TXE
pin 15
Active low enables transmitter. It has a 10kΩ pull-up to Vcc. (if used in RX only, tie this pin to +5v)
TXD
pin 14
This is a 5V CMOS logic level input. It can be directly interfaced to data output of a UART in a
microcontroller. TXD does not have an internal pull-up.
NC
pin 13
There is no pin in this position.
RXD
pin 12
This is a 5V CMOS logic level output. It can be directly interfaced to data input of a UART in a
microcontroller.
SETUP
pin 11
Pull low to enter test/setup mode. This is only sampled at power-up, and on tx>rx or rx>tx transitions. The
pullup only enables at these times.
Programming the RDL2
As supplied, the RDL2 is set to default channel zero. To change this preset, it is necessary to enter
setup/program mode.
The RDL2 is programmed through the same TXD / RXD pins that is used for sending/receiving data. An
RS232 terminal emulator (such as Aterm or HyperTerminal) is an ideal tool.
To connect to a true RS232 device, inverting RS232-CMOS level shifters must be used. Maxim MAX232 or
equivalent are ideal, but simple NPN transistor switches with pull-ups often suffice. With typical
microcontrollers and UARTs, direct connection is possible.
To enter program mode the SETUP pin (pin 11) must be held low at turn-on, or during a change of TXE pin
state. In this mode the radio link is disabled, but the TXD / RXD pins become a 9600 baud programming
interface. (Bytes received are echoed back on the RXD pin).
In 'setup' the unit will only respond to certain command strings:
CHAN0
to
CHAN4
<CR>:
These commands select one of 5 preset channels
A RDL2 will only communicate with a unit set to the same channel.
Channel number is stored in volatile memory. On power-up the RDL2 reverts to the default in EEPROM (as
supplied this is always Channel 0)
SETPROGRAM
<CR>:
Writes the current address and current channel into EEPROM as the new
default.
A tilda character (~, ascii 126dec) sent by the unit indicates end of
EEPROM write sequence
(these commands are normally only used for factory diagnostics)
NOTONE
<CR>:
Transmit unmodulated carrier
LFTONE
<CR>:
Transmit carrier modulated with 8KHz squarewave
HFTONE
<CR>:
Transmit carrier modulated with 16KHz squarewave
#
<CR>:
Transmitter off
A Carriage Return ‘<CR>’ (00Dhex) should be entered after each command sequence to execute it.
Releasing the SETUP pin to high state returns the RDL2 to normal operation.
Radiometrix Ltd
RDL2 Data Sheet
page 4
RADIOMETRIX [ RADIOMETRIX LTD ]
