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Thread

DTMF

DTMF

2004-01-02 by Salam

How can an AVR encode and decode DTMF tones  ??

Re: [AVR-Chat] DTMF

2004-01-02 by Rogier Schouten

Hi,
Take a chip for that purpose. I believe MITEL makes them. MT8870D is a DTMF decoder, and they have encoders as well.
Rogier
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----- Original Message -----
From: Salam
Sent: Friday, January 02, 2004 1:00 PM
Subject: [AVR-Chat] DTMF

How can an AVR encode and decode DTMF tones ??



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Re: [AVR-Chat] DTMF

2004-01-03 by Reza

maybe mitel 8880 IC will be usefull.


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Re: [AVR-Chat] DTMF

2004-01-03 by Wagner Lipnharski

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.
Show quoted textHide quoted text
----- Original Message -----
From: "Rogier Schouten" <r.a.schouten@student.tue.nl>
To: <AVR-Chat@yahoogroups.com>
Sent: Friday, January 02, 2004 9:40 AM
Subject: Re: [AVR-Chat] DTMF


Hi,

Take a chip for that purpose. I believe MITEL makes them. MT8870D is a DTMF
decoder, and they have encoders as well.

Rogier

Re: [AVR-Chat] DTMF

2004-01-03 by Rogier Schouten

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 -----
Show quoted textHide quoted text
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.


----- Original Message -----
From: "Rogier Schouten"
To:
Sent: Friday, January 02, 2004 9:40 AM
Subject: Re: [AVR-Chat] DTMF


Hi,

Take a chip for that purpose. I believe MITEL makes them. MT8870D is a DTMF
decoder, and they have encoders as well.

Rogier






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Re: [AVR-Chat] DTMF

2004-01-04 by Wagner Lipnharski

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:
Show quoted textHide quoted text
> 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.

Re: [AVR-Chat] DTMF

2004-01-04 by Rogier Schouten

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
Show quoted textHide quoted text
----- Original Message -----
Sent: Sunday, January 04, 2004 5:42 AM
Subject: Re: [AVR-Chat] DTMF

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.




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Re: [AVR-Chat] DTMF

2004-01-12 by Les Grant

Hi Salam,

On 2 Jan 2004 at 12:00, Salam wrote:

> How can an AVR encode and decode DTMF tones  ??

You can encode DTMF in hardware or software. See Atmel application 
note 314 a software method. There are several chips you can use to 
decode DTMF including the MT3270 family from Zarlink (used to be 
Mitel).

Regards,
Les.


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