CC2500-RTR1 datasheet(55/96 Pages) TI

55 / 96 page

CC2500

SWRS040C

Page 55 of 89

31.2

Frequency

Hopping

and

Multi-

Channel Systems

The 2.400 – 2.4835 GHz band is shared by

many systems both in industrial, office and

home

environments.

therefore

recommended

use

frequency

hopping

spread spectrum (FHSS) or a multi-channel

protocol

because

the

frequency

diversity

makes the system more robust with respect to

interference from other systems operating in

the same frequency band. FHSS also combats

multipath fading.

CC2500 is highly suited for FHSS or multi-

channel systems due to its agile frequency

synthesizer

and

effective

communication

interface. Using the packet handling support

and data buffering is also beneficial in such

systems as these features will significantly

offload the host controller.

Charge pump current, VCO current and VCO

capacitance array calibration data is required

for

each

frequency

when

implementing

frequency hopping for

CC2500. There are 3

ways of obtaining the calibration data from the

chip:

1) Frequency hopping with calibration for each

hop. The PLL calibration time is approximately

720 µs. The blanking interval between each

frequency hop is then approximately 810 us.

2) Fast frequency hopping without calibration

for each hop can be done by calibrating each

frequency at startup and saving the resulting

FSCAL3

, FSCAL2 and FSCAL1 register values

in MCU memory. Between each frequency

hop, the calibration process can then be

replaced by writing the FSCAL3, FSCAL2 and

FSCAL1

next RF frequency. The PLL turn on time is

approximately

90 µs. The blanking interval

between

each

frequency

hop

then

approximately

us.

The

VCO

current

calibration result is available in FSCAL2 and is

not dependent on the RF frequency. Neither is

the charge pump current calibration result

available in FSCAL3. The same value can

therefore be used for all frequencies.

3) Run calibration on a single frequency at

startup. Next write 0 to FSCAL3[5:4] to

disable the charge pump calibration. After

writing to FSCAL3[5:4] strobe SRX (or STX)

with MCSM0.FS_AUTOCAL=1 for each new

frequency hop. That is, VCO current and VCO

capacitance calibration is done but not charge

pump current calibration. When charge pump

current calibration is disabled the calibration

time is reduced from approximately 720 µs to

approximately 150 µs. The blanking interval

between

each

frequency

hop

then

approximately 240 us

There is a trade off between blanking time and

memory space needed for storing calibration

data in non-volatile memory. Solution 2) above

gives

the

shortest

blanking

interval,

but

requires

memory

space

store

calibration

values.

Solution

gives

approximately 570 µs smaller blanking interval

than solution 1).

31.3

Wideband Modulation not Using

Spread Spectrum

Digital modulation systems under FCC part

15.247 includes 2-FSK and GFSK modulation.

A maximum peak output power of 1 W (+30

dBm) is allowed if the 6 dB bandwidth of the

modulated

signal

exceeds

500

kHz.

addition, the peak power spectral density

conducted to the antenna shall not be greater

than +8 dBm in any 3 kHz band.

Operating

high

data

rates

and

high

frequency separation, the

CC2500 is suited for

systems

targeting

compliance

with

digital

modulation systems as defined by FCC part

15.247. An external power amplifier is needed

to increase the output above +1 dBm.

31.4

Data Burst Transmissions

The high maximum data rate of

CC2500 opens

up for burst transmissions. A low average data

rate link (e.g. 10 kBaud), can be realized using

a higher over-the-air data rate. Buffering the

data and transmitting in bursts at high data

rate (e.g. 500 kBaud) will reduce the time in

active mode, and hence also reduce the

average

current

consumption

significantly.

Reducing the time in active mode will reduce

the likelihood of collisions with other systems,

e.g. WLAN.

31.5

Continuous Transmissions

In data streaming applications the

CC2500

opens up for continuous transmissions at 500

kBaud effective data rate. As the modulation is

done with a closed loop PLL, there is no

limitation in the length of a transmission.

(Open

loop

modulation

used

some

transceivers

often

prevents

this

kind

continuous data streaming and reduces the

effective data rate.)

CC2500-RTR1 数据表(PDF) 55 Page - Texas Instruments

CC2500-RTR1 数据表(HTML) 55 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96

数据表下载

链接网址

CC2500-RTR1 数据表(PDF) 55 Page - Texas Instruments

CC2500-RTR1 数据表(HTML) 55 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96

数据表 下载

链接网址

数据表下载