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f1fco

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Joined: 18/03/2012
Location: France
Posts: 155

Posted: 11:58am 08 Jul 2014

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hello to all,
is it possible to generate DTMF tones with a Maximite ?
command DTMFOUT exist in others BASICs (by exemple in PIC PASIC PRO)

an idea :
by exemple DTMF "0" is 941 Hz + 1336 Hz
use the command TONE 941,1336,1000 : 941Hz, 1336Hz during 1000ms
with a mixer beetwen left and right channel

is it OK ?
I try it tomorrow

73s from F1FCO, Pierre, south of France

73s de F1FCO

halldave

Senior Member

Joined: 04/05/2014
Location: Australia
Posts: 121

Posted: 12:47pm 08 Jul 2014

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I know there is an I2C compatible DTMF / Tone Generator chip you could use

PCD3311 or PCD3312 have not tried it though

David

Lou

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Joined: 01/02/2014
Location: United States
Posts: 229

Posted: 01:15pm 08 Jul 2014

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f1fco,

I said on another post yesterday that I was going to try to dial touch tones when I got a round tuit. I don't have my tuit yet so I'll be watching here for someone who has tried it.

I have not seen a DTMFOUT or TONE command but maybe Geoff could add in the future if there was interest (I am interested), although touch tones could easily be generated manually in code using the two PWM's and some timing routines.

73, call sign here is AA9RT

Lou

Microcontrollers - the other white meat

TassyJim

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Joined: 07/08/2011
Location: Australia
Posts: 6220

Posted: 01:48pm 08 Jul 2014

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I would also look at the MT8880 chip if the PWM/TONE outputs are not successful.
The frequencies do need to be close so I think using higher frequencies from the maximite then using a couple of 4040 or similar divider chips to bring the frequencies back down.

All the external components will make the MT8880 look easy although you do need a crystal.

Hopefully, the simple TONE commands works without any extras.

Jim

Edited by TassyJim 2014-07-09

VK7JH
MMedit

f1fco

Senior Member

Joined: 18/03/2012
Location: France
Posts: 155

Posted: 02:51am 09 Jul 2014

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it works fine !!!
just a pot of 10Kohms beetwen left and right audio to mix signals

TONE 697,1209 send DTMF "1"
TONE 697,1336 send DTMF "2"
TONE 697,1477 send DTMF "3"
...

that all folks

F1FCO, Pierre

73s de F1FCO

Lou

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Joined: 01/02/2014
Location: United States
Posts: 229

Posted: 04:55am 09 Jul 2014

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Thanks Pierre,

Good to know it works. I run multiple 2 meter and 440 repeater systems and a programmable touch tone dialer will help get me through the authorization codes to get into the remote programming functions, like daylight savings time changes, etc. Should be easy with the uMite.

Lou

Microcontrollers - the other white meat

f1fco

Senior Member

Joined: 18/03/2012
Location: France
Posts: 155

Posted: 05:06am 09 Jul 2014

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hi Lou,
I use also PIC BASIC PRO compiler (v 3.0) with PICs (16F... or 18F...)
it is also easy to generate DTMF (fonction DTMFOUT) with a keypad 4 x 4
or specialised chips like 5089

I have buy last week a TFT Maximite and I want to write a DTMF dialer with it
16 virtuals button on the screen, a mixer (pot 10K) and a little attenuator for micro input of the transceiver and a digital output (via a transistor) to PTT

73s from F1FCO, Pierre

73s de F1FCO

hitsware
Guru

Joined: 23/11/2012
Location: United States
Posts: 535

Posted: 06:23am 09 Jul 2014

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> Should be easy with the uMite.

uMite as opposed to MaxiMite doesn't have TONE function
( which produces sine-waves )
If squarewaves will work ( ????? ) then PWM might do the trick .

Lou

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Joined: 01/02/2014
Location: United States
Posts: 229

Posted: 08:17am 09 Jul 2014

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Pierre,
Are you using student, silver, or gold version of PIC Basic Pro ??
I have looked at PBP3 in the past, I like it but have not tried it.
Have you looked at or used Great Cow Basic ?? If so what do you think and how does it stack up with PBP3 ??
I have used and liked PIC 12F's and 16F's in the past writing assembler, but machine code on the PIC's is a real pain in the - you know what -.

