Help needed on 7-Segment Display.

[anura92]

I am given task:

Design an octal-to-7-segment common cathode decoder for digits 0 to 5 only using the least possible number of basic gates (i.e. an optimum design). The 7-segment will only need to display from octal digits 0 to 5, ignore other numbers Your solutions must show all the design steps taken, i.e. a description of the task, requirements definition, design approaches such as truth-table(s), simplification using K-maps or Boolean theorems, and the implementation (circuit diagrams) using standard logic symbols.

I have come out with the truth table. But I'm clueless about the basic gates needed, simplification using K-maps or Boolean theorem,

3 switches name A, B, C.
so when the switches are:
* A=off/0 B=off/0 C=off/0 *, the display will be 0
* A=off/0 B=off/0 C=on/1 *, the display will be 1
* A=off/0 B=on/1 C=off/0 *, the display will be 2
* A=off/0 B=on/1 C=on/1 *, the display will be 3
* A=on/1 B=off/0 C=off/0 *, the display will be 4
* A=on/1 B=off/0 C=on/1 *, the display will be 5

Would REALLY REALLY appreciate if anyone can help.

 

[crutschow]

So they haven't taught you anything about K-maps or the Boolean theorem? If you are clueless about them I suggest you do some reading.

You need to expand your truth table to show which display segments need to be lit for each of the numbers.

 

[anura92]

Hi, thanks for the reply.

They have taught me about K-map and Boolean theorem. But i do not have any idea of applying it to the truth table results. For the truth table i am only required to diaplay 0-5 on the 7segment display.

I am using NI multisim to design the circuit. I tried but i can't get the correct out come

https://www.flickr.com/photos/64214999@N05/5847860619/sizes/l/in/photostream/

Thank you