1. What is a microprocessor? LSI chip that contains the central processing unit
2. What is a microcontroller? small micro computer used as a dedicated controller for a machine,
a piece of equipment, or a process
3. What is an FPGA? Field programmable gate array a class of PLDS that contain an array of more
complex logic sales that can be very flexibly interconnected to implement high level logic
circuits
4. 4 What does the initials IDE stand for? Integrated development environment
5. What is an HDL? A text based method of describing digital hardware that follows a rigid syntax
for representing data objects and control structures
6. What is the fundamental difference between an HDL and other programming languages?
HDL describe the hardware configuration of a circuit and programming languages that
represent a sequence of instructions intended to be carried out by a computer to accomplish
some task
7. What does the term syntax mean?
The rules defining keywords in their arrangements, usage, punctuation, and format for a given
language
8. Provide some examples of variable name syntax that is not allowed ?
Spaces , may not start with a digit or underscore , it may not end with an underscore ,
and double underscores are not permitted.
9. What does the keyword entity provide?
Entity gives a name to this circuit block
10. What does the key word port do?
Tells the compiler that we are defining inputs and outputs to the circuit block
11. How do I make comments in VHDL
The architecture declaration is used to describe the operation of everything inside the block
12. How many modes of operation are there. Explain them.
3, it is input, output, or both
13. What are the predefined VHDL data types?
the type of first the number of bits and how those bits are grouped and interpreted. The type
the term is the range of possible values
14. Why is an assignment statement called concurrent?
any statements between begin and end are evaluated constantly and concurrently
15. What are intermediates signals identified as?
Test points or nodes
16. What is a sequential circuit? (271)
is sequential circuit is 1 in which the outputs follow a predetermined sequence of states, with a
new state occurring each time a Clock pulse occurs
17. How is a memory element created? (238)
In memory element can be created by applying the concept of feedback. Feedback is
accomplished by connecting certain gate outputs back to the appropriate gate inputs
18. What is a fundamental memory element called? (238)
Flip flop
19. The most basic fundamental flip flops are created from what gates? (239)
NAND or nor gates
20. Active low or high assertion? (242)
Active low
21. What is the phenomenon called contact bounce? (243)
It is almost impossible to obtain a clean voltage transition from a mechanical switch because of
the phenomenon called contact balance
22. Explain the difference between asynch and synchronous operation of digital systems (251)
synchronous systems the outputs of logic circuits can change state anytime one or more of the
inputs change period an asynchronous system, flip flop inputs that can affect the operation of a
flip flop independent of the synchronous and Clock inputs
23. What is meant by setup time? (253 , 267)
set up time is the time interval in immediately preceding the active transition of the Clock signal
during which the control inputs must be maintained at the proper level
24. What is meant by hold time? (253)
whole time is the time interval immediately following the active transition of the Clock signal
during which the synchronous control input must be maintained at the proper level
25. What is propagation delay? (268)
Delay from the time a signal is applied to the time when the output makes it change
26. Explain how a transparent latch works. (262)
Output XYZ from a logic circuit are to be transferred to flip flops Q1, Q2, and Q3 for storage. 3
bits X, Y, and Z are all transferred simultaneously.
27. Explain what type of control and what type of input the preset and clear are? (265)
They are asynchronous inputs. These are active low inputs
28. What could happen if manufacturers specification for clock pulse low or high is not
maintained? (268)
Failure to meet these minimum time requirements can result in unreliable triggering.
29. Name a common solution to negate switch bounce? (244)
Move the switch from position one to position 2.
30. Describe the main difference between asynchronous and synchronous counters.
The main difference between asynchronous and sychronous is that flip flops do not change states in
exact synchronism with the apply Clock pulses
31. If I had an input clock of 10Mhz and am flip flop with a propagation delay of 100nS with a MOD
8 ripple counter. Will the counter work?
yes
32. What is my frequency out at the Most significant counter of a MOD16 counting circuit with an
input clock of 20Mhz?
1.25mHz
33. How many flip flops would I need and what would the inputs (a representing the lsb Q output)
be to the NAND gate for clearing the flip flops if desired a MOD 30 counter?
Five flip flops and 2 NAND gates
34. What is the purpose of the AND gates in a synchronous counter circuit? (417 418)
So the flip flop will only toggle when a = B = 1
35. What is the total delay calculation for a synchronous counter? (418)
total delay = FF tpd plus an gate tpd
36. What is an application for a MOD 60 counter? (425)
It's needed to divide 60 Hertz line frequency down to 1 Hertz.
37. What is an application for a MOD 10 Counter (425)
An application where pulses or events are to be counted and there were soltz displayed on
some type of decimal numerical readout.
38. Explain the purpose and the active level for the following pins on a 74LS163
A. ENT
anded with the ENP to control the count function
B. ENP
must be high for the counter to indicate with the arceo output that it has
reached its terminal state
C. RCO
it tells the other outputs to recycle the counter to 000
D. CLR
so the counter will start counting up again
E. PRE
39. Explain what is meant by the term cascading?
Connecting logic circuits in a serial fashion with the output of one circuit driving the input of
the next and so on
40. If I purchased a presettable counter what does that mean? (428)
counter that can be preset to any starting count either synchronously or asynchronously
41. How do I turn a up counter into a down counter?
Use the inverted flip flop outputs to control the higher order J, K inputs