TXL2 [RADIOMETRIX]
UHF Multi Channel Transparent Data Link TX/RX; UHF多通道透明数据链路TX / RX
| 型号： | TXL2 |
| 厂家： | 
RADIOMETRIX LTD |
| 描述： | UHF Multi Channel Transparent Data Link TX/RX |
| 文件： | 总11页 (文件大小：593K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Radiometrix
Hartcran House, 231 Kenton Lane, Harrow, HA3 8RP, England
Tel: +44 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233
Issue 1, 30 April 2007
TXL2/RXL2
UHF Multi Channel Transparent Data Link TX/RX
The TXL2 and RXL2 modules are 9600baud
simplex multi channel OEM radio modems
in a Radiometrix SIL standard footprint,
operating on European 433MHz ISM band.
The TXL2/RXL2 pair act as a transparent
serial cable to attached host. Unlike raw
FM radio modules (e.g. TX2A/RX2A),
TXL2/RXL2 will take care of preamble,
synchronisation, bit balancing and error
checking along with automatic noise
squelching.
Figure 1: RXL2-433-9 radio modem receiver
The TXL2/RXL2 pair provides a one-way radio link. Provided no two devices attempt to transmit
simultaneously no further restrictions on data transmission need be made, as all transmit timing, valid
data identification and datastream buffering is conducted by the units. Synchronisation and framing
words in the packet prevent the receiver outputting garbage in the absence of wanted RF signal or
presence of interference. For multiple radio systems a TXL2/RXL2 can be set to 1 of 8 unique addresses.
As well as having unique addresses, the TXL2/RXL2 allow operation on one of 5 pre-set frequencies in
the 433MHz band. These frequencies are non-overlapping and simultaneous operation of TXL2/RXL2
pairs in the same area on different channels will be possible. Units are supplied on 433.925MHz (Ch0)
as default.
Features
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Conforms to EN 300 220-3 and EN 301 489-3
High quality, stable crystal reference
Low noise synthesiser / VCO
SAW front-end filter
Multi-stage ceramic IF filtering
Single conversion superhet
Serial modem baud rate at 9600bps (simplex)
Addressable point-to-point
5 serial select wideband channels
Applications
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PDAs, organisers & laptops
Handheld / portable terminals
EPOS equipment, barcode scanners
In-building environmental monitoring and control
Remote data acquisition system, data logging
Fleet management, vehicle data acquisition
Technical Summary
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Operating frequency: 433.925MHz (default)
Modulation: 16kbps bi-phase FSK
Supply: 5V at 28mA transmit, 22mA receive/idle
Transmit power: +10dBm (10mW)
Receiver sensitivity: -107dBm (for 1% BER)
32 byte data buffer
Adjacent channel rejection: 60db @ ±320kHz
Receiver Blocking: >75dB
Radiometrix Ltd
TXL2/RXL2 Data Sheet
page 1
Radiometrix Ltd
TXL2/RXL2 Data Sheet
page 2
42mm
7mm
18mm
TXL2
15.24mm (0.6")
4
0.3"
1 = RF gnd
2 = RF out
3 = RF gnd
4 = En
6
1
2
5
3
7
8
5 = Vcc
6 = GND
7 = TXD
8 holes of 0.7mm dia.
pin spacing 2.54mm (0.1")
8 = SETUP
Figure 3: TXL2 footprint
TXL2 Pin description
Pin
1
2
Name
RF GND
RF out
Function
RF ground
50Ω RF output to the antenna
RF ground
3
RF GND
4
5
6
7
8
EN
Pull high to enable module (may be tied to Vcc)
5V regulated power supply (4.75 – 5.25V)
Supply ground
Vcc
GND
TXD
Inverted RS232 input (5V CMOS logic, No pullup)
TEST/SETUP Pull low to enter test/setup mode (5V CMOS logic, Pullup to 5V)
Notes:
1. TEST has 47K pullup to Vcc. TXD has none. EN has a 47K pulldown
2. Vcc must be a 5v regulated supply (4.75 - 5.25v)
3. Pinout is similar to TX1H, with the addition of pin 8 (located 7.62mm on from pin 7)
4. TXD is inverted RS232 at 5v cmos levels. To connect to a true RS232 device, inverting a level shifter must be
used (MAX232 type are ideal, but simple NPN transistor switches with pullups often suffice). With typical
microcontrollers and uarts, direct connection is possible.
5. The TXL2 provides transmit side of a simplex link, but provided no two devices attempt to transmit at one
time, no further restrictions on data transmission need be made, as all transmit timing, valid data identification
and datastream buffering is conducted by the unit. There is no 'transmit enable' pin.
