Radiometrix Ltd

USX2 Data Sheet

page 3

Figure 3: Provisional USX2 footprint (Top)

Pin Description

NOTES:

1.

No inversion occurs between TXD and RXD. However AF out is inverted relative to TXD.

2.

Parallel channel selects (P0-P3) and TXE are active LOW and have 47k

internal pullups to 3V

3.

Open collector output RXD has a 47 k

pullup to 3V.

4.

The software incorporates a 1200 baud modem, compatible with that implemented in other Radiometrix

narrowband units ( i1200 tones and format ). Modem operation is selected by serial command.

5.

Main serial port (P0, P3) operates at 9600 baud. (Command set is not the same as TR2M, SMX

families). The unit is capable of operating in 'basic' parallel channel select only mode, or in serial

controlled 'expanded' mode

6.

Transmit power can be set by serial command

7.

RSSI can be read back as a digital value. (on P3)

8.

If analogue transmit modulation is needed, then connect a series 1 F cap + 500k

trimmer (a multiturn

is advised) in the TXD circuit. Adjust trimmer for 90% of peak deviation (+/- 2.7KHz) at mean input level.

Pins

Normal mode

Serial mode

Modem mode

1A

RF Gnd

RF ground

2A

RF in/out

To the antenna

3A

RF Gnd

RF ground

1

TXD

DC coupled input for TTL/ CMOS logic

NC

2

TXE

Transmit enable.

Low = RX mode. High = TX. (10k

pull down)

NC

3

GND

(0V)

4

Vcc

DC supply input (3.6 –15V)

5

P3

Parallel channel select MSB

Serial read back

BUSY

6

P2

Parallel channel select

TBA

MOD TXD

7

P1

P1 - Parallel channel select

TBA

MOD RXD

8

P0

P0 - Parallel channel select LSB

PGM in

PGM in

9

RSSI

DC level between 0.5V and 2.5V. 60dB

dynamic range

10

RXD

Open collector output of data slicer

NC

11

AF out

500mV p-p audio. DC coupled, approx 0.8V

bias

NC