Serial interface commands
2400 baud RS232. 8 bit data, no parity, 1 start bit, 1 or 2 stop bits.
Serial data is sent to the unit on one of the parallel channel select pins (P0). It is very important that
the unit does not 'decode' switch bounce in ordinary operation as a command string, or spurious re-
writing of the e2prom will result. For this reason the user must send the 16 character string
ENABLESERIALMODE (followed by a carriage return) to activate the serial command mode before
sending any of the command strings listed below. Command mode is disabled on power down, or on
reception of a # character. To successfully program the unit, it must be enabled ('RXE high (rx) or TXE
low (tx)).
GOCHAN aa
LOAD aa nnnnn
SETPAR
SETSER
RVALUE rrrr
SINGLE nnnnn
Serially select channel aa, where aa is ch0 to ch31
Set value of N register for channel aa, where aa is Channels 0 to 31
Channel selected by 4 bit parallel inputs (ch0 to ch15 only)
Channel selected by most recent GOCHAN operation
Set value for R register
Set value of N for single channel operation.
N value NOT stored in EEPROM
<cr>
Process entry
/
Clear all buffers
#
Disable command mode
aa = a two digit channel number from 00 to 31
nnnnn = synthesizer N register value (up to 65535)
rrrr = synthesizer R register value (up to 16383)
For LMT1 Transmitter:
fXtal
10MHz
25kHz
R =
=
, So R=400
fchannelspacing
fRF
173.250MHz
NTX
=
=
= 6930
fChannelspacing
25kHz
For LMR1 Receiver:
fXtal
13MHz
25kHz
R =
=
, So R=520
fchannelspacing
fRF − 21.4MHz
173.250MHz − 21.4
25kHz
NRX
=
=
= 6074
fChannelspacing
Notes: 1. A pause of at least 50ms must be allowed between command strings (EEPROM
programming time).
2. SINGLE mode does not store the N value in EEPROM. Therefore the unit is
inoperative after a power down until either another valid SINGLE command is received,
or mode is changed by a GOCHAN, SETPAR or SETSER command. SINGLE mode is
intended for frequency agile applications.
3. For UK version (173.200 - 173.325MHz band) the following channel assignment is
supplied:
CH0: 173.250MHz
CH1: 173.275MHz
CH2: 173.300MHz
CH3: 173.325MHz
CH4 - CH7: 173.225MHz (only used for alarm applications)
CH8 - CH31: 173.325MHz
Radiometrix Ltd
LMT1/LMR1 Data Sheet
page 6
RADIOMETRIX [ RADIOMETRIX LTD ]