6. This unit is compatible with the RXL2 receiver and the TDL2A transceiver
7. A simple addressing structure is included in the datastream. Units may be programmed onto one of eight
addresses (all units are supplied set to default ADDR=0 and default channel=0, 433.925MHz)
Radiometrix Ltd
TXL2/RXL2 Data Sheet
page 3
Radiometrix Ltd
TXL2/RXL2 Data Sheet
page 4
47mm
7mm
17mm
RXL2
30.48mm (1.2")
1 = RF in
2 = RF gnd
3 = RSSI/BUSY
4 = 0V
1
2
3
4
5
6
7
5 = Vcc
6 = AF/PGM
7 holes of 0.7mm dia pin spacing 2.54mm (0.1")
Figure 5: RXL2 footprint
RXL2 Pin description
Pin
1
2
Name
RF in
RF GND
Function
50Ω RF input from the antenna
RF ground
3
4
5
6
7
RSSI/BUSY S meter or BUSY output
0V
Supply ground
Vcc
AF/PGM
RXD
5V regulated power supply (4.75 – 5.25V)
Baseband audio (or PGM in)
Receive Data (Inverted RS232 at 5V CMOS logic level); Input in
PGM mode
Notes:
1. To enter program mode, the AF/PGM pin must be tied to ground (Vpin below 0.3v: jumper or open collector
recommended). Normally this pin functions as a high impedence (20K) receiver baseband audio output
2. Vcc must be a 5v regulated supply (4.75 - 5.25v)
3. Pinout is as RX2A
4. RXD is inverted RS232 at 5v cmos levels. To connect to a true RS232 device, inverting level shifters must be
used (MAX232 type are ideal, but simple NPN transistor switches with pullups often suffice). With typical
microcontrollers and uarts, direct connection is possible. The same pin is uesd for normal operation Data out,
PGM mode data in, and PGM mode data out.
5. The RXL2 provides a receive side of a simplex link. Provided no two devices attempt to transmit at one time,
no further restrictions on data transmission need be made, as all transmit timing, valid data identification and
datastream buffering is conducted by the unit.
6. This unit is compatible with the TXL2 transmitter and the TDL2A transceiver.
7. A simple addressing structure is included in the datastream. Units may be programmed onto one of eight
addresses (all units are supplied set to default addr=0) and one of five RF channels (supplied default is
channel=0, 433.925MHz)
8. RSSI pin can be changed to a 'BUSY' (= valid data in FIFO) logic output by a solder blob link on the back of
the pcb, otherwise it functions as a signal strength output (0 - 1.4v)
Radiometrix Ltd
TXL2/RXL2 Data Sheet
page 5
Condensed specifications
Frequency
433.925MHz – CHAN0 (default channel)
433.285MHz – CHAN1
433.605MHz – CHAN2
434.245MHz – CHAN3
434.565MHz – CHAN4
Frequency stability
Channel width
Number of channels
±10kHz
320kHz
1 of 5, user programmed
Supply Voltage
5V
Current
TXL2: 25mA transmit, 8mA idle (EN active / high, no activity on TXD)
RXL2: 22mA receive/idle
Operating temperature
Spurious radiations
-20 °C to +70 °C (Storage -30 °C to +70 °C)
Compliant with ETSI EN 300 220-3 and EN 301 489-3
Interfaces
Size
0.1" pitch SIL pins
TXL2: 43 x 19 x 7 mm
RXL2: 47 x 17 x 7 mm
TXL2 Transmitter
Output power
TX on switching time
Modulation type
FM peak deviation
10dBm (10mW) ±1dB
<4ms
16kbps bi-phase FSK
+/-25KHz
Adjacent channel TX power
TX spurious
<-37dBm
<-45dBm
RXL2 Receiver
Sensitivity
image
-107dBm for 1% BER
-50dB
spurious / adjacent channel
Blocking
LO re-radiation
-65dB
-84dB nominal, 75dB worst case
<-60dBm
Interface
Data rate
Format
Levels
Buffers
9600baud, Simplex
1 start, 8 data, 1 stop, no parity
5V CMOS (inverted RS232. Mark = 5V = idle)
32 byte FIFO
Flow control
Addressing
None
1 of 8, user programmed
Data latency
14ms (first byte into TX, to first byte out of RX)
Radiometrix Ltd
TXL2/RXL2 Data Sheet
page 6
Serial interface – modem operation
To connect to a true RS232 device, inverting RS232-CMOS level shifters must be used. Maxim MAX232
or equivalent are ideal, but simple NPN transistor switches with pull-ups often suffice. With typical
microcontrollers and UARTs, direct connection is possible.
