LMT2-458-10 Просмотр технического описания (PDF) - Radiometrix Ltd

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LMT2-458-10

UHF Narrow Band FM Low Cost multi channel radio modules

Radiometrix Ltd 

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

<cr>

/

#

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

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)

N TX

=

f RF

f Channelspacing

= 433.900MHz = 17356

25kHz

R = fTCXO = 13MHz , So R=520

f channelspacing 25kHz

N RX

=

f RF − 21.4MHz

f Channelspacing

= 433.900MHz − 21.4 = 16500

25kHz

Note:

A pause of at least 50ms must be allowed between command strings (EEPROM

programming time).

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.

Radiometrix Ltd

LMT2/LMR2 Data Sheet

page 6

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