dtmfout problem

[lerameur]

Hi,
I am using 20Mz
I think the problem is more hardware than software..



code:/
'*************************
'* Alarm system dialer *
'*************************


'//////////////////////////////
'// Pic chip configuration //
'//////////////////////////////

INCLUDE "modedefs.bas" 'Includes supoprt for PicBasic language
@ DEVICE pic16F88,CCPMX_ON

' Setup Crystal oscillator Frequency to be used by PIC chip in MHz
DEFINE OSC 20 'use external 20mhz crystal

ANSEL = 1
CMCON = 7 ' Turn OFF the comparators so pins can be used as digital I/O-pins

'///////////////////////////////////////
'// Screen initialization //
'///////////////////////////////////////


DEFINE LCD_DREG PORTB ' Set LCD Data port
DEFINE LCD_DBIT 4 ' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_RSREG PORTA ' Set LCD Register Select port
DEFINE LCD_RSBIT 2 ' Set LCD Register Select bit
DEFINE LCD_EREG PORTA ' Set LCD Enable port
DEFINE LCD_EBIT 3 ' Set LCD Enable bit
DEFINE LCD_BITS 4 ' Set LCD bus size (4 or 8 bits)
DEFINE LCD_LINES 2 ' Set number of lines on LCD

DEFINE LCD_COMMANDUS 2500
DEFINE LCD_DATAUS 250
DEFINE CHAR_PACING 2000
pause 2000


'/////////////////////////
'// PIN configuration //
'/////////////////////////

TRISA = %00011000 ' Set PORTA to all input
TRISB = %11111111 ' Set PORTB to all output
PortA = 0


'///////////////////////////////////////////////
'// Variable Declaration and initialization //
'///////////////////////////////////////////////


counter var byte
i var byte
counter=0


'//////////////////////////
'// Program starts here //
'//////////////////////////

Main:
lcdout $FE,1, "Counter:",dec counter
Pause 500

if PortA.4=1 then
counter=counter +1 'Counter at 1 dials phone number
goto Dial
endif

if PortA.4=0 then
counter=0
goto Main
endif

'//////////////////////////
'// End of program here //
'//////////////////////////

Dial:
'Determine which number to dial and dials it

lcdout $FE,1, "Dial:",dec counter
Pause 500

if counter =1 then 'begin counter loop
if PortB.0 = 1 then GOSUB Dial1760 'cel
if PortB.1 = 1 then GOSUB Dial4392 'Ken
if PortB.2 = 1 then GOSUB Dial9130 'Donald
if PortB.3 = 1 then GOSUB Dial758 'Lyne
Else
counter =1
goto Main
endif 'end counter loop

Pause 1000 'pause for 1 seconds
if (counter > 1) or (counter =0) then counter =1

'Keep counter to 1 after dialing, otherwise the program will keep dialing the number
' Will only redial if counter goes back to 0, that is alarm siren off

goto Main



'*************** subroutine here ********************
Dial1760: 'cel
lcdout $FE,1, "dialing1760 ",dec counter
Pause 500
PortA.1 = 1
pause 3000
DTMFOUT PortA.0, [5,1,4,4,4,4,4,4,4,2]
pause 4000 'Pause 4 seconds
DTMFOUT PortA.0, 20000,0, [5]
pause 2000 'Pause 2 seconds
PortA.1 = 0
return

end

/end code

[lerameur]

I think I might got the probe switch to 10x instead of 1x.. that would explain the 40v. I will check it once I get home...
if so I guess I would have would have something like 3.7v output peaks on the pin.

[lerameur]

Ok , the scoipe was set at 100x. now I read 4v at the output, but still a lot of noise after the filter, and only dials 50% of the times

k

[skimask]

but still a lot of noise after the filter, and only dials 50% of the times
k

Well, the PBP manual does say that any 'sound' output from the PIC, being 1-bit analog, is going to be 'noisy', a lot of harmonic content. And I would think that even if it's filtered well, it would still have a load of 'noise' in it. A low-pass 'brick wall' filter, with a steep 'slope/cutoff', with the -3db point set just above your highest frequency might handle that.
I guess I'm not really sure. I haven't relied on the PIC to do much sound (other than moving MP3 data back and forth for a player).

[lerameur]

I was initially thinking of going with a specialized DTMF chip. They are hard to get around here

[skimask]

I was initially thinking of going with a specialized DTMF chip. They are hard to get around here

I wouldn't think you'd need a special chip...just maybe brush up on some filter design techniques. After all, what you're trying to do has been done probably hundreds of times before. No reason why you can't do the same thing...

And also...

Here == ???????????????

[Darrel Taylor]

I'm not sure what affect it will have on DTMFOUT, but you have ....

ANSEL = 1

Which puts PORTA.0 in Analog mode.
And that's the DTMF pin.

Might try ...

ANSEL = 0
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