The Radio / data stream interface
A 32 byte software FIFO is implemented in both the transmit and receive sub-routine. At the
transmitting end this is used to allow for the transmitter start up time (about 3mS), while on receiving
end it buffers arriving packets to the constant output data rate. All timing and data formatting tasks
are handled by the internal firmware. The user need not worry about keying the transmitter before
sending data as the link is entirely transparent.
For transmission across the radio link data is formatted into packets, each comprising 3 bytes of data
and a sync code. If less than 3 bytes are in the transmit end FIFO then a packet is still sent, but idle
codes replaces the unused bytes. When the transmit end FIFO is completely emptied, then the
transmitter is keyed off.
Operation: Radio interface.
Raw data is not fed to the radios. A coding operation in the transmit sub-routine, and decoding in the
receiver, isolate the AC coupled, potentially noisy baseband radio environment from the datastream.
The radio link is fed a continuous tone by the modem. As in bi-phase codes, information is coded by
varying the duration consecutive half-cycles of this tone. In our case half cycles of 62.5us and 31.25us
are used. In idle (or 'preamble') state, a sequence of the longer cycles is sent (resembling an 8KHz tone).
A packet comprises the Synchronising (or address) part, followed by the Data part, made up of twelve
Groups (of four half cycles duration). Each Group encodes 2 data bits, so one byte is encoded by 4
Groups.
Figure 6: transmitted and received data
Radiometrix Ltd
TXL2/RXL2 Data Sheet
page 7
The oscilloscope screen capture shows a single byte being transmitted by TXL2. A BiM2-433-64
transceiver is used to capture the transmitted data The character appears on the serial data output
(RXD) pin of the RXL2 after about 12.5ms. Busy (STATUS) pin is momentarily set high to indicate the
presence of a valid data in the receive buffer of the RXL2.
It can be clearly seen that unlike raw radio modules, RXL2 does not output any noise when there is not
any transmission. Data fed into the TXD input of a TXL2 transmitter appears at the RXD output of a
RXL2 receiver within radio range in the original form it was fed.
Figure 7: 16kbps Bi-phase encoded continuous data stream (expanded view)
Continuous serial data at 9600bps (above) is encoded as half-cycles of 8kHz (62.5µs long bit) and 16kHz
(31.25µs short bit).
Programming the TXL2/RXL2
In order to use all the functions embedded in the TXL2/RXL2, the user must be aware of the
setup/programming facility, which allow different addresses and frequency channels to be set up, and if
necessary accesses diagnostic test modes.
Both modules are is programmed through the same RS232 port that is used for sending/receiving data.
An RS232 terminal emulator (such as Aterm or HyperTerminal) is an ideal tool.
TXL2 and RXL2 can be put to program mode by pulling the TEST and PGM pins respectively.
The unit will only respond to certain command strings:
ADDR0 to ADDR7 <CR>:
CHAN0 to CHAN4 <CR>:
These commands set up one of 8 unique addresses.
These commands select one of 5 preset channels
A TXL2 will only communicate with an RXL2 unit set to the same address and the same channel.
Address and channel numbers are stored in volatile memory. On power-up both will revert to the
default in EEPROM (as supplied this is always address 0 and Channel 0)
SETPROGRAM <CR>:
Writes the current address and current channel into EEPROM as the
new default.
A tilda character (~, ascii 126dec) sent by the unit indicates end of
EEPROM write sequence
Radiometrix Ltd
TXL2/RXL2 Data Sheet
page 8
(these commands are normally only used for factory diagnostics)
NOTONE <CR>:
LFTONE <CR>:
HFTONE <CR>:
# <CR>:
Transmit unmodulated carrier
Transmit carrier modulated with 8KHz squarewave
Transmit carrier modulated with 16KHz squarewave
Transmitter off
A Carriage Return ‘<CR>’ (00Dhex) should be entered after each command sequence to execute it.
Releasing the TEST and PGM pins to high state return the modules to normal operation.
Application circuits
Interfacing a microcontroller to TXL2/RXL2
Figure 8: TXL2 and RXL2 interfaced directly to a microcontroller
TXL2 and RXL2 can be directly interfaced to any microcontrollers. If the microcontroller has a built-in
UART, it can concentrate on its main task and leave the packet formatting, bit balancing and error
checking of serial data to TXL2/RXL2.
Serial data should be in the following format:
1 start bit, 8 data bits, no parity, 1 or 2 stop bits
9600bps
0V=low, 5V=high
BUSY pin (in RXL2) can be connected to one of the port pins which can generate an interrupt on low-to-
high transition (e.g. RB0/INT pin in the PIC). This can be used to enter a receive sub-routine to
download data received from remote TXL2. Therefore, the host does not need to wait in a loop for a
packet.
Interfacing RS232 port to TXL2/RXL2
Figure 9: TXL2/RXL2 interfaced to an RS232 port via an RS232 line driver/receiver
Some DTE hosts assert DTR signal when they are active and this can be used via RS232 line receiver to
enable TXL2. Otherwise the ENABLE must be physically pulled-low to activate the TXL2.
