The HSC500 is a code hopping decoder designed for secure Remote Keyless Entry (RKE) systems. The HCS500 utilizes the patented KEELOQ® code-hopping system and high security learning mechanisms to make this a canned solution when used with the HCS encoders to implement unidirectional remote and access control systems. The HCS500 can be used as a stand-alone decoder or in conjunction with a microcontroller through a serial interface. The manufacturer’s code, encoder keys, and synchronization information are stored in encrypted form in external EEPROM. The HCS500 operates over a wide voltage range of 3.0 volts to 5.5 volts. The decoder employs automatic bit-rate detection, which allows it to compensate for wide variations in transmitter data rate. Sophisticated error checking algorithms are built in to ensure only valid codes are accepted. Typical applications include automotive remote entry systems, automotive alarm systems, automotive immobilizers, gate and garage openers, electronic door locks, identity tokens and burglar alarms. HCS500 is available in 8-pin DIP/SOIC packages.