# 7 Segment Circuit Design

#### halilozenc54

Joined May 17, 2021
4
Hello, This term I have a project which is i will design a 7 segment display circuit shows my name in 1s period. And if my name have a letter which is not
appropriate for 7 segment it will shown as 0. i,e my name will shown as HALIL O0E0C. I have designed my circuit with 4 flip flop and 1 555 ic timer. I have solved k-map for my name. It is working properly but there is a problem. Since i have 4 flip flop my circuit work as A-B-C-D, 4 variable design and there is 16 digits in it.
When i solved kmap for my name there was 11 digits including space between name and surname and i used x for last 5 digits for completing 16, in online k-map solver . As a result of this my display shows that HALIL OOENC then keep showin random things since it complete its to 16. And then resets back. Since, I am a new student i haven't understand how this ic's work. Please don't judge me.

#### MrChips

Joined Oct 2, 2009
23,536
Thread moved to Homework Help from Digital Design.

#### MrChips

Joined Oct 2, 2009
23,536
Why not display Z as 2 and N is upside down U?
Also why not show the remaining five states as spaces?

Show your work that you have done so far.

#### halilozenc54

Joined May 17, 2021
4
First, Z is shown as 0 by my Tutor, i must not use lower case, and i can fix them easily. Secondly, If i show them as spaces there will be 5 second gap. It must be one more space and start again from 'H' for 1 second period. Since i used proteus for simulate circuit i couldn't uploaded it.

#### dl324

Joined Mar 30, 2015
12,871
Since i used proteus for simulate circuit i couldn't uploaded it.
You can print to PDF to get a black and white schematic without the distracting grid that Proteus uses. Post a screen capture from the PDF or post the PDF file. Most would prefer an image.

#### MrChips

Joined Oct 2, 2009
23,536
Three horizontal lines could be used as Z.

Code:
For Z:
_____
_____
_____

For N:
____
|    |
|    |
We are not using lower case. All we have are seven segments to play with.
Ok, then leave one space before recycling.

We cannot help you without seeing a truth table and a circuit diagram.

#### RBR1317

Joined Nov 13, 2010
633

But it is not "random things"; it is exactly what you designed. If you want something else to be shown, then use what you want instead of "X" in the K-map.

#### halilozenc54

Joined May 17, 2021
4
I've attached file which includes table for 7 segment display and my circuit. I have solved K-map for 4 variable for a-b-c-d-e-f-g-l1-l2 parts seperately. I used 4 variable since my name have between 0-11 elements including spaces i used. In this table i used spaces as 0. Since my truth table is not true, i didn't upload it.Since , In 4 variable k-map solving there is 16 digits, I've used x , as a result of this my circuit randomly displaying letters after HALIL O0E0C part. It show that HALIL O0E0C 00]0 and resets.

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#### dl324

Joined Mar 30, 2015
12,871
as a result of this my circuit randomly displaying letters after HALIL O0E0C part.
You have the inverters labeled backwards:

Did you connect the gates correctly in spite of the labeling error?

Why are you using inverters when the flip flops have both polarity outputs?

#### halilozenc54

Joined May 17, 2021
4
Since I have lack of knowledge about digital and integrated circuits, I couldn't imagined how flip flops outputs work. Thanks for helping. And i connected gates correctly and i am sure i did,because i can see my name correctly but there is addition letters after that. I think my problem is about Booelan algebrea, there is missing digits. there must 16 digits for 4 variable k-map but i have only 11. Or i ca do space , H,A,L,I,L,space, O,O,E,0,C, space, and it is still have lack of 3 digits. I could'nt find how can i turn back to 0000 again for flip flops.
Thanks,
Halil.

#### dl324

Joined Mar 30, 2015
12,871
So the random display you were taking about is for the counts after 10? If that's the case, just reset the flip flops after the last letter in your name is displayed.

After you've received a grade for your work, come back to this thread and I'll show you how to draw your schematic more neatly. If I was your instructor, I'd give deductions for sloppy work.