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pic 16f84 based dtmf controller

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Friend thanks to your reply ..... Yes I have to set the Configuration perfectly how he has say in asm
__FUSES _CP_OFF & _XT_OSC & _WDT_OFF & _PWRTE_ON
 

If the PIC is programmed correctly and the signals reaching it from the DTMF decoder are good, I'm afraid the only diagnosis I can give is the PIC is faulty.

Brian.
 

I´m not sure if this could be a candidate for root of the problem, but I would not feel comfortable sharing the same crystal between 2 oscillators as done in the circuit at link above.
 

Friend I have to connect as you say MT8870- PIN 8 TO PIC16F- PIN 15 But not work Friend I don't know about Program side Problems Actually their is given two HEX & One ASM & One PDF ( foxrc-1234.asm, foxrc-1234.HEX, rpc2a-nopw.HEX, rpc2a-no-pw.pdf ) I am using rpc2a-nopw.HEX Configuration - _CP_OFF & _XT_OSC & _WDT_OFF & _PWRTE_ON I am right are not
 
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That configuration word should work. Are you sure you are really setting the PIc up that way with your programmer? Try reading the PIC back and checking the config word really is set as you think it is.

As for sharing the clock signal, the MT8870 has quite a 'strong' clock output, provided the wiring to the PIC clock input is sensible it should work.

Brian.
 

Friend I have to check the pic Configuration after completing the program dump My programmer is TOP2009 universal Programmer I am sending the programmer result It's showing like this Please check this
top2009 ver5.02
Connectting OK
OK
OK,Data ´æ·ÅÔÚÎļþ»º³åÇø4200h¿ªÊ¼
Config = 7ff1
Read...Complete
Verify...Complete
 

That is the correct config word value for XT oscillator, power up timer enabled , watchdog disabled and no code protection.

The clock input on the 16F84 is pin 16 but you should get a duplicate but inverted copy of it leaving on pin 15. Connecting the MT8870 to pin 15 will not work.

Does the LED at the collector of Q1 light up when a DTMF tone is fed to the board?

Brian.
 

Friend I have to change pic pin 15 to 16 checked all connections perfectly as shown in the diagram every thing connections are perfect but not decoding the pic Q1 collector led will glowing when DTMF tone was applying and decoding the MT8870 I have to checked Out put status through 4 LED'S it's ok But problem is pic I didn't understand whats happening in side of PIC Friend Please excuse me my poor English
 

If the supply voltage is correct, it has a clock signal, it is programmed correctly and the reset line is high (it is connected directly to VDD in the schematic) it should work.

Is it possible for you to remove the ULN2803 and measure the voltages at the PIC PORTB with a voltmeter?

Perhaps you could post a photograph of the construction in case it gives any clues.

Brian.
 

I recently tried this NOPW Hex and it is working well.
Friends... anybody is having same kind of schematic and Codes for PIC16F628A instead of PIC16F84A.
TSat
 

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