Exam 3 - BK Flashcards
(143 cards)
1
Q
What are the two digital logic states?
A
Logic 1 (ON)
Logic 0 (OFF)
2
Q
How many bits in a Byte?
A
8
3
Q
How many bits is a Nibble?
A
4
4
Q
What are the two advantages of Digital signals?
A
- Error detection and correction (MOST IMPORTANT)
- Stored memory in semiconductors
5
Q
What does ADC stand for
A
Analogue to Digital
6
Q
What does DAC stand for
A
Digital to Analogue
7
Q
List 2 common ADC circuits
A
- Successive Approximation Register (SAR)
- Dual Slope
8
Q
What is the basic operation of an ADC
A
Converts an analogue signal voltage to a string of binary code depending on the value of the analogue input voltage
9
Q
If the inputs to an AND gate are 1 & 0, what is the output
A
0
10
Q
If the inputs to an OR gate are 1&1, what is the output
A
1
11
Q
How many inputs and outputs are there in a NOT gate
A
1 Input, 1 Output
12
Q
What is another name for a NOT gate?
A
Inverter
13
Q
On a XOR gate, when the input is 1&1, what is the output
A
0
14
Q
What is Fan-In
A
The number of inputs a logic gate can accept
15
Q
What is Fan-Out
A
The number of inputs a logic gate can drive
16
Q
What must be used if a logic gate has a High Fan-In of more than 10 inputs
A
A buffer
17
Q
What is the disadvantage of a High Fan-In logic gate
A
Slower due to its complexity
18
Q
What is the normal Fan-out output of any logic gate, and how can it be expanded?
A
Normal Fan-Out = 10
Can be expanded with a buffer
19
Q
What is propagation delay?
A
Time required for a digital signal to travel from input to output
20
Q
What problems does propagation delay cause in an asynchronous circuit?
A
Intermittent faults
21
Q
Does propagation delay increase or decrease with temperature
A
Increase
22
Q
Does propagation delay increase or decrease with output load increase
A
Increase
23
Q
In a logic circuit, what are some advantages in keeping the number of components to a minimum?
A
- Keep costs low
- Reduce complexity
- Reduce size of power supply
- Reduce propagation delay
24
Q
What is the most basic flip-flop that all other bi-stable latches and multi-vibrators are made from?
A
SR Flip Flop
(Set-Reset)
25
What does the term "Transparent" mean when talking about flip-flops?
Output responds immediately to input
26
Are SR Flip-Flops Synchronous or Asynchronous?
Asynchronous
27
How many inputs and outputs does and SR Flip-Flop have?
2 Inputs (Set-Reset)
2 outputs (Q - notQ)
28
Which 3 ways can the clock signal be read?
Edge Trigger:
-Positive Edge (Rising)
-Negative Edge (Falling)
Level Trigger:
- When clock pulse reaches a certain logic level (Usually 1)
29
How is a Gated SR Flip-Flop different from a standard SR Flip-Flop?
A clock signal input
30
How many inputs in a Gated SR Flip-Flop?
3 Inputs:
-Set
-Reset
-Clock (Enable) Input
31
What is the disadvantage to a Gated SR Flip-Flop that is fixed by adding inputs 'Preset and Clear'
Uncertainty in switching
32
What is a disadvantage to a Gated SR Flip-Flop w/Preset&Clear that is fixed by using a D-type Flip-Flop?
Using a D-type Flip-Flop eliminates need for having 2 additional input for Preset and Clear by connecting an inverter between Set and Reset (or between J and K)
33
How many inputs to a D-type Flip-Flop?
2 Inputs:
Clock and 'D' input
34
How is a Master-Slave Flip-Flop constructed?
2 bi-stable SR circuits connected in a cascade
35
How does a T-Type Flip-Flop work?
Output changes state every application of a clock signal and latches onto that signal until another input signal is added
36
What can the T-type Flip-Flop also be used for?
Frequency Divider - Output frequency is half of input frequency
37
In a JK Flip-Flop, what happens when both J and K are 1
Q toggles
38
What does Clear and Preset do?
Cleared to 0 or Preset to 1 independently of clock signal
39
Is D-type transparent?
Yes
40
Where is the inverter placed in a data flip flop?
In-between S and R inputs
41
What are some uses for T-type?
Frequency Divider
Binary Counter
42
Is T-type commercially available?
No, can be made by connecting the J and K inputs together
43
What output condition must be avoided in a SR Flip-Flop?
S=0
R=0
- Invalid Output
44
What Flip-Flop was made to overcome the S=R=0 condition in a SR Flip-Flop?