Radiometrix Ltd
TXL2/RXL2 Data Sheet
page 9
Antenna requirements
Three types of integral antenna are recommended and approved for use with the module:
A) Whip
This is a wire, rod ,PCB track or combination connected directly to RF pin of the
module. Optimum total length is 16cm (1/4 wave @ 433MHz). Keep the open circuit (hot)
end well away from metal components to prevent serious de-tuning. Whips are ground
plane sensitive and will benefit from internal 1/4 wave earthed radial(s) if the product is
small and plastic cased
B) Helical
C) Loop
Wire coil, connected directly to RF pin, open circuit at other end. This antenna is very
efficient given it’s small size (20mm x 4mm dia.). The helical is a high Q antenna, trim
the wire length or expand the coil for optimum results. The helical de-tunes badly with
proximity to other conductive objects.
A loop of PCB track tuned by a fixed or variable capacitor to ground at the 'hot' end and
fed from RF pin at a point 20% from the ground end. Loops have high immunity to
proximity de-tuning.
A
whip
***
***
*
B
helical
**
C
loop
*
Ultimate performance
Easy of design set-up
Size
**
*
***
**
**
***
Immunity proximity effects
*
The antenna choice and position directly controls the system range. Keep it clear of other metal in the
system, particularly the 'hot' end. The best position by far, is sticking out the top of the product. This is
often not desirable for practical/ergonomic reasons thus a compromise may need to be reached. If an
internal antenna must be used, try to keep it away from other metal components, particularly large
ones like transformers, batteries and PCB tracks/earth plane. The space around the antenna is as
important as the antenna itself.
0.5 mm enameled copper wire
close wound on 3.2 mm diameter former
RF
433 MHz = 24 turns
A. Helical antenna
Feed point 15% to 25% of total loop length
track width = 1mm
4 to 10 cm2 inside area
RF-GND
C2
C1
RF
C3
C4
B. Loop antenna
16.4cm
wire, rod, PCB-track or a combination
of these three
RF
433 MHz = 16.4 cm total from RF pin.
C. Whip antenna
Figure 10: Antenna types
Ordering information
The TXL2/RXL2 modems are manufactured in the following variants as standard:
Part Number
TXL2-433-9
RXL2-433-9
TXL2-433-4
RXL2-433-4
Radiometrix Ltd
Frequency band
Maximum baud rate
9.6kbps
433.925 - 434.565 MHz
433.925 - 434.565 MHz
433.925 - 434.565 MHz
9.6kbps
4.8kbps
433.925 – 434.565 MHz 4.8kbps
TXL2/RXL2 Data Sheet
page 10
Radiometrix Ltd
Hartcran House
231 Kenton Lane
Harrow, Middlesex
HA3 8RP
ENGLAND
Tel: +44 (0) 20 8909 9595
Fax: +44 (0) 20 8909 2233
sales@radiometrix.com
www.radiometrix.com
Copyright notice
This product data sheet is the original work and copyrighted property of Radiometrix Ltd. Reproduction in whole or
in part must give clear acknowledgement to the copyright owner.
Limitation of liability
The information furnished by Radiometrix Ltd is believed to be accurate and reliable. Radiometrix Ltd reserves the
right to make changes or improvements in the design, specification or manufacture of its subassembly products
without notice. Radiometrix Ltd does not assume any liability arising from the application or use of any product or
circuit described herein, nor for any infringements of patents or other rights of third parties which may result from
the use of its products. This data sheet neither states nor implies warranty of any kind, including fitness for any
particular application. These radio devices may be subject to radio interference and may not function as intended if
interference is present. We do NOT recommend their use for life critical applications.
The Intrastat commodity code for all our modules is: 8542 6000.
R&TTE Directive
After 7 April 2001 the manufacturer can only place finished product on the market under the provisions of the
R&TTE Directive. Equipment within the scope of the R&TTE Directive may demonstrate compliance to the
essential requirements specified in Article 3 of the Directive, as appropriate to the particular equipment.
Further details are available on The Office of Communications (Ofcom) web site:
http://www.ofcom.org.uk/radiocomms/ifi/
Information Requests
European Radiocommunications Office (ERO)
Peblingehus
Ofcom
Riverside House
Nansensgade 19
2a Southwark Bridge Road
London SE1 9HA
DK 1366 Copenhagen
Tel. +45 33896300
Fax +45 33896330
ero@ero.dk
Tel: +44 (0)845 456 3000 or 020 7981 3040
Fax: +44 (0)20 7783 4033
information.requests@ofcom.org.uk
www.ero.dk
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