Radiometrix Ltd

LMT1/LMR1 Data Sheet

page 5

Pin description – LMR1

Pin

Name

Function

1a

Vcc

3.1 – 15V power supply

2a

0V

Ground

3a

RXE

Receiver Enable (active high)

4a

RXD

Data out (open collector, no pullup)

5a

AF out

700mV p-p audio. DC coupled, approx 0.8v bias.`

1b

P0/PGM

Parallel Channel select LSB

2b

P1

Parallel Channel select

3b

P2

Parallel Channel select

4b

P3

Parallel Channel select MSB

5b

RSSI

DC level between 0.5v and 2.2v. 60dB dynamic range

NOTES:

1. Serial programming is by an inverted, cmos logic level, 2400 baud RS232 datastream applied to

the P0 pin.

2. Channel select inputs have pullups (50k

Ω) to 3v internal rail. Do not exceed 3v logic levels on

this port.

3. Channel select inputs are active low

4. All pins are on an 0.1" grid

5. Data recovery circuit used for RXD is not a simple 'average and compare' type. It is a peak

sampling quasi-DC coupled design, allowing a greater than usual flexibility in data format.

6. Unit will operate (with marginally reduced specifications) from a 3.0v rail. This must be well

regulated and without noise or ripple, as in this state the unit's internal regulator no longer

operates, and provides no supply rejection.

Figure 5: LMR1 footpint (top view)