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Discussion Groups | 68HC12 | Help me regarding DTMF

Join our technical discussions about Freescale Microcontrollers: M68HC12. (Freescale Semiconductor is a Subsidiary of Motorola).

Help me regarding DTMF - Manjunath - Apr 25 0:26:00 2003

Hello,Is any one Working DTMF Generation / Reception through Microcontroller. If So, Please Help me regarding that. I tried a lot but no result.Please anyone Help me. With Regards,

Manjunatha T.R.

E-mail :
---------------------------------



______________________________
Stellaris® MCU Family: New Parts, New Package, New Price.


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Re: Help me regarding DTMF - Robert Smith - Apr 25 5:39:00 2003

There are various approaches depending on your choice of microcontroller and
other trade offs.

For a small project I would probably use and outboard IC such as the Mitel
MT8870. However Mitel's presence on the internet is not very strong and
almost gets lost in all the noise generated by Mitel communications
companies.

Try DigiKey, they have some DTMF chips in their catalogue.

Search the web for "+dtmf+receiver" and/or "+dtmf+generator"

Bob Smith

--- Avoid computer viruses, Practice safe hex ---

-- Specializing in small, cost effective
embedded control systems --

http://www.smithmachineworks.com/embedprod.html Robert L. (Bob) Smith
Smith Machine Works, Inc.
9900 Lumlay Road
Richmond, VA 23236 804/745-1065
----- Original Message -----
From: "Manjunath" <>
To: <>
Sent: Friday, April 25, 2003 1:26 AM
Subject: [68HC12] Help me regarding DTMF > Hello,Is any one Working DTMF Generation / Reception through
Microcontroller. If So, Please Help me regarding that. I tried a lot but no
result.Please anyone Help me. > With Regards,
>
> Manjunatha T.R.
>
> E-mail : >
> --------------------------------- >
>
> --------------------------------------------------------
> To unsubscribe from this group, send an email to: > To learn more about Motorola Microcontrollers, please visit
> http://www.motorola.com/mcu



(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )

RE: Help me regarding DTMF - Vien Nguyen - Apr 25 12:01:00 2003

Hi,
to interface a DTMF device to a MCU, the MCU should have a TPU module. For
your info, Motorola's 68K's CPU32 is a good one, or Hitachi's H8S/2xxx
series.

For transmission, you need to program the TPU channel as an TPU output pin
w/ appropriate period and frequency for a particular DTMF 'tone'. For
reception, you do the opposite of the above.

Of course, you could do it w/ an Input Capture pin for DTMF reception, and
reprogram that same IC pin to a normal ouput pin for transmission. This way
requires quite a bit more thinking and coding, though.

Good luck.

Vien Nguyen.
______________________________
Stellaris® MCU Family: New Parts, New Package, New Price.


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Re: RE: Help me regarding DTMF - Andrei Chichak - Apr 25 12:08:00 2003

At 10:01 AM 4/25/2003 -0700, you wrote:
>Hi,
>to interface a DTMF device to a MCU, the MCU should have a TPU module. For
>your info, Motorola's 68K's CPU32 is a good one, or Hitachi's H8S/2xxx
>series.
>
>For transmission, you need to program the TPU channel as an TPU output pin
>w/ appropriate period and frequency for a particular DTMF 'tone'. For
>reception, you do the opposite of the above.
>
>Vien Nguyen.

So, how would you generate the dual tones using the TPU? Would you write
some microcode to generate the two PWMs on one pin or diode OR two channels?

Andrei

______________________________
Stellaris® MCU Family: New Parts, New Package, New Price.


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Re: Help me regarding DTMF - Frank - Apr 26 6:33:00 2003


Hi,

National has a TP5088 DTMF generator, requires a crystal of 3.57945 Mhz
Teltone has a M-8870 DTMF receiver.

I used this as a remote intruder alarm back in good ol SA. The diamond
diggers used to work in the sticks and at night times had to leave their
unprocessed "hot" gravel with potential diamonds, overnight. During night
time, the local folks would come and steal the gravel!!! Not nice.

