Up/Down Counter using CD4510

[fenikssyach]

Hey All,,

Need a help from the expert of you. I have a project to build an up/down counter with ic 555 timer and using any ic for the counter. I choose CD4510, because it is presetable up/down counter. The task is to build a counter, when the input voltage is greater than 3V, it will count up 0-15. Otherwise, less than 3V it will count down, 15-0. For counting up from 0-15, it is successfull run. However, it gets stuck when I tried to count down from 15-10. I have preset the input number of two counter as 0001 (1) and 0101 (5) as well have set the PRESET ENABLE to HIGH, but it didnt count down. I need help from someone to correct my project.

I attached the picture of my circuit design. Please anyone help me to figure it out the problem. Thank you in advance..

 

[alec_t]

I have preset the input number of two counter as 0001 (1) and 0101 (5)

Your drawing seems to show the preset numbers being the same on both counters?
Shouldn't there be a pull-down resistor on the reset inputs of the counters?
Shouldn't the PE pins be taken low once the count has been preset?
Why is the CO pin of the lower 4510 grounded?

 

[fenikssyach]

Sorry for the wrong attachment,, it was when I tried to set both counters with input of 0011 (3), but still cant count down and count up also. A pull-down resistor? Sorry, but I dont know exactly the symbol of pull-down resistor in Multisim.

 

[alec_t]

The symbol is that of an ordinary resistor. The resistor should connect the pin to ground.

 

[fenikssyach]

Hei Alec_t. Thank you for your suggestion. It works now.

Another problem is to select the input voltage for driving the counter. If the input voltage is greater than 3V, it counts up 0-15. Otherwise, it counts down 15-0. My idea is using the tri-state buffer to select the input voltage. Am I correct? or any better idea for this matter.

Thank you.

 

[circuitspecialists]

If I understad your requirement correctly, a simple comparator circuit (op-amp) could be used with 3 volts as the trip point. Simply connect the output from the comparator to drive the up/down pin on your counters.
You may need to invert the output from the comparator but this could be easily done using the remaining op-amp in a dual single supply op-amp.

 

[alec_t]

Is the 3V level critical? If not, almost any Schmitt input gate would perhaps do. For example a CD4093 or CD40106 gate with a Vdd of 5V will change output state when its input goes above ~3V and below ~2V.

 

[Roff]

If I understad your requirement correctly, a simple comparator circuit (op-amp) could be used with 3 volts as the trip point. Simply connect the output from the comparator to drive the up/down pin on your counters.
You may need to invert the output from the comparator but this could be easily done using the remaining op-amp in a dual single supply op-amp.

It is simple to apply the control signal and the 3V threshold to the proper input pins to get the desired output polarity.

 

[fenikssyach]

Hey Alec_t, circuitspecialists, Roff.

Thanks for your suggestion. I have chosen the op-amp to select the input voltage as well I change my counters to CD4029 and it works properly. Btw, I have another question, is it possible that IC Counter 4029, can be reset to any binary number? In my case, I would like countdown from 15-0 and when it reaches 0, it should RESET to 15 as well whenever I press the RESET button, it should reset to 15 to restart the countdown. Is it possible that I can reset CD4029?

Thank you

 

[alec_t]

Is it possible that I can reset CD4029?

Yes. Arrange for the button to take the PE pin high briefly. Don't forget the pull-down resistor on the PE pin

 

[fenikssyach]

Thank you alec_t.. Now my counter is working properly. It can now count either up or down. I am using the 5kOhm variable resistor to set the input voltage. Then, the output from it goes to the op-amp to select the voltage. Whenever the input voltage is greater than 3V, it counts up. Otherwise it counts down. I do also put some logic gates from the output of the counters to do the RESET function. Since there are two counters (up and down), I do put also the logic gates by comparing with the output of op-amp to set the RESET function. Finally it works. Thank for all your inputs. really appreciated.