaluation Module is

available. It is strongly advised that this

reference layout is followed very closely in

order to obtain the best performance.

The schematic, BOM and layout Gerber

files for the reference designs are all

available from the Chipcon website.

14.33 Antenna Considerations

CC2430 can be used together with various

types of antennas. A differential antenna

like a dipole would be the easiest to

interface not needing a balun (balanced to

un-balanced transformation network).

The length of the

λ/2-dipole antenna is

given by:

L = 14250 / f

where f is in MHz, giving the length in cm.

An antenna for 2450 MHz should be 5.8

cm. Each arm is therefore 2.9 cm.

Other commonly used antennas for short-

range

communication

are

monopole,

helical and loop antennas. The single-

ended monopole and helical would require

a balun network between the differential

output and the antenna.

Monopole

antennas

are

resonant

antennas with a length corresponding to

one quarter of the electrical wavelength

(

λ/4). They are very easy to design and

can be implemented simply as a “piece of

wire” or even integrated into the PCB.

The length of the

λ/4-monopole antenna is

given by:

L = 7125 / f

where f is in MHz, giving the length in cm.

An antenna for 2450 MHz should be 2.9

cm.

Non-resonant monopole antennas shorter

than

λ/4 can also be used, but at the

expense of range. In size and cost critical

applications such an antenna may very

well be integrated into the PCB.

Enclosing the antenna in high dielectric

constant material reduces the overall size

of the antenna. Many vendors offer such

antennas intended for PCB mounting.

Helical antennas can be thought of as a

combination of a monopole and a loop

antenna. They are a good compromise in

size critical applications. Helical antennas

tend to be more difficult to optimize than

the simple monopole.

Loop antennas are easy to integrate into

the PCB, but are less effective due to

difficult impedance matching because of

their very low radiation resistance.

For low power applications the differential

antenna is recommended giving the best

range and because of its simplicity.

The antenna should be connected as

close as possible to the IC. If the antenna

is located away from the RF pins the

antenna should be matched to the feeding

transmission line (50

Ω).

14.34 CSMA/CA Strobe Processor

The

Command

Strobe/CSMA-CA

Processor (CSP) provides the control

interface between the CPU and the Radio

module in the

CC2430.

The CSP interfaces with the CPU through

the SFR register RFST and the RF

registers CSPX, CSPY, CSPZ, CSPT and

CSPCTRL. The CSP produces interrupt

requests to the CPU. In addition the CSP

interfaces with

the MAC

Timer

observing MAC Timer overflow events.

The CSP allows the CPU to issue

command strobes to the radio thus

controlling the operation of the radio.

The CSP has two modes of operation as

follows, which are described below.

•

Immediate

Command

Strobe

execution.

•

Program execution

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