# 4 bit binary adder

Thread Starter

#### Dhong_04

Joined May 4, 2022
3
Hi, I need to make a block diagram where the inputs are 2 4-bits input displayed in 7-segment display (each input will use 2 7-segment display as the decimal equivalent range from 0-15), and the output should show the sum of the inputs displayed in 7-segment display (Use 2 7-segment display as the highest possible sum is “30”)

#### dl324

Joined Mar 30, 2015
14,710
Welcome to AAC!

Did you have a question?

Thread Starter

#### Dhong_04

Joined May 4, 2022
3
Hi! I would like to ask if how can I make a block diagram where there are inputs of 2 4-bits input displayed in 7-segment display where each input will use 2 7-segment display as the decimal equivalent range from 0-15, and the output should show the sum of the inputs displayed in 7-segment display we should use 2 7-segment display as the highest possible sum is “30”? How can I make it on multisim? Thank You!

#### dl324

Joined Mar 30, 2015
14,710
A block diagram is simple. You just draw boxes, label their functionality, and represent the inputs or outputs. For convenience, multiple bit inputs can be compressed to a single bus (input) with an indication of how many bits it represents.

Are you supposed to use only logic gates for your implementation? Or are you allowed to use commercial parts available in Multisim? I can't help you with Multisim. It isn't a free simulator and the free version (Multisim Blue or something like that) no longer works.

It may sound simple but displaying 4 bit binary numbers as BCD on 2 7-segment isn't as trivial as one might think.

Thread Starter

#### Dhong_04

Joined May 4, 2022
3
We are allowed to use the components and other things that multisim have. You're right that it is somehow trivial and complicated. But, thank you for your response! I appreciate your effort of answering my queries!

#### dl324

Joined Mar 30, 2015
14,710
If you want assistance, you have to show your best effort so we can see where you're having difficulty and can offer guidance.

The only thing that isn't trivial is converting binary to BCD. There was a ROM-based commercial part (74185), but it's no longer available. Multisim might have the part, but that would make it the exception.

#### Papabravo

Joined Feb 24, 2006
18,840
Here is a sample of two four bit adders that subtract every possible value of an 8-bit counter from 0 to make a down counter.

#### dl324

Joined Mar 30, 2015
14,710
Here's an example of a block diagram from an Intel memory databook:

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