Frequency display for adjusting Potentiometer

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Rockzinstruz

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Hi all..

I'm working in function generator designing,here i'm using 47k potentiometer for frequency fine adjustment and frequency range selection obtained by switching of capacitors.

How to make the display of frequency range and particular frequency value in LCD display?
(Here using ADC0809 and 8051 micro controller)

Thanks.
 
Last edited:
The most accurate would be to add a counter circuit to display the actual frequency being generated.

The range could be shown by a single LED for each range.

What is the ADC0809 used for?
 
My function generator output gives the HZ to 1Mhz frequencies by switching the different capacitors and fine adjustment can be obtained by varying potentiometer.Here I wants to display the frequency value in LCD display according to the potentiometer adjustment through 8051 microcontroller interfacing.LCD input is the digital value for that I'm using ADC 0809.


Thanks.
 
I don't understand what you are describing. Can you post a circuit or block diagram?
 
Rockinstruz wrote:
Here I wants to display the frequency value in LCD display according to the potentiometer adjustment through 8051 microcontroller interfacing.LCD input is the digital value for that I'm using ADC 0809.
Click to expand...

Crutschow wrote
I don't understand what you are describing.
Click to expand...


JimB thinks:
What Rockinstruz is trying to do is to provide a digital display of frequency based on the rotational position of the potentiometer which is controlling the frequency of his oscillator.

This of course is the wrong way to do it and is doomed to mediocrity and failure.

As has already been suggested, measure the output frequency of the oscillator, job done!

JimB
 
Hi .....

How to display the frequency of sine wave analog signal in LCD using 8051.
If anybody know the ideas regarding of this project.Plz help me.


Thanks.
 
Ok....Actually I did the project function generator using max 038.In this project,I made the wave generation circuit using max 038.It produces the frequency in the range of 25Hz to 2 MHz.For frequency range selection, I interfaced 8051 microcontroller with switching circuit and added one potentiometer for fine adjustment of the frequencies.
[frequency range selection obtained by,switches interfaced with microcontroller and fine adjustment obtained by 47Kohm potentiometer]


Here,I wants to display the corresponding selected frequency with fine adjustment ;that is I wants to display the actual frequency is coming out from max 038 while adjusting the potentiometer.I need help in this part.
If anybody know the exact idea for my problem.Please suggest your ideas.


Thanks.
 
Frequency counter work by simply counting the number of pulses within a known period of time. The period, or gate time, changes depending on the frequency. For your frequency range the gate times might be 0.1mS, 10mS and 1 Second. Of course, the gate times will depend also on what resolution you want to display.

Monitoring the SYNC pin from the MAX038 is probably the best. However, I find the description for that pin in the datasheet a little confusing.
 
I don't remember the 8051 that well but I believe the counter is not that good for counting.
The links above show how to do this with a PIC and maybe you can see how from that. The idea in one of the links shows adding a AND gate to the input of the counter. The gate allows a simple counter to act like a smarter counter.
 
COSC pin of max 038 (5th pin)corresponds to the frequency of the function generator.Varying capacitor across the 5th pin makes the frequencies of waves.Fine adjustment potentiometer is connected to the 1st pin(reference pin)and 10 th pin(IIN) of max 038.
 
Maxim no longer makes the MAX038. There are probably many around. I have one in a signal generator I built years ago.
 
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