In SX Microcontrollers, SX/B Compiler and SX-Key Tool, PJMonty wrote:

Jon,

The ISR you wrote for decoding SIRCS data looks solid and quite compact.  I wrote a SIRCS decoder as part of a much bigger project a year ago.  In my case, dues to the way the rest of the project worked, I created a software timer that ran at .1 ms.  This gave me a way to time incoming pulses with .1 ms resolution.  For what it's worth, here is the pertinent part of the comment block for my code:

[code]; To decode, watch the input bit and wait for it to go low.  It should be held low for 
; 2.4 ms followed by .6 ms of high.  After that, the data starts coming in.  The key to
; decoding the remaining bits is to time the length of the lows that happen.  Technically,
; if it's low for .6 ms, it's a zero, and if it's low for 1.2 ms, it's a one.  All of these
; timings are subject to jitter and inaccuracy caused by the time base used in the cheap 
; remotes.  Because of this, I use 1 ms as a cutoff.  Below it is a zero, above it is a one.
; This (should) give me better handling of off timed pulses.   
[/code]

I'm not sure if this will give you any new ideas, but you never know.  In re-reading my comments, I realize I should change my cutoff value from 1 ms to .9 ms to actually be in the middle of  .6 ms and 1.2 ms.

[list]Thanks,
PeterM

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