JK Flip Flop
(Added clock signal)
45
What are the 4 outputs conditions of a JK Flip-Flop?
Logic 1
Logic 0
No Change
Toggle
46
What does the JK Flip-Flop suffer from?
It suffers from the timing problem dubbed 'Race'
47
How is 'Race' in a JK Flip-Flop overcome
By keeping the timing pulse as short as possible by reducing the period.
This is done by increasing frequency.
48
What Flip-Flop is used to eliminate timing problems in a JK Flip-Flop?
Master-Slave Flip-Flop
49
Where does the Master circuit trigger on the clock pulse?
Triggers on positive edge of clock pulse
50
When does the Slave circuit trigger on the clock pulse?
Triggers on the negative edge
51
Where does the feedback go to on a Master-Slave circuit?
The output of the Slave circuit is fed back to the Master circuit
52
Is the Master-Slave Flip-Flop Synchronous or Asynchronous?
Synchronous
53
What is the most common use for a Square Wave?
Clock and Timing Signal
54
What is the duty cycle of a square wave?
50% duty cycle
55
What is the equation for finding the frequency of a square wave?
Frequency = 1 / (ON time + OFF time)
56
Is a rectangular wave symetrical?
No nigga
57
What is another name for the Positive and Negative wave half on a rectangular wave?
Mark and Space
58
What are rectangular waves used for in a circuit?
- Regulating power
(Higher duty cycle = Greater power applied)
- Pulse Width Modulation
59
Are triangular waves symetrical?
Yes
60
What is the duty cycle of a triangular wave?
50%
61
Is a sawtooth wave symetrical?
No
62
What are sawtooth waves rich in?
Harmonics
63
What type of sawtooth wave is the most common?
Positive Ramp
64
What is the purpose of Triggers and Pulses?
To control the timing in a circuit
65
What are the characteristics of a Trigger?
- Very narrow pulse
- Swings either positive or negative
66
What are the characteristics of a Pulse?
- ONLY POSITIVE
- Shape of the pulse is determined by Mark-to-Space ratio
- Similar to a rectangle wave
67
What is a Schmitt Trigger used for?
Creating a clean square wave from an input
68
What 3 waves can a function generator make?
- Sinusoidal
- Triangle
- Square
69
How many inputs on a Schmitt Trigger
1 - Clock input
70
How many times does Q0 change state per line?
Every line
71
How many times does Q1 change state per line?
every 2 lines
72
How many times does Q3 change state per line?
every 8 lines
73
How many times does Q2 change state per line?
every 4 lines
74
What Flip-Flop configuration do counters use?
T-Type
(Toggle mode)
75
What does 'mod' mean when used in a counter
number of states
76
What are the two types of counters?
Asynchronous
Synchronous
77
What does a counter do?
It is a digital circuit which produces a Binary count
78
What does Asynchronous mean?
The clock pulses to the Flip-Flop arrive at different times
79
What does Synchronous mean?
Each Flip-Flop is clocked in at the exact same time
80
What is another name for an Asynchronous counter?
Ripple counter
81
What is a disadvantage to Asynchronous counters?
Takes time for the change of the clock pulse to change the output.
The device has to wait to count the 'ripples' before it can be used.
82
On what edge of the clock pulse is the UP counter changing states
Negative edge
(falling edge)
83
What does an UP/DOWN counter count?
Counts both up and down
84
On an UP/DOWN counter, how does it count up?
The Q output is steered to the next flip-flop's clock
85
On an UP/DOWN counter, how does it count down?
The notQ output is steered to the next flip-flop's clock
86
What makes a frequency divider useful for being used as a counter?
Because the Q outputs are multiples of the clock frequency, they can be used as a counter.
87
What is a general rule for the number a frequency divider can count?
The counter will divide by one more than it can count to
88
What are the 4 different types of Registers?
- Storage (Retains info but does not alter it)
- Shift (Moves it left/right)
- Series (Serial data is entered or removed1 bit at a time)
- Parallel (All the bits are entered or removed simultaneously
89
What is a Register?
Temporarily stores information using Flip-Flops
90
What is a Buffer Register?
Serves as a temporary store when transferring data between two units with different speeds or doing independent tasks
91
How is a Buffer Register made using flip-flops?
Parallel in - Parallel out
92
What are Shift Left/Right Registers
Allows data to be shifted left OR right by multiplying or dividing by the power of 2
93
How are Shift Left/Right Registers configured?
As D-Type flip flops
94
What are the two families used on Digital ICs
1. CMOS (Complementary Metal-Oxide Silicone)
2. TTL (Transistor-Transistor Logic)
95
What is the internal circuitry of CMOS ICs based off?
