SOFTWARE DECODER ALGORITHM FOR INFRARED REMOTE (IR) CONTROL PROTOCOL
Publication Date: 2004-Nov-23
The IP.com Prior Art Database
In an embodiment, a software algorithm for an IR remote control protocol is provided. The output of an IR sensor is set compliment of the input. Hence when IR signal is not present, the output of the IR sensor is Logic High. Whenever the IR sensor receives the first start bit, the output goes low after half bit period. This transition triggers an Interrupt of a Micro controller. An interrupt routine samples the signal at the ¼ th of the bit period. The routine also initiates another timer interrupt that samples the signal on every subsequent half-bit period. Both the samples of every bit are checked whether they are complimentary to each other. Once all the bits are sampled, last 11 bits are decoded for one of 2048 possible keys and the function corresponding to that routine is executed.