microchip Hcs301 free download

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HCS301 KEELOQ® Code Hopping Encoder FEATURES Security · · · · · · Programmable 28-bit serial number Programmable 64-bit encryption key Each transmission is unique 66-bit transmission code length 32-bit hopping code 34-bit fixed code (28-bit serial number, 4-bit button code, 2-bit status) · Encryption keys are read protected DESCRIPTION The HCS301 from Microchip Technology Inc., is a code hopping encoder designed for secure Remote Keyless Entry (RKE) systems. The HCS301 utilizes the KEELOQ® code hopping technology, which incorporates high security, a small package outline and low cost, to make this device a perfect solution for unidirectional remote keyless entry systems and access control systems. PACKAGE TYPES PDIP, SOIC S0 S1 S2 S3 1 8 VDD Operating · · · · · · · · · 3.5--13.0V operation Four button inputs No additional circuitry required 15 functions available Selectable baud rate Automatic code word completion Battery low signal transmitted to receiver Battery low indication on LED Non-volatile synchronization data HCS301 2 3 4 7 6 5 LED PWM VSS HCS301 BLOCK DIAGRAM Oscillator Reset circuit LED LED driver Controller Power latching and switching Other · · · · · · · Functionally identical to HCS300 Easy to use programming interface On-chip EEPROM On-chip oscillator and timing components Button inputs have internal pulldown resistors Current limiting on LED output Low external component cost EEPROM Encoder PWM 32-bit shift register Typical Applications The HCS301 is ideal for Remote Keyless Entry (RKE) applications. These applications include: · · · · · · Automotive RKE systems Automotive alarm systems Automotive immobilizers Gate and garage door openers Identity tokens Burglar alarm systems VSS VDD Button input port S3 S2 S1 S0 2000 Microchip Technology Inc. Preliminary DS21143A-page 1 HCS301 The HCS301 operates over a wide voltage range of 3.5V to 13.0V and has four button inputs in an 8-pin configuration. This allows the system designer the freedom to utilize up to 15 functions. The only components required for device operation are the buttons and RF circuitry, allowing a very low system cost. 1.1.2 SECURE LEARN* The transmitter is activated through a special button combination to transmit a stored 48-bit value (random seed) that can be used for key generation or be part of the key. Transmission of the random seed can be disabled after learning is completed. Most keyless entry systems transmit the same code from a transmitter every time a button is pushed. The relative number of code combinations for a low end system is also a relatively small number. These shortcomings provide the means for a sophisticated thief to create a device that `grabs' a transmission and re-transmits it later or a device that scans all possible combinations until the correct one is found. The HCS301 employs the KEELOQ code hopping encryption algorithm to achieve a high level of security. Code hopping is a method by which the code transmitted