how to design 8 bits xor and xor circuit?

[iceberg25]

How to design a simple calculator.?

hi, very stress now ......
how to design a A(4 bits ) xnor /xor B(4bits) circuit?
who can help me ? thx.

 

[ericgibbs]

hi, very stress now ......
how to design a A(4 bits ) xnor /xor B(4bits) circuit?
who can help me ? thx.

hi,
Look at this forum thread:

https://www.electro-tech-online.com...s-about-a-xor-logic-gate.34806/?highlight=xor

Read Dean Huster post.

Do a search on the forum for XOR, a number of threads are discussing the problem.

If you get stressed, walk away from the problem for 10 minutes and have a cup of coffee...

 

[iceberg25]

well ,i think this is not what i want.
anyway thanks.
i am now want to design a simple calculator that have 12 function,xor and xnor is 1 of the 12 functions.
our calculator input is just 4 bits and have 2 inputs(A and B).
So how to get this 2 inputs in xor and xnor function?
the outputs will have how many bits?

 

[superbrew]

If I understand you correctly, you can just use an XOR on each bit, ie. A1 XOR B1, A2 XOR B2, etc. This will give 4 bits on the output.

 

[iceberg25]

yup,this is the only way that i can do before the more useful circuit i can find it.hope that have more idea from this forum

 

[Nigel Goodwin]

I'm not very sure really what you're trying to do?, you say you're building a 12 function calculator - are you doing this entirely in hardware?.

Way back when, the UK magazine Practical Electronics did a project series on building a calculator (four function I think?), it ran to something like 9 issues or so - used hundreds of TTL IC's and would have cost a fortune to make.

Unfortunately, part way through the series the first handheld calculators came out, by using a micro-processor/micro-controller they reduced the IC count to only a tiny handful, and the cost to very little.

 

[iceberg25]

well,this is a task that my lecturer us to design it .
so ,i really don't know how to design it by using simple logic gate.

 

[Nigel Goodwin]

Can you post the task exactly as it was given to you? (but in English).

 

[iceberg25]

no exact topic given.he just ask us to do a simple calculator that must have 12 function ,the xor and xnor are just 2 of the function of 12.the input is just 4 bits and have 2 inputs.for example,input A (4bits) add input B(4bits),and the output will be diplay in screen(7 segment display) when will enter it.

 

[Nigel Goodwin]

Does that mean you can use a micro-controller then?.

 

[iceberg25]

is it possible that we dint use any micro-controller to design a simple calculator? i think we should use simplest component to create it.actually ,my lecturer just want to see the circuit design and not the actual hardware.anyway~thanks to all that give me idea.

 

[iceberg25]

nobody wanna help me???
who can provide me a complete circuit?
the function should haver,and,not,xnor,xor,+,_,*,/,right shift,left shift,and others.....
thx.

 

[Nigel Goodwin]

Like I said above, with a micro-controller it's fairly trivial, with just hardware it's a long way from trivial - but your assignment is far too vague, and no one is going to design a multi-PCB, dozens of IC's (if not hundreds), project for you.

A teacher wouldn't just dump something like this on you, presumably it's got some bearing on what you've been taught in class.

 

[ericgibbs]

hi iceberg,
Have a look at this link, the first half of the document should give you an idea of the complexity of the project you are working on.

To fully answer your question would take a lot of work.

Which course are you taking at college and what level are you at.?

https://www.ee.ucl.ac.uk/~ademosth/E757/Topic1.pdf

 

[iceberg25]

well, i am taking electrical engineering in my university.
i had try my best to design the circuit out ade but now ,i just wonder how to draw the circular right shift ,circular left shift and incremental function's circuit in my simple calculator.who still got the idea wanna contribute to me???
hehe,thx ya~

 

[ericgibbs]

well, i am taking electrical engineering in my university.
i had try my best to design the circuit out ade but now ,i just wonder how to draw the circular right shift ,circular left shift and incremental function's circuit in my simple calculator.who still got the idea wanna contribute to me???
hehe,thx ya~

hi,
Have a look at these links for R/L shift registers.

http://www.ee.ucl.ac.uk/~ademosth/E757/Topic4.pdf

**broken link removed**

http://en.wikipedia.org/wiki/Bitwise_operation

http://www.answers.com/topic/shift-register?cat=technology

I hope you do well in your studies.

Do you have any drawings that you could post.?

 

[iceberg25]

well,i think i have the fundamental ade,but the problem is how to apply in a calculator.
erm.....i dont have scanner ,so i cant scan my drawing to u.
i think 2 more days i will draw it with computer if i had complete the circuit.

 

[ericgibbs]

well,i think i have the fundamental ade,but the problem is how to apply in a calculator.
erm.....i dont have scanner ,so i cant scan my drawing to u.
i think 2 more days i will draw it with computer if i had complete the circuit.

If you Google for ExpressPCB, you can download a free schematic drawing program also a free pcb layout program.

Direct is www.expresspcb.com

https://www.softpedia.com/get/Science-CAD/ExpressSCH.shtml

 

[iceberg25]

ok,i will try it.
but really dont have any idea to contribute me??
are u still a university student??

 

[ericgibbs]

ok,i will try it.
but really dont have any idea to contribute me??
are u still a university student??

hi iceberg,

No, I am not still a university student, I am a 75 year old, semi-retired Chartered Electronics engineer.

We are trying to help you with your project, but the amount of work required to give you all the details regarding the build an old style calculator, covering all 12 of the basic functions you require, is far to beyond the scope of a web forum.

I am puzzled why your teacher/instructor has given you this assignment, its going to take a very long time to complete. When is he expecting the assignment to be completed.?

I know that you are preparing a drawing to post to the forum, I look forward to seeing it.


Please dont read my reply as being negative..

I have carried out a lot of web searching, trying to find a site that will give you the answers, no luck so far..