Radiometrix Ltd

HMT2 Data Sheet

page 5

Version 2: programming instruction

The HMT2 provides 32 individually programmable channels

(As supplied, CH00-CH20 are programmed to 458.8 - 459.3MHz, and channels 21-31 are all set to

461.3MHz)

GOCHAN aa

Serially select channel aa, where aa is ch0 to ch31

TEMP aa

select channel aa, but revert to last GOCHAN value on next key-up

LOAD aa

nnnnn

Set value of N register for channel aa, where aa is Channels 0 to 31

RVALUE rrrr

Set value for R register

<cr>

Process entry

/

Clear all buffers

aa = a two digit channel number from 00 to 31 (and it MUST be two digits, so use "01" instead of "1".etc)

nnnnn = synthesizer N register value (up to 65535)

rrrr = synthesizer R register value (up to 16383)

18352

kHz

25

MHz

800

.

458

f

f

N

cing

Channelspa

RF

=

=

=

kHz

MHz

f

f

R

cing

channelspa

TCXO

25

13

=

=

, So R=520

Notes:

1.

A 2400 baud cmos level ‘inverted RS232 format’ (1 start bit, 8 data, 1or 2 stop bits, no parity) is

used.

2.

The unit echos all bytes sent back on the P3 output.

Following any successful operation, the bytes OK <cr> are also sent back, when the unit is ready.

3.

To successfully program the unit it must be in active state (txe low), so provision should be made to

force the unit into this state while programming (the third pin on the auxiliary programming connector

does this).

4.

All commands except the non-volatile TEMP aa initiate an e2prom programming sequence. 50mS

must be left before the next command is sent.

5.

These units employs a sub-set of the programming commands used by standard LMT module. (As

the P0 pin is dedicated to serial communication only, the ‘ENABLESERIALMODE’ command string is

NOT required.)