# Engineering:Digital Design

Information given:
1) 2 X 8-bits input A and B
2) 1 X ?-bits function selector input
3) 1 X 8-bits output C
4) 1 bit overflow (designed as “flag O” )

Function selector are made up of:
1) A + B operation 7) A NOR B
2) A – Boperation 8) A XNOR B
3) A AND B 9) A RIGHT SHIFT (by) B
4) A OR B 10) A LEFT SHIFT (by) B
5) A XOR B 11) A CIRCULAR SHIFT L & R (by) B
6) A NAND B 12) Incremental of A + B

Explanation for function selector 12):

When input A + B , the output C will start from A  A +1  A + 2 A +3 ... A+B

Show the incremental value from A to A + B using programming and the timing delay is 1sec

Summary of operation:

Display Input A Display Input B Display Output C LED
Timer

1 2 3 ON
4 5 6 OFF

7 8 9 RESET
0 A B ENTER
X X X
X X X
X X X
X X X

1) The input A and B will have a 3-decimal display to represent the decimal values of the keyed-in 8-bits input
2) When input A is selected (by pressing A in the keypad) , pressing the value of input A will be displayed at the display input A after pressing “ENTER”.
3) Step 2 is the same for input B
4) After displaying input A and B, choose a function in the function selector to display output C at the display output C.
5) when an overflow is detected, the LED at display output C will be switched on.
6) for the function number 12th, Timer must display the timing delay of 1sec

Problems:
1) How many bits of function selector should be used? Explain why.

2) Design a full logic circuit diagram of this entire operation. Must show all the logic gates involved
Tips: ( must have Multiplexer , demultiplexer , decoder, encoder ,shift register, 7-segment display , memory(RAM or ROM) ,ALU , timer and other suitable logic circuit)

3) what is the typical operating voltage for this circuit? Frequency?

Extra question:
1) as the maximum value of decimal for 8-bits is 255, what would happen if a higher value of decimal is keyed-in? for example, if we key in 355 in the input A, what would be displayed in the output C? Describe the response of the circuit regarding to the input.

2) Say we want to key in a number “123” to input A , but we accidentally press 124 instead. By using “RESET” in the keypad, describe the operation of the circuit when the number “4” is reset to 3. Tips:(involve Shift register and Memory)

3) When a 3-bits input A is added to 3-bits input B, the addition may cause an overflow of 1 bit,causing the LED to be switched on.We wish to know the value of the overflow bit.Describe how do we display the overflow bit (0,1,2…9)?
Tips: use a set of LED to show the number of the overflow.when a LED is ON,the value is 1.when a led is OFF,the value is 0.use 4 LED

Decimal value
0 0 0 0 0
0 0 0 1 1
0 0 1 0 2

1 0 0 1 9

1. 👍
2. 👎
3. 👁
1. Can you elaborate a bit on that?

1. 👍
2. 👎

## Similar Questions

1. ### Geography

Most of Earth’s landmasses are covered by a mixture of bits of rocks and bits of once-living parts of plants and animals. This material is called _____.

2. ### Math I need help ASAP!

1) Identify the function rule shown in the table. Function Table n - 3, 4, 5, 6 y - 2, 1, 0, -1 a. y = 2 + n b. y = 5n c. y = 5 - n d. not enough information ** 2) What is the values of the function y = -2x - 4 for x = 0,1,2 and

3. ### math

A bit is one eighth of a dollar how many cents is 6 bits? My answer is 6 cents? I don't think I am right.

4. ### Math

There are 15 bits and 12 girls in ms.smiths class.What is the ratio of girls to boys written as a fraction in simplest form

1. ### English

Which idea from the paragraph below is important to include in a summary? The platypus is an Australian mammal that does not fall neatly into a classification. It is one of only two mammals (the other being the echidna) that bear

2. ### PROGRAMMING

Laboratory Work No. 1 Memory Representations of Primitive Data In this laboratory work, you should research and find a solution (proved by C code) for each task below: a) How many bits a byte equals to? b) How many bytes a basic

3. ### ed-tec

What is the Multiple Source Test? A. checking to make sure that information can be found in more than one place B. a fact checking software that tests information found on the Internet C. an amendment that states that all

4. ### Math

Hey, I need your help! I have an input output table that I need the function rule for. The table is like this: Input: 0 Output: 25 Input: 100 Output: 35 Input: 200 Output: 45 Input: 300 Output: 55 Input: 400 Output: 65 PLEASE I

1. ### Bit rate and probability

Attention, please show the calculations in details, comments have to be provided. You have information source with M symbols. 1. Calculate the amount of the information in bits for one M-ary symbol, considering that the

2. ### Physics-Help-I'm Stuck

If a balloon is made of Mylar(alumized plastic) instead of rubber, would it stick to a wall if you rubbed the balloon against a wool sweater? If a charged balloon is held a distance "d" above some paper bits they start to move. If

3. ### Probability

A binary communication system is used to send one of two messages: (i) message A is sent with probability 2/3, and consists of an infinite sequence of zeroes, (ii) message B is sent with probability 1/3, and consists of an

4. ### Science

In a classroom experiment, a student rubs a comb against her hair. The child is then brought near bits of paper resting on a surface. Which of these can be concluded if the comb picks up bits of paper? A. The comb is an insulator,