7 segment decoder (Proteus 8)

Thread Starter

Black Widow

Joined Jan 15, 2018
13
Hello!

I have been working on a school project for quite a while, but I can't get this thingy to work properly in the simulator. The Binary to BCD converter that I have designed is working perfectly well (I have tested it with the 7447 decoder), but the decoder that I made isn't really. The 7 segment is displaying the diodes pretty much randomly, so I guess I made some error during the minimizing process with the karnaugh table, but I wen't through it a thousand times, still can't figure out what the problem could be. I have exported the whole thing into a PDF file so you guys can check it out if you wan't to. I would be really grateful for any suggestion.

Link:
https://drive.google.com/open?id=1Q7ftugNEM4C16eltB--AnEHIOw6n-A9s
 

Ian Rogers

Joined Dec 12, 2012
1,136
WOW! That's a lot of work for someone to go through... You would be better off zipping the protues project to save someone typing it all in..

I did this with a couple of Eproms... But yours is a whole lot of gates.... Are you going to build this, or are you stopping at simulation?
 

ArakelTheDragon

Joined Nov 18, 2016
1,362
They are sub circuits.. Each sub circuit has tons of gates in...
What's the point of "bin to BCD" and then a second decoder which is again bin to BCD? Meaning mod 1 and the decoder do the same.

The whole point is that you input a binary code to the decoder and it transforms it to BCD (7 segment plus dot point).
 

dl324

Joined Mar 30, 2015
16,846
I have exported the whole thing into a PDF file so you guys can check it out if you wan't to.
The moderators prefer for you to host files on this website so links don't become broken in the future.

It would be helpful if you had some text in the file describing what you're giving us. Pages 6-12 are the same logic. Pages 3 and 4 seem duplicated for no reason.
The 7 segment is displaying the diodes pretty much randomly, so I guess I made some error during the minimizing process with the karnaugh table, but I wen't through it a thousand times, still can't figure out what the problem could be.
It would be helpful if you posted how it isn't working so we don't have to wade through your schematics looking for problems.

EDIT: Also post your truth table, Kmaps, and boolean equations.
 

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dl324

Joined Mar 30, 2015
16,846
WOW! That's a lot of work for someone to go through... You would be better off zipping the protues project to save someone typing it all in..
That doesn't help if you don't use Proteus...
I did this with a couple of Eproms... But yours is a whole lot of gates.... Are you going to build this, or are you stopping at simulation?
This is homework, so the point of the problem is to have students solve it using logic vs a look up table.

A number of students have come here with the same problem. This is the first who seems to have solved the hard part.
 

Ian Rogers

Joined Dec 12, 2012
1,136
That doesn't help if you don't use Proteus...
It does if I want to help...
This is homework, so the point of the problem is to have students solve it using logic vs a look up table.

A number of students have come here with the same problem. This is the first who seems to have solved the hard part.
Agreed, that's why I want to help, my throwing in " I used an Eprom" wasn't a jibe, but a statement.. I know how much trouble and hard work the TS has put in!!!
 

Ian Rogers

Joined Dec 12, 2012
1,136
Okay I have tried a couple of you sub circuits.. I think you need to rename the input's and output's When QA is on I think Proteus is changing ALL the BCD to 7 seg encoders... I would use segA_QA and segB_QA etc... Also with S1 ~ S4 node1_s1.. etc..
 

Thread Starter

Black Widow

Joined Jan 15, 2018
13
Sorry for the deficient description of the project. The task is to design two circuits. 8 BIT binary to BCD circuit, and a 7 segment decoder. The 8 BIT binary to BCD converter that I have designed is working, but the 7 segment decoder is not.

Here are the karnaugh tables:






 

ArakelTheDragon

Joined Nov 18, 2016
1,362
The problem is most likely Proteus or the connection with the display. Like the missing of digital model pull-down or pull-up resistors. Is it common cathode, common anode, how is it connected? Is it a dot point display or not ?

Check the signals right before the display and see if you are getting what you need to get! Like 8 is "11111111".
 
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Thread Starter

Black Widow

Joined Jan 15, 2018
13
Wow!!! This is very odd. I have replaced the 7 segments with logicprobes to test the output values, and everything seems fine!!! I have tested a number of combinations, and it seems fine. I'm totally blown away, what the heck!!!

 
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