So I was contracted to design a infrared intruder alarm running of batteries
and when activated used DTMF codes over VHF to inform the owners with the
untruder cell number. Now that really brings back some memories!!!
----- Original Message -----
From: "Robert Smith" <>
To: <>
Sent: Friday, April 25, 2003 3:39 AM
Subject: Re: [68HC12] Help me regarding DTMF > There are various approaches depending on your choice of microcontroller
and
> other trade offs.
>
> For a small project I would probably use and outboard IC such as the Mitel
> MT8870. However Mitel's presence on the internet is not very strong and
> almost gets lost in all the noise generated by Mitel communications
> companies.
>
> Try DigiKey, they have some DTMF chips in their catalogue.
>
> Search the web for "+dtmf+receiver" and/or "+dtmf+generator"
>
> Bob Smith
>
> --- Avoid computer viruses, Practice safe hex ---
>
> -- Specializing in small, cost effective
> embedded control systems --
>
> http://www.smithmachineworks.com/embedprod.html > Robert L. (Bob) Smith
> Smith Machine Works, Inc.
> 9900 Lumlay Road
> Richmond, VA 23236 804/745-1065 >
> ----- Original Message -----
> From: "Manjunath" <>
> To: <>
> Sent: Friday, April 25, 2003 1:26 AM
> Subject: [68HC12] Help me regarding DTMF > > Hello,Is any one Working DTMF Generation / Reception through
> Microcontroller. If So, Please Help me regarding that. I tried a lot but
no
> result.Please anyone Help me.
> >
> >
> > With Regards,
> >
> > Manjunatha T.R.
> >
> > E-mail :
> >
> >
> >
> > ---------------------------------
> >
> >
> >
> >
> > --------------------------------------------------------
> > To unsubscribe from this group, send an email to:
> >
> >
> > To learn more about Motorola Microcontrollers, please visit
> > http://www.motorola.com/mcu
> >
> >
> >
> >
> >
> >
> --------------------------------------------------------
> To unsubscribe from this group, send an email to: > To learn more about Motorola Microcontrollers, please visit
> http://www.motorola.com/mcu





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Re: Help me regarding DTMF - David Lecomte - Apr 28 2:30:00 2003



Manjunath wrote:

> Hello,Is any one Working DTMF Generation / Reception through Microcontroller. If So, Please Help
me regarding that. I tried a lot but no result.Please anyone Help me. > With Regards,
>
> Manjunatha T.R. I'm not sure what you want to do?

There were several microprocessor compatible
DTMF generators and receivers available.

I dont know if Mitel are still in business but
they had a range of DTMF transceivers and
receivers and generators. The transceiver part
number was MT8889 from memory.

Do you want to just know how to interface
to them, or are you trying to generate
and detect the tones with software, or
a combination of software and hardware?

Generation isn't too hard without a generator,
depending upon the specifications you need to meet.
Detection is a bit trickier, but still possible
in software. A hardware approach, using a dedicated
transceiver is a hell of a lot easier! Yours Sincerely,

David leComte





(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )

Re: Help me regarding DTMF - Manjunath - May 1 3:12:00 2003

Hello David,Can U please share ur ideas on how to go about this.I will share about how I approached 1. initialisation2. check line is it ringing and on hook3 dial When I make off_hook the line is getting dropped to -10volts, still i can't able to get any communication from exchange.Please Guide me

David Lecomte <> wrote:

Manjunath wrote:

> Hello,Is any one Working DTMF Generation / Reception through Microcontroller. If So, Please Help
me regarding that. I tried a lot but no result.Please anyone Help me. > With Regards,
>
> Manjunatha T.R. I'm not sure what you want to do?

There were several microprocessor compatible
DTMF generators and receivers available.

I dont know if Mitel are still in business but
they had a range of DTMF transceivers and
receivers and generators. The transceiver part
number was MT8889 from memory.

Do you want to just know how to interface
to them, or are you trying to generate
and detect the tones with software, or
a combination of software and hardware?

Generation isn't too hard without a generator,
depending upon the specifications you need to meet.
Detection is a bit trickier, but still possible
in software. A hardware approach, using a dedicated
transceiver is a hell of a lot easier! Yours Sincerely,

David leComte
Yahoo! Groups Sponsor
--------------------------------------------------------
To unsubscribe from this group, send an email to: To learn more about Motorola Microcontrollers, please visit
http://www.motorola.com/mcu Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
With Regards,

Manjunatha T.R.

E-mail : ---------------------------------




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