Apparatus and method for timing an output of a remote keyless entry system

摘要

A crystal-less keyless entry system includes a microprocessor or micro controller, a timing circuit, and a radio frequency circuit. The timing circuit is a unitary part of the microprocessor. When configured to compensate for power up delays in the radio frequency circuit, the microprocessor outputs data having stretch times that compensate for power up delays in the radio frequency circuit. The stretch times do not substantially vary the substantially constant bit time periods of the output data. When configured to detect a switch activation, the microprocessor transmits a bit within a period that includes a debounce time interval. The method of transmitting data using a crystal-less remote keyless entry system includes selecting a bit from a data stream and encoding the bit with a Manchester like encoding process. The Manchester like encoding process debounces a switch between logic levels of the encoded data.