Linx Technologies MDEV-xxx-HH-KF-MS - Manual (Page 5)

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The Decoder Board
The decoder board included with the evaluation kit uses the LR Series
receiver to receive the signal from the Keyfob transmitter and then
feeds it into the MS Series decoder. The board is designed to allow full
access to the many features of the decoder and to speed development
and integration of the LR and MS into a product. The following sections
describe the features of this board in detail.
The Prototyping Area
The prototyping area on the decoder board contains a large area of plated
through-holes so that external circuitry can be placed on the board.
This circuitry can be interfaced with the MS Series decoder through the
breakout header to the right of the holes. At the bottom of this area is a row
connected to the 3V power supply and at the top is a row connected to
ground.
All of the data lines are connected to a wire-wrap header to the right,
allowing easy access from the prototyping area. The Decoder Data and
TX ID lines are also available on the header as well as the PDN line from
the RF module. This allows complete control of the entire system from the
prototyping area, giving the designer a great deal of flexibility in using the
board.
The Power Supply
The power supply on the decoder board consists of a standard 9V battery
and power jack connected to a 3.0V voltage regulator. It can provide
approximately 500mA of current to the prototyping area, so if the added
circuitry needs more than this, the designer must add an external supply.
If the circuit consistently draws more than 100mA of current, it might be
better to use the power jack rather than the battery, as the battery may run
down fairly quickly, reducing testing and development time.
The jack accepts a standard 5.5mm plug with the tip ground and the outer
shell 7 to 16VDC positive supply. While a reverse voltage protection diode
has been included on the board to protect the circuitry in case the voltage
on the plug is reversed, it is still a good idea to double-check the polarity.
Setting the Transmitter Address
The address is changed by using a paper clip
or probe to press the CREATE_ADDR button
on the board through the hole in the back
of the case. When the button is depressed,
an LED lights up on the front of the keyfob,
indicating that the address is being created.
The address is randomized for as long as
the button is held down. When the button is
released, the randomized address is saved
and the LED begins flashing to indicate that
the Control Permissions may now be set.
Press the buttons that the Keyfob user will have the authority to access.
Press the CREATE_ADDR button with the paper clip again or wait 17
seconds for it to time out. The address and Control Permissions are
now set. The decoder needs to learn the address before it accepts any
transmissions. Please see the MS Series Decoder Data Guide for details.
Button Assignments
The Keyfob is available in five button configurations. Those configurations
and the corresponding switch numbers are shown in Figure 5. The table
shows which encoder data line has been assigned to each switch. When a
button is pressed, the data line goes high, causing the corresponding data
line on the decoder to go high if the address has been learned.
Figure 4: CREATE_ADDR Button Access
S4
S2
S1 S3 S5
S5
S2
S5
S4 S4
S2
S4
S1 S3
S2
Button Data Line
S1 D0
S2 D1
S3 D2
S4 D3
S5 D4
Figure 5: OTX-***-HH-KF#-MS Button Assignments
CREATE_ADDR
Button Access