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using 8051 as pulse counter

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waqar

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hi hello,

1) I have a 8051 Controller , A pulse Dialing Telephone Set, a off-hook indicator Circuit using optical coupler 4N25 and a LED. using 12 Mhz crsytal.


2) I need to use 8051 as a pulse counter,


3) From the Off-hook indicator the wire which gives logical High
Signal when ever the telephone set goes off-hook is connected at
P1.0.
>
> 4) At Pin 2.0 a LED is connected.
>
> 5) Controller should keep on monitoring Pin1.0
>
> ORG 00H
> MONITORING:
> JNB,P1.0,$
>
> 6) When ever the telephone set goes off-hook a logical high
signal will come at Pin1.0 , the controller turn on the LED and come
back to P1.0 Port Monitoring.
>
> SETB P2.0
> JMP MONITORING
>
> 7) Now the problem starts.... now when when the telephone dial
digit "1" , pulses will come at Pin1.0, now the controller
should move to next instruction which can count pulses and display
the LED with the corresponding pulses ..
>
> e.g. if "1" is pressed LED should turn off and turn on
again,
> if "2" is pressed LED should turn off and On
two times...
>
> A pulse dialing telephone set sents 10 Pulses Per Second when a
"0" is pressed, it means if the user press "1"
then LED should Blink 10 Times in a second...
>
> Swear i have tried but i don't even able to develop a logic...
>
> May i have to input delay for each digit and when ever a Pulse
comes the controller should compare those pulse with the delay and
then if they matches perform the function..
>
> CJNE commands..
>
> Or the Controller should be able to count the pulses and then
generate same amount of pulses out.
>
> I need some example code at least for one digit pulse e.g. how
the controller will count or compare for digit "0".

or if i use the timer C/T option sending pulses at p3.2 pin then it can count the pulses but there are two telephone sets ,,is there any way i can make the timer count using two bits (pins) for two telephone sets..

Also can you tell me the frequency of Busy Tone and Ring Back Tone,,, i know the dial tone frequency which is 400Hz.

>
> Thankyou.
 
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