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LICAL-DEC-HS001

HS SERIES DECODER DATA GUIDE

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TYPICAL APPLICATIONS

The HS Series is ideal for registering button presses in secure remote control

applications. An example application circuit of the decoder side is shown below.

10k

2.2k

100k

From Copy Input Port

100k

To Key Output Port

220

1 D6 LICAL-DEC-HS001 D5

2 D7

D4

3 SEL_BAUD

D3

4 SEND_COPY

D2

5 GND

VCC

6 GND

VCC

7 COPY_IN

D1

8 CREATE_KEY

9 KEY_OUT

D0

DATA_IN

10 MODE_IND

LEARN

20

19

18

17

16

15

14

13

12

11

100k

From Receiver

Figure 8: HS Series Decoder Application Circuit

In this circuit, the baud has been set for 2,400bps by pulling the SEL_BAUD line

to ground.

SEND_COPY, CREATE_KEY, and LEARN are all connected to buttons that will

pull the line high when pressed. Since the lines do not have internal resistors,

100kΩ resistors are used to pull the lines to ground when not in use.

COPY_IN is connected to a port that allows the transfer of the User Data from

another decoder. This port can be a simple wire, an infrared receiver, or any

other device that allows the transmission of asynchronous serial data.

The KEY_OUT line is connected to a port that allows the transfer of the key to

an encoder or another decoder. This port can be a simple wire, an infrared diode,

or any other device that allows the transmission of asynchronous serial data.

The KEY_OUT line can also be connected to a microprocessor or a PC to record

the transmitter identity. Application Note AN-00156 has sample C code that will

read the transmitter ID and display the ID number on an LCD screen.

A LED indicator is attached to the MODE_IND line to provide visual feedback

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.

The DATA_IN line is connected directly to the data output of the receiver.

Data Lines D0 through D7 can be connected directly to the external circuitry that

is to be activated remotely. In this example, D5 is connected directly to a

piezoelectric buzzer, which will cause the buzzer to sound when the D5 line on

the encoder goes high. Line D6 will activate a relay through a transistor buffer

when it goes high. A buffer like this may be needed if the decoder cannot source

enough current or voltage to energize the relay coil. The decoder will turn on the

transistor, which will provide the appropriate drive levels to the relay.

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TYPICAL SYSTEM SETUP

The HS Series offers an unmatched combination of features and security, yet is

easy for system designers and end users to operate. To demonstrate this, let’s

take a brief look at a typical user setup followed by more detailed design

information. The Typical Applications sections of the encoder and decoder data

guides show the circuit schematics on which these examples are based.

1. Create and exchange a key from a decoder to an encoder

The high security key is created and exchanged by placing the decoder in the

Create Key Mode. The decoder’s MODE_IND line LED will light to indicate that

the decoder has entered Create Key Mode. The decoder’s CREATE_KEY button

is then pressed ten times to create the key. After the tenth press, the MODE_IND

LED will turn off and the decoder will send the key out of the KEY_OUT line. The

MODE_IND LED on the encoder will light to indicate that the key has been

successfully transferred.

2. Establish Control Permissions

The user establishes what buttons on the encoder will be recognized by pressing

the decoder LEARN button. The decoder’s MODE_IND LED will start flashing

and the user presses the buttons that will be allowed access. Control

Permissions are stored when the LEARN button is pressed again or

automatically after 17 seconds.

There are other powerful options such as programming a user PIN or copying a

decoder but these simple steps are all that is required for a typical setup. It is

really that simple for a manufacturer or end user to setup the product!

DESIGN STEPS TO USING THE HS SERIES

Key creation and exchange from a decoder to an encoder

DATA OUT

2

DATA IN

KEY IN

4

MODE_IND

CREATE KEY BUTTON

3

LEARN BUTTON

SEND COPY BUTTON

1

KEY OUT

Figure 9: Steps to Exchange a Key

1. Provide a serial data connection from the decoder’s KEY_OUT line to the

encoder’s KEY_IN line. Typically this would be a wire, contact, or infrared.

2. Provide a serial data connection from the encoder’s DATA_OUT line to the

decoder’s DATA_IN line. Typically, this would be a wireless connection using a

transmitter and receiver combination.

3. On the decoder, set the LEARN line high and then the CREATE_KEY line high

to enter Create Key Mode. Take the LEARN line low, and toggle the

CREATE_KEY line high and low ten times to generate the key.

4. The encoder and decoder will automatically exchange the key using the

DATA_OUT / DATA_IN and KEY_OUT / KEY_IN lines. If the key exchange is

successful, the decoder and encoder MODE_IND lines will go high for 1 second.

Page 17

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