AVR-Chat

Most consumer electronics IR remotes use a protocol called RC5. Google
that. It's not compatible with a UART.

On AVRfreaks.net, I contributed an AVR implementation and PC side
software to make a learning IR remote. Look in the projects section
for "TWIRP". Also, there are quite a few other RC5 projects. You can
also purchase "IRman" and similar devices that receive RC5 and produce
a UART serial corresponding code set of digits. That's what the
receive side of TWIRP does, along with a 'scope-like display on a PC.
The sending side of TWIRP allows a PC (or microprocessor) to replay
learned codes. 



--- In AVR-Chat@yahoogroups.com, xolang1 <xolang1@...> wrote:
>
> 
> Hi Everyone
> &nbsp;
> Im trying to determine the protocol behind an unknown serial data
stream coming from an infrared receiver module with data coming from
an IR remote control.
> &nbsp;
> Since I dont have a scope, I tried to hook this signal to a maxim
level converter so that it could be viewed on a PC terminal. I tried
changing the terminal properties(baud,parity,databits,stopbits) to
find a possible sense out of the data stream but no luck so far.
> &nbsp;
> 1) I was hoping someone here could recommend a terminal program like
hypertrm that has some sort of protocol detection or at least autobaud
detection. Or something with its properties easily changeable during
runtime.
> &nbsp;
> 2) Anyone can make out anything out of the following facts? 
> &nbsp;
> With crude techniques, i found that with each key press on the
remote control, the -line goes:
> - LOW for about 8.5 msec (could be the start bit/char)
> - HI for about 4.5 msec
> - TOGGLES hi and low for about 52msec (could be the data)
> - HI for about 39.5msec&nbsp; (could be the stop bit/char)
> &nbsp;
> The remote control has 41 unique keys of which im guessing the data
bits are at least 6bits (64 combinations).
> &nbsp;
> The unit under study is a LED matrix message board with IR remote
control as input.
> &nbsp;
> 3) Any software that can work as a "PC oscilloscope"? As the data
may not even be in ASCII and could have its own character set. So its
best to analyze the exact wave form. Buying the scope is not an option
for now..too expensive and too bulky.
> &nbsp;
> &nbsp;
> Any helpwill be appreciated.
> &nbsp;
> thanks again!
> &nbsp;
> - Chris
> &nbsp;
> &nbsp;
> 
> 
>       
> 
> [Non-text portions of this message have been removed]
>