LICAL-ENC-HS001 Linx Technologies Inc, LICAL-ENC-HS001 Datasheet - Page 7

• Manufacturer Part Number: LICAL-ENC-HS001
• Description: IC ENCODER HS SERIES 20-SSOP
• Manufacturer: Linx Technologies Inc
• Series: HSr
• Type: Encoderr

Specifications of LICAL-ENC-HS001

• Package / Case: 20-SSOP
• Applications: RF, IR
• Mounting Type: Surface Mount
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

TYPICAL APPLICATION
Figure 8: HS Series Encoder Application Circuit
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The HS Series encoder is ideal for registering button presses in secure remote
control applications. An example application circuit is shown below.
In this example, 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.
Diodes are used to prevent the voltage on one data line from affecting another.
The KEY_IN line is attached to a port that allows the key to be transferred from
the decoder during setup. To ensure security, this would normally be a wire,
contact, or short range IR link, although any connection capable of transferring
asynchronous serial data may be utilized.
None of the inputs have pull-up or pull-down resistors internally, so 100kΩ pull-
down resistors are used on the data, SEND, and CREATE_PIN lines. These
resistors are used to pull the lines to ground when the buttons are not being
pressed, which ensures that the pins are always in a known state and not
floating. Without these resistors, the state of the lines cannot be guaranteed and
encoder operation may not be predictable.
A LED 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. A LED can also be connected to the TX_CNTL line to provide
visual indication that the encoder is sending data.
Outgoing encrypted data will be sent via the DATA_OUT line at the baud rate
determined by the state of the SEL_BAUD line. In the circuit above, the baud has
been set for 4,800bps by pulling it to ground. The DATA_OUT line can be
connected directly to the DATA_IN line of a Linx transmitter or other wireless
device.
The TX_CNTL line may be connected to the PDN line of a Linx transmitter so
that the module will enter a low power state when not in use.
In this example, the data lines are pulled high by simple pushbutton switches, but
many other methods may be employed. Contacts, reed switches, or
microcontrollers are just some examples of other ways to pull the data lines high.
The flexibility of the encoder, combined with the associative options of the
matching decoder, opens a new world of options for creative product designers.
From Key Input Port
To Transmitter PDN
To Transmitter
220
100k
100k
10
1
2
3
4
5
6
7
8
9
D6
D7
SEL_BAUD
SEL_TIMER
GND
GND
KEY_IN
TX_CNTL
DATA_OUT
MODE_IND
LICAL-ENC-HS001
CREATE_PIN
SEND
VCC
VCC
D5
D4
D3
D2
D1
D0
20
19
18
17
16
15
14
13
12
11
100k
100k
100k
100k
100k
100k
100k
100k
220
TYPICAL SYSTEM SETUP
DESIGN STEPS TO USING THE HS SERIES
Figure 9: Steps to Exchange a Key
1. Create and exchange a key from a decoder to an encoder
2. Establish Control Permissions
Key creation and exchange from a decoder to an encoder
1. Provide a serial data connection from the decoder’s KEY_OUT line to the
2. Provide a serial data connection from the encoder’s DATA_OUT line to the
3. On the decoder, set the LEARN line high and then the CREATE_KEY line high
4. The encoder and decoder will automatically exchange the key using the
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.
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.
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!
encoder’s KEY_IN line. Typically this would be a wire, contact, or infrared.
decoder’s DATA_IN line. Typically, this would be a wireless connection using a
transmitter and receiver combination.
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.
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.
KEY IN
DATA OUT
1
2
3
4
KEY OUT
CREATE KEY BUTTON
LEARN BUTTON
SEND COPY BUTTON
MODE_IND
DATA IN
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