DTMF Decoder Password

Filipe

Hello all members of this Forum;

My name is Filipe and i am New in programming MCU and new in this forum !!!

I nee know if any one make teste with the code DTMF Receiver for SX28 in down load section of Parallax?

I need any help for make this code:

The sx28 receive the Sound of DTMF for A/D pin or receive the ( 4 bits from MT8870 DTMF decoder ) is more dificulte with out MT8870 but less expensive to build !!!


Ok the project is:

send for ex. 12345# or 12345* DTMF code

12345# put HIGH some PIn of the SX28 ( ex. pin 4 )
12345* put Low the same pin of SX28 ( pin 4 )

The caracter # and * are the enter key

If I sent wrong code, the SX28 put HIGH other Pin ( ex. Pin 5 ) and check one more time DTMF code and if the codes are again wrong put High other Pin ( ex. pin 6 )

I dont know is the original code SX28 receiver and decoder DTMF code with out any other IC DTMF decoder of Chris are OK !!!


Regards for all;

Filipe

Jon Williams

If you're looking for a simple way to do this project, then I'd suggest you stick with an external decorder and let the SX28 handle the logic of the values coming in. If I were doing this, that's how I'd proceed (but then, I'm a big SX/B fan and not so good with assembly that will likely be required if you want to use the SX28 to decode the DTMF signal).

The strategy I'd use is to create a "background" process that monitors the output of the MT8870 for a new character and then moves it into a circular buffer. The foreground program, then, would simply focus on pulling characters from the buffer and processing them accordingly.

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Jon Williams
Applications Engineer, Parallax

Stephen

Hi Filipe,

The original authors of this code have moved on to other things a long time ago, so it's unlikely you'll find any support for it. You'll have to either work from the code and documentation that still exists or use an external DTMF decoder like Jon suggests...

If you're really set on getting the software version going (it's a much more elegant solution!), I've attached the app note and code that Ubicom/Scenix once distributed.

Cheers,
Stephen

pjv

Hey Stephen;

Good to see you're still around and monitoring the SX activities!

Peter (pjv)

Stephen

Thanks PJV! I don't get around as much as I should though...