LICAL-ENC-MS001 Datasheet, PDF (6/7 Pages) List of Unclassifed Manufacturers – MS SERIES ENCODER DATA GUIDE

APPLICATION EXAMPLE
The MS encoder is ideal for registering button presses in remote control
applications. An example application circuit is shown in the figure below.
100k
100k
To Transmitter PDN
To Transmitter
220
1 _D6 LICAL-ENC-MS001 _D5 20
2 _D7
D4 ¹⁹
3 _{SEL_BAUD0}
D3 ¹⁸
4 _{SEL_BAUD1}
D2 ¹⁷
5 _GND
VCC ¹⁶
6 _GND
7 _GND
VCC
D1
15
14
8 _{TX_CNTL}
D0 ¹³
9 _{DATA_OUT}
10 _{MODE_IND}
SEND
CREATE_ADDR
12
11
100k
100k
100k
100k
100k
100k
220
100k
100k
Figure 7: MS Series Encoder Application Circuit
In this circuit, SPDT switches are used to select the baud rate so that pull-down
resistors are not needed. The data lines are connected to buttons and when any
button is pressed, the SEND line is pulled high and causes the encoder to
transmit. The diodes are used to prevent the voltage on one data line from
appearing on another data line.
If only one data line is needed, then it can be tied directly to the SEND line
without the need for the diodes.
None of the inputs have pull-up or pull-down resistors internally, so 100kΩ pull-
down resistors are used on the data lines, SEND, and CREATE_ADDR. These
resistors are used to pull the lines to ground when the buttons are not being
pressed and ensure that they are always in a known state and not floating.
Without these resistors, the state of the lines could not be guaranteed and
encoder operation may not be predictable.
A LED indicator is attached to the MODE_IND line to provide visual feedback to
the user that an operation is taking place. This line will source a maximum of
25mA, so the limiting resistor may not be needed, depending on the LED chosen
and the brightness desired.
Outgoing encoded data will be sent out of the DATA_OUT line at the baud rate
determined by the state of the SEL_BAUD lines. This line can be connected
directly to the DATA_IN line of a Linx transmitter, used to modulate an infrared
diode, or connected to any other serial transmission medium.
The TX_CNTL line is connected to the PDN line of a Linx transmitter so that the
module will enter a low power state when not in use. A LED can also be
connected to the TX_CNTL line to provide visual indication that the encoder is
sending data.
In this example, the data lines are pulled high by simple pushbutton switches, but
many other methods may be employed. Trace contacts, reed switches or
microcontrollers are just some examples of other ways of pulling the data lines
high. The flexibility of the encoder combined with the associative options of the
matching decoder opens a whole new world of options for creative designers.
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SYSTEM EXAMPLE
The first step in using the encoder is to set the baud rate using the SPDT
switches. Next, a unique Code Word is created by pressing and holding the
button connected to the CREATE_ADDR line for as long as desired. While the
button is held, the LED will be on indicating that the Code Word is being created.
Once the button is released, the LED will start flashing. The data buttons that the
encoder is to access are now pressed. Pressing the CREATE_ADDR button
again makes the encoder save the new Code Word and Control Permissions,
turn off the LED, and go to sleep.
The decoder must now learn the Code Word for the system to be operational.
Please see the decoder design guide for instructions on how to do this. The MS
Series Master Development System implements this system, so please see the
User’s Guide for the kit for more system information and circuit schematics.
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