Help with designing a circuit (LED 7 segment display)

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AWelectrics04

Joined Mar 5, 2025
1
I am currently designing a circuit to read 0 3 1 4 7 6 5 2 0 on the seven segment display. I have got it reading 0 3 1 0 and repeating, I have hit a wall and need some ideas, any help would be appreciated, I believe I’m not too far
 

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MisterBill2

Joined Jan 23, 2018
27,370
REally, it can be done with an 8 bit PROM and a binary counter. Program the ROM with the bit patterns to produce the desired display, and increment the P ROM with a simple binary counter. At the next count beyond the last digit, the eighth bit resets the binary counter. That allows you to make the string of numbers as long as you choose, limited by the size of the PROM
I doubt very much that a simpler circuit can be devised, unless it includes an actual processor with internal memory.
 
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sghioto

Joined Dec 31, 2017
8,634
I am currently designing a circuit to read 0 3 1 4 7 6 5 2 0 on the seven segment display. I have got it reading 0 3 1 0 and repeating, I have hit a wall and need some ideas, any help would be appreciated, I believe I’m not too far
Does it have to be all cmos logic, can a micro be used?
 
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sghioto

Joined Dec 31, 2017
8,634
What about the 1hz driver pulsing a CD4017 with each output driving an input on a decimal to bcd converter in the required order?
Full schematic details available.
1741312845404.png
 
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JohnSan

Joined Sep 15, 2018
124
Another idea....

You could use a prom, or simply use diodes since it's a relatively simple requirement.
See the attached circuit diagram. Its not complete, but shows the idea.
A set of pull down resistors hold the inputs to the 4511 to zero if no diode is conducting.
Where the diodes are shown not connected, obviously could be completely left out.
They are included here to show the concept.

The CD4017 Q9 output could be connected to its reset input, if two consecutive '0's are not required.
 

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MisterBill2

Joined Jan 23, 2018
27,370
Indeed it can also be done by using a decimal counter and a binary to seven segment decoder. It will require a few or gates, or a decimal to seven segment decoder. But the prom scheme can go on for hundreds of digits and not require any other logic.
 
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