DTMF receiver

[mister_e]

You replace BANK0, BANK1 etc bank calls with CHK?RP, you deleted their BANK macro.

Al variable are define in the regular way
COUNT VAR BYTE *** carefull it's a reserver word
RESULT VAR BYTE

DE is replace with DATA

forget all ORG

and when you use those variable in asm, you insert an underscore before.

They use interrupt.. look at the end of the PBP manual or use Darrel interrupt in ASM, AND forget the context save/restore section.

list is still long enough... i would probably suggest you to compile their code, see if it works, if so, add your own stuff in.

I can't remember to have messed with DTMF decoding 'till now.

Did you found a MT8870 somewhere?

[Darrel Taylor]

I remember helping Josuetas on a project like that.

But I can't seem to remember any words we used that would produce a search result.

As I recall he was implementing one of the Microchip Application Notes (AN???)
More searching is in order.
<br>

[mister_e]

AN257...
DTMF Detection Using PIC18 Microcontrollers
http://www.microchip.com/stellent/id...pnote=en024294

Which use some kind of FFT.

[mackrackit]

Found this. Looks scary!
http://www.geocities.com/constantine...ntent/dtmf.htm

[skimask]

I've got that FFT firmware from Alciom running on an 18F4620, hooked up thru PBP. Works like a champ on music, and does very well with DTMF, as long as you've got a solid low-pass filter in front of the A/D input. I don't have a video with the DTMF example on the site and the firmware isn't set up specifically for DTMF in the video that is posted.
http://web.ndak.net/jdgrotte/picalyzer/picalyzer.htm
However, when I did try it with DTMF, I slowed the sample rate down from 19Khz to 9.5Khz, and I was able to easily pick out each frequency in the output on the LCD.
The deal is, the firmware needs to be bought thru Alciom. I've got an NDA with Alciom on the firmware specifically for the purpose of interfacing it with PBP (which wasn't really that hard, but needed a few tweaks here and there).
But if a guy is going to build a number of articles, it might be the way to go. From what I've read, those 2 Microchip app notes about FFT and the DTMF are fairly good at explaining the theory, but fall WAY short on actually working properly.

[mister_e]

Dave, it's exactly the same link as in post 3

[mackrackit]

Dave, it's exactly the same link as in post 3

Now that is embasssing. Being I looked around for 15 minutes to find that.

[lerameur]

Hey Mister e, I did try to look for MT8870 and other chip and about 6 other chip with entirely different code, HT9170 ....

I will have to seriously read these paper carefully, so I guess the conclusion there is still no way to easily read DTMF.

k

[skimask]

I remember helping Josuetas on a project like that.
But I can't seem to remember any words we used that would produce a search result.
As I recall he was implementing one of the Microchip Application Notes (AN???)
More searching is in order.
<br>

Ran across this...might be what you were looking for...
http://www.picbasic.co.uk/forum/showthread.php?t=6867