Hi Wagner,
My answer is irrelevant then. I thought you were
the one who initiated this thread, but now I see that it was Salam.
Rogier
----- Original Message -----From: Wagner LipnharskiSent: Sunday, January 04, 2004 5:42 AMSubject: Re: [AVR-Chat] DTMFHi Rogier, what you mean? I didn't get the meaning of your answer.
Perhaps you didn't get that I was not asking for any help, I was only saying
what I did in the past, and worked very well, as a matter of fact, still
working in hundreds of that device installed around... :)
Wagner.
Rogier Schouten wrote:
> I'm impressd... I'm afraid that I cannot help you any further than by
> mentioning the block memory read routines in the Atmel app notes.
> Good luck!
>
> Rogier
> ----- Original Message -----
> From: Wagner Lipnharski
> To: AVR-Chat@yahoogroups.com
> Sent: Saturday, January 03, 2004 5:45 PM
> Subject: Re: [AVR-Chat] DTMF
>
>
> Of course an external and dedicated chip is the best and easy
> option.
> By the way, generating DTMF is not as difficult as is decoding it,
> so it can
> be done by software. I did it many years ago using a bare 8051 and
> 3.57MHz
> clock, produced a mix of two several points sinewaves, mixing them
> by
> software and finaly pumping into a R-2R 8 bits ladder, ended up in
> a nice
> and clean waveform. It required tricky instruction count in the
> sine table
> reading, as well luck in a form that an easy market crystal
> frequency cut
> allow it. The frequency generation was just a matter of speed
> reading the
> 128 bytes sine table (180 degrees), more or less table address the
> routine
> skip over at reading - represented a different produced frequency.
> The
> experiment was nice since it ended up creating enough software
> tecnology to
> allow production of several sounds that were widely used at the next
> projects. There is nothing like a sine wave sound generation... :)
>
> wagner.
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