HIGH-PERFORMANCE LS SERIES ENCODER/DECODER WIRELESS MADE SIMPLE ® LS SERIES ENCODER / DECODER DATA GUIDE DESCRIPTION The Linx LS Series encoders and decoders provide an extremely simple, yet reliable, protocol for the transmission of switch closures or button contacts. This series can find use in any basic, low-cost remote control application. Simply take a data line high on the encoder and a corresponding line will go high on the decoder. No programming or addressing is required, making integration of the LS extremely easy while maintaining a robust link. 0.313 (7.04) 0.250 (6.35) 0.373 (9.46) 0.012 (0.29) 10˚ 0.370 (9.40) 10˚ 0.130 (3.30) 0.155 (3.94) 0.015 (0.38) FEATURES No addressing or programming Easy to use Very low current consumption Four data lines Easy serial interface Selectable baud rates High noise immunity Standard PDIP package 0.130 (3.30) 0.058 (1.46) 0.018 (0.46) 0.100 (2.54) Figure 1: Package Dimensions 0.313 (7.94) 0.100 (2.54) APPLICATIONS INCLUDE Range Testing Simple Remote Control Wire Elimination Remote Status Monitoring Lighting Control 0.018 (0.46) Figure 2: PCB Layout Dimensions ORDERING INFORMATION PART # DESCRIPTION LICAL-ENC-LS001 LS Encoder LICAL-DEC-LS001 LS Decoder LS encoders / decoders supplied in tubes of 60 pcs. All parts are RoHS compliant. Revised 1/28/08 ELECTRICAL SPECIFICATIONS Parameter POWER SUPPLY Operating Voltage Supply Current: At 2.0V VCC At 3.0V VCC At 5.0V VCC Power-Down Current: At 2.0V VCC At 3.0V VCC At 5.0V VCC ENCODER / DECODER SECTION Input Low Input High Output Low Output High Input Sink Current Output Drive Current ENVIRONMENTAL Operating Temperature Range PIN ASSIGNMENTS Designation Min. Typical Max. Units Notes VCC ICC 2.0 – 5.5 VDC – – – – 340 500 800 450 700 1,100 µA µA µA 1 1 1 – – – 0.99 1.2 2.9 700 770 995 nA nA nA VIL VIH VOL VOH – – 0.0 0.8 x VCC – VCC - 0.7 – – – – – – – – 0.15 x VCC VCC 0.6 – 25 25 V V V V mA mA – -40 – +125 °C IPDN 2 3 Table 1: Electrical Specifications LICAL-ENC-LS001 1 GND VCC 2 D0 DATA_OUT 3 D1 D3 4 D2 SEL_BAUD 8 7 6 5 LICAL-DEC-LS001 1 GND VCC 2 D0 DATA_IN 3 D1 D3 4 D2 SEL_BAUD 8 7 6 5 Figure 3: LS Series Encoder and Decoder Pin Assignments ENCODER PIN ASSIGNMENTS Notes 1. Current consumption with no active loads. 2. For 3V supply, (0.15 x 3.0) = 0.45V max. 3. For 3V supply, (0.8 x 3.0) = 2.4V min. Pin Name ABSOLUTE MAXIMUM RATINGS Supply Voltage VCC Any Input or Output Pin Max. Current Sourced By Data Pins Max. Current Sunk By Data Pins Max. Current Into VCC Max. Current Out Of GND Operating Temperature Storage Temperature -0.3 -0.3 -40 -65 to +6.5 to VCC + 0.3 25 25 250 300 to +125 to +150 VDC VDC mA mA mA mA °C °C Pin Number I/O Description VCC 1 — Positive Power Supply DATA_OUT 2 O Serial Data Output SEL_BAUD 4 I Baud Rate Selection Pin GND 8 — Ground 3, 5, 6, 7 I Data Input Pins Pin Number I/O Description VCC 1 — Positive Power Supply DATA_OUT 2 I Serial Data Input SEL_BAUD 4 I Baud Rate Selection Pin GND 8 — Ground 3, 5, 6, 7 O Data Output Pins D0-D3 DECODER PIN ASSIGNMENTS *NOTE* Exceeding any of the limits of this section may lead to permanent damage to the device. Furthermore, extended operation at these maximum ratings may reduce the life of this device. *CAUTION* This product is a static-sensitive component. Always wear an ESD wrist strap and observe proper ESD handling procedures when working with this device. Failure to observe this precaution may result in device damage or failure. Pin Name D0-D3 Page 2 Page 3 PIN DESCRIPTIONS DECODER OPERATION VCC The LS Series decoder begins by waiting for the DATA_IN line to transition from low to high. At that point, the decoder will accept the data, check it for errors, and confirm that the bytes are valid. If the data pass all of the checks, then the data bits are output on the decoder’s data lines. If any of these checks fail, then the decoder will ignore the received packet and look for the next one. This is the positive power supply. DATA_OUT The encoder will output a serial data stream on this line. DATA_IN The decoder will monitor this line for data. SEL_BAUD This line is used to select the baud rate of the serial data stream. The state of the line allows the selection of one of two possible baud rates, as shown in the adjacent table. SEL_BAUD Baud Rate (bps) 0 2,400 1 9,600 Table 2: Baud Rate Selection Table GND These lines are connected to ground. Data Lines The LS Series has three data lines, D0 through D3. When any of these lines goes high on the encoder, their states are recorded, encoded for transmission, and then reproduced on the outputs of the decoder. PRODUCTION CONSIDERATIONS LS Series encoders and decoders are implemented in an industry standard 8Lead Plastic Dual In-Line Package (8-PDIP). The package and layout dimensions are shown on Page 1. These components are leaded through-hole parts and may be hand- or wave-soldered. THEORY OF OPERATION The Linx LS Series encoder and decoder are designed to register button presses or contact closures. When a pin goes high on the encoder, a signal is sent to make a corresponding pin go high on the decoder. The outputs of the decoder can then be used to activate almost anything, from driving a LED or buzzer to activating digital circuitry. The LS Series does not require any programming or addressing and its simplicity makes it a good choice for basic remote control devices that are designed to turn something on and off. ENCODER