Yes, filter and transistor or LM386 amplifier on square waves should do the trick for DTMF.

hitsware,
I want to stick with smaller microcontrollers than MaxiMite to do tasks such as DTMF.
I have made on hand built proto board a frequency generator circuit using uMite 44 pin, PWM, IR remote control for keypad, and 2x16 line LCD to trip through menu's for a project I'm working on. This project has resulted in the coming LCDuMite boards Zonker is finishing up now. The LCDuMite board will be perfect for the DTMF we have been talking about, and many other small hand-held projects I have in mind.

Lou

Microcontrollers - the other white meat

f1fco

Senior Member

Joined: 18/03/2012
Location: France
Posts: 155

Posted: 12:13pm 10 Jul 2014

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hi Lou,
difficult for me (I am French) to write, to read and to understand all the messages in english
I have a gold version of PBP 3
I dont know Great Cow Basic
I search on google : its free and graphical

for square waves on �Mite, R/C filters do the job
with PICBASIC PRO, the command DTMFOUT produce squares waves
just 2 R (1Ko) and 2 caps (0.1�F) and direct in my VHF radio

for decoding DTMF, the (only) solution is to use a MT-8870 (DTMF decoder)
and read the 5 pins (DTMF presence and 4 datas)

its past midnight, I go to bed
Pierre

73s de F1FCO

Keith W.
Senior Member

Joined: 09/10/2011
Location: Australia
Posts: 118

Posted: 04:45pm 10 Jul 2014

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Here are some components from Rockby Electronics in Melbourne which are interesting, especially for the price.

First is PCD3312CT which is a versatile Philips I2C driven DTMF/Modem/Musical tone generator, stock number 3697 at just over 50c each. These are surface mount but 8 pin and not too small. These chips will also generate modem tones but I did not find cheap modem receivers (or complete modems) at near the above prices.

The next item found is 75T204-IP5V Low Power DTMF Receivers which cost $3 total for a packet of 58, or 2 tubes. Stock number 40884 and 14 pin DIL.

Both the above devices require (or can share) a 3.579545 MHz crystal, a very common frequency as for NTSC television colour sub carrier. Stock number 33768 for HC49/U style with other packages available and again about 50c each. I have purchased some of the above but not tried yet, and yes I have 58 Receivers. The 14 pin dip is easily tried but I will need the surface mount generator working first.

DTMF dual tones may be generated using the Micromite PWM outputs as F1fco has demonstrated above. The distortion specification for the tones is not onerous with distortion to be at least 20 dB below the lower tone. However without filtering the square wave output will exceed this, likely limiting reliable performance. Below is a filter circuit, borrowed from a Texas Instruments application note, where square waves from two processor outputs are combined to give the sum of the two frequencies. This filtering is performed within most DMTF generator chips.

Keith W.

Lou

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Joined: 01/02/2014
Location: United States
Posts: 229

Posted: 10:10am 11 Jul 2014

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Pierre,

Thanks, your english is very good I understand all you're saying.

On your first post you said DTMF tones for Maximite, my pea-sized brain translated that to uMite and the projects I'm working on, so my first replies may sound like babble in relation to Maximite uMite. But I'm on track now and still working on uMite.

You wrote:

for square waves on �Mite, R/C filters do the job
with PICBASIC PRO, the command DTMFOUT produce squares waves
just 2 R (1Ko) and 2 caps (0.1�F) and direct in my VHF radio

Are you feeding the filtered DTMF tones to your VHF (2 meter?) radio to control your repeater? That's what I had in mind to pre-program some of the long sequences for repeater control.

Also thinking of using uMite for a minimal repeater controller, would definately need a DTMF reciever like the MT-8870 (or MT-8880 as Jim said) and a programmable voice chip.

Any ideas on a good voice chip the uMite could use for such an application ??

Lou

Microcontrollers - the other white meat

f1fco

Senior Member

Joined: 18/03/2012
Location: France
Posts: 155

Posted: 04:57am 12 Jul 2014

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for Lou...
DTMF out of a �Mite (or any PIC) with R/C filter, a pot (10K) to adjust level to input of your transmitter

I practice ATV since 20 years ago...
I build with my friend F5AD some ATV repeaters with DTMF commands
I use MT8870, with 5 outputs : 4 datas and 1 DTMF presence
you peer the pin DTMF presence (or by interrupt) and you read the 4 datas
you have the received DTMF code

I can send you by direct email the code source in PICBASIC PRO to do this (comments are in French !!!)
I have also a little programm in MMBasic to do that
I can post here

F1FCO, Pierre

73s de F1FCO

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