EEE 120 Final

Which one of the following statements is incorrect?

Correct Mealy output should be sampled right after the clock edge.

In the Princeton Architecture, you can clearly tell the difference between the opcode and the data.

False

True or False a multiplexer has multiple outputs and a decoder has just a single output.

False

True or false in order to jump around in the memory you only need one register.

False

Which 3-input gate outputs a false value only when all inputs are true?

NAND

Which gate on the list is considered "functionally complete", which means that you can construct a NOT gate, an AND gate and an OR gate using a combination of only this particular gate?

NAND

There are two traditional ways of storing instructions and data in memory. The Harvard architecture separates instructions from the data upon which they operate and stores them in separate memory blocks. This scheme requires that data and instructions have independent paths by which they reach the central processing unit. In the Princeton architecture, data and instructions are stored in the same memory block; both data and instructions use the same path to the CPU. Which architecture does the processor you designed (shown below) conform to?

Princeton

Can you construct an XOR gate using only AND/OR/NOT gate(s)?

True

For a sequential circuit to be called "synchronous" the clock signals of all flip flops have to be connected in parallel.

True

True or False: If the carry bit into the MSB of the signed binary numbers being added is 1, and the carry bit out of the MSB of the signed binary numbers being added is 0 then there is an overflow.

True

Which is the minimum SOP expression for the function F(X,Y,Z) = (X + Y')' Z + (XZ)' + Y ? No partial credit is granted for incomplete simplifications.

X' + Y + Z'

Which gate generates a true output only if an odd number of inputs is true?

XOR

To design a sequence detector "0110", how many states are needed in a Mealy machine?

4

To design a sequence detector "0110", how many states are needed in a Moore machine?

5

Convert the following decimal number to hexadecimal: 88

58

How many binary digits (bits) does a Byte have?

8

Which is the correct hexadecimal number corresponding to the binary number 1010 1011?

AB

Which combinations of active Enable signals might cause a data conflict on the Data Bus if enabled simultaneously? (Hint: You might need to look at the brainless microprocessor diagram.)

ACC to Data Bus & Read

Which gate cannot be used to build a latch?

AND

"You accidentally bought the wrong chip and got an inverting three-state buffer (for example an 74LS240). What do you need to do to replicate the operation of a non-inverting three-state buffer? You should select only one answer, but multiple answers can be correct."

Add a "regular" inverter to the input of the inverting buffer.

Somebody was asked to perform an addition of the two 6-bit signed integers 100111 + 110111 by calculating the decimal equivalent of each binary number and indicating if overflow occurs. Unfortunately, the papers got messed up and now the person is struggling to find the matching solution. Can you help by indicating which one of the following answers is the correct one?

-25 - 9 = -34, overflow

What is the decimal value of the 4-bit 2's complement number 1011?

-5

Which is the correct 8-bit binary number corresponding to the decimal number 88?

01011000

Which one of the Boolean expressions describing a 2:1 Multiplexer is not identical to the others?

(A + S')(B + S)

Which of the following statement(s) are true? (Multiple correct answers are possible. Wrong answers will deduct points.)

1. A circuit with 4 inputs has 16 possible combinations (truth table lines). 2. All circuits can be created using only NOR gates. 3. You should never tie 2 outputs of two distinct circuits together.

What are you NOT allowed to do when building digital logic circuits? (Multiple correct answers are possible. Wrong answers will deduct points.)

1. Connect multiple outputs of different gates. 2. Connect an output of a logic gate to twelve inputs of different gates.

Which of the following statements about a CPU controller are true.

1. Hexadecimal numbers that are stored in ROM can be used as an opt code. 2. The first state in the CPU controller FSM is a fetch state. 3. A Decoder can be used in order to decode individual bit signals.

Which of the following statements are true?

1. K-Map and Boolean Algebra can be used to simplify circuits. 2. Equations can be derived from K-Maps using SOP and POS.

Which of the following statements about the PROM chip is true?

1. PROM stands for Programmable Read Only Memory. 2. Data to the PROM chip can only be programmed once.

Which of the following statements are true?

1. ROM stands for "Read Only Memory" 2. There is an internal feedback loop that goes from the Accumulator to the ALU.

The 2708 8 kBit EPROM is a 1024 word x 8 bit device. How many address select inputs does it have?

10 (A0..A9)

Compute the sum of the following pair of 6-bit unsigned numbers. A numerical answer in binary is requested: 01 0100 + 00 1100

100,000

What is the decimal number -54 in signed binary.

1001010

If you have a 4:16 decoder, how many possible ROM storage units can you access.

16

Convert the following unsigned binary number to decimal number: 1010 1010

170

How many Execute state(s) can a controller with a 2-bit FSM have at maximum, assuming that it has one Fetch state (i.e. do not count the Fetch state)?

3