AVR-Chat

Hi 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.