OPERATION Upon power-up, the encoder enters sleep mode. As soon as one of the data lines goes high, it will wake up and begin the transmit process. First, the encoder will record the state of the data lines, encode for error correction, and assemble the packet. It will then output the packet on the DATA_OUT line. The encoder will repeat the transmission process for as long as one of the data lines is high, otherwise it will go back to sleep. It will update the state of the data lines with each packet, and it will finish the current transmission even if all of the lines are pulled to ground. Page 4 The decoder has a built-in debounce circuit to guard against signal cutout. This is a timer that maintains the current state of the data lines until changed by a valid packet or until no valid packets are received for 131mS. After 131mS, the decoder pulls all of the data lines to ground and goes back to sleep. This helps protect devices attached to the decoder by smoothing out the output response. Rapid switching resulting from lost packets could cause damage to devices, such as relays or motors, that may be controlled by the decoder. This debounce circuit helps in noisy environments and at the range limit of the link where lost packets and cutouts are more frequent. The drawback is that there is a 131mS lag time between the end of the transmission and when the data lines are turned off. This is generally not a problem with manual remote control applications, but must be taken into account in applications where timing is critical. TYPICAL APPLICATIONS LS Series encoders and decoders would typically be used in remote control applications to register button presses and activate circuitry in a remote device. Figure 4 shows an example application circuit. An SPDT switch is used in both circuits to set the baud rate. This switch will pull the BAUD_SEL line to either ground or VCC for selection of one of the baud rates listed in the Pin Descriptions section. The baud rate on both sides must match in order for the encoder and decoder to correctly operate. Two pushbutton switches are connected to the data lines on the encoder. Since none of the data lines have internal pull resistors, external resistors are used to pull the data lines to ground when not in use. Without these resistors, the state of the data lines can not be guaranteed and performance may not be predictable. In this example, only two data lines are used, so the other two are tied directly to ground. With this circuit, pressing either of the buttons will cause the data line to go high and initiate a transmission. On the decoder side, a piezoelectric buzzer is attached directly to the D1 line. When the button connected to the D1 line on the encoder is pressed, the buzzer will sound. The D0 line is connected to a relay through a transistor buffer. The decoder can output 25mA, which is sufficient to drive small relays, but may not work for larger coils. The transistor is used to provide the higher current and voltage required to activate a larger relay. With this circuit, when the D0 line goes high, it will turn on the transistor, which will energize the relay and connect the terminals. Page 5 ENCODER VCC DECODER Start Up 200k To Transmitter VCC GND 1 VCC GND 8 2 DATA_OUT D0 7 3 D3 D1 6 4 SEL_BAUD D2 5 Sleep Mode GND GND RELAY OUT 200k GND Start Up 1 2 VCC VCC LICAL-ENC-LS001 GND Is the DATA_IN line high? GND VCC Sleep Mode NO 2N2222 VCC VCC GND GND 8 D0 7 VCC 3 D3 4 SEL_BAUD D1 6 D2 5 LICAL-DEC-LS001 RELAY-SPDT YES GND 2.2k 10k GND GND BUZZER Figure 4: LS Series Application Circuits Are any data lines high? Start Time-Out timer NO YES 131mS Time-Out? Get the data from the data lines ONLINE RESOURCES ® YES NO Encode for error correction Receive data www.linxtechnologies.com • • • • • Latest News Data Guides Application Notes Knowledgebase Software Updates Create the packet Send the packet NO If you have questions regarding any Linx product and have Internet access, make www.linxtechnologies.com your first stop. Our website is organized in an intuitive format to immediately give you the answers you need. Day or night, the Linx website gives you instant access to the latest information regarding the products and services of Linx. It’s all here: manual and software updates, application notes, a comprehensive knowledgebase, FCC information, and much more. Be sure to visit often! Is the data valid? YES Output the data on the data lines. Figure 5: LS Series Encoder Flowchart Page 6 Check data for errors Figure 6: LS Series Decoder Flowchart Page 7 WIRELESS MADE SIMPLE ® U.S. CORPORATE HEADQUARTERS LINX TECHNOLOGIES, INC. 159 ORT LANE MERLIN, OR 97532 PHONE: (541) 471-6256 FAX: (541) 471-6251 www.linxtechnologies.com Disclaimer Linx Technologies is continually striving to improve the quality and function of its products. For this reason, we reserve the right to make changes to our products without notice. The information contained in this Overview Guide is believed to be accurate as of the time of publication. Specifications are based on representative lot samples. Values may vary from lot-to-lot and are not guaranteed. "Typical" parameters can and do vary over lots and application. Linx Technologies makes no guarantee, warranty, or representation regarding the suitability of any product for use in any specific application. 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