MOSFETS and FETS
96
What is the internal circuitry of TTL ICs based off?
NPN and PNP Bipolar Transistors
97
What is the advantages and disadvantages of CMOS
Advantages:
- Very low power consumption
- low propagation
Disadvantages:
- Slower operating speeds
98
What is the advantages and disadvantages of TTL
Advantage:
- Much faster operating speed
Disadvantage:
- Very high power consumption
99
What applications can CMOS be used for?
1. Low power battery circuits
2. High Frequency Tuning operation for switching speeds upwards of 100MHz
100
What is the 3rd output state added to ICs to allow them to be connected together with different output states?
High Impedance state (Hi-Z)
101
In Boolean logic, what does True (T) mean?
Logic 1, High
102
In Boolean logic, what does False (F) mean?
Logic 0, Low
103
What is the state in-between HIGH and LOW which has an unpredictable output which noise can affect?
No-mans land
104
What does the term source and sink mean?
weather a circuit is being supplied or is drawing from a previous or future stage
105
What are the 4 functional blocks of a Microprocessor?
- Store/Memory
- Control
- Arithmetic and Logic Unit (ALU)
- Input/output (I/O)
106
What is the integrated package of Microprocessors called?
- MPU (Microprocessor unit)
- CPU (Central Processing unit)
107
What is the purpose of busses in a Microprocessor?
Provides a path for the flow of information
108
What is the purpose of an I/O interface?
Provides a connection to the outside world
109
What is the definition of an Instruction?
An instruction is a number of discreet operations a computer is told to perform a given task
110
What is a Program?
A group of instructions that allows the computer to perform a specific task
111
What is a Computer Word?
A group of binary digits (Bit and Bytes) that occupy storage memory
112
What is an example of a Word Length?
8bit, 16bit, 32bit, 64 bit
113
What are the 3 Busses in a Microprocessor?
- Address Bus
- Data Bus
- Control Bus
114
What does the Address bus do?
Carries info from the CPU to the I/O to ensure the correct device is accessed
- UNIDIRECTIONAL
115
What does the Data bus do?
Carries instructions to CPU
- BIDIRECTIONAL
116
What does the Control Bus do?
Carries control signal from the CPU to the Memory and I/O to ensure it arrives at the CORRECT TIME
- UNIDIRECTIONAL
117
What is the most important section to a Microprocessor?
The Arithmetic Logic Unit (ALU)
118
What is the accumulator in a Microprocessor?
Main working register to store data
119
What is the Data Register in a Microprocessor?
Temporary storage for data coming from or going to the Data bus
120
What is the Instruction Decoder in a Microprocessor?
Converts the instructions (Binary) into the appropriate control information to the MPU
121
What is the Program Counter in a Microprocessor?
Keeps track of a program to ensure it follows in the CORRECT SEQUENCE
122
What is an Operand?
Data words that (aren't instructions codes) operated on by an ALU
123
What is an Opcode?
Binary (or Hex) word which represents a Microprocessor instruction
124
What does a Volatile memory mean?
The contents of the data are lost after the power is removed
125
What does a Non-Volatile memory mean?
The contents of the data are not lost after the power is removed
126
Is RAM volatile or non-volatile?
Volatile
127
What are the two categories or RAM?
- Static RAM
- Dynamic RAM
128
How is info stored on Static RAM?
An array of Flip-Flops (either Bipolar or MOS)
129
For Static RAM, Is Bipolar or MOS faster?
Bipolar is faster but uses more power
130
How is info stores on Dynamic RAM?
In an array of capacitors
131
What is a downside to storing information in an array of capacitors?
Capacitors lose charge via leakage.
- It must be refreshed every few milliseconds, this requires additional circuitry
132
Which of the two types of RAM is best?
Dynamic RAM
- Faster, cheaper, uses less power
133
What does ROM stand for?
Read Only Memory
134
Is ROM volatile or non-volatile?
ROM is Non-Volatile
135
What are the 4 types of ROM
- Masked Programmed ROM
- Programmable ROM (PROM)
- Erasable PROM (EPROM)
- Electrically Alterable PROM (EAPROM)
136
What are the two types of ROM that cannot be altered?
- Masked Programmed ROM
- Programmable ROM (PROM)
137
Which types of ROM can be altered?
- EPROM
- EAPROM
138
How is a program stored in a Masked Programmed ROM?
Stored during manufacture to perform a dedicated function.
- Expensive unless done in a mass manufacture
139
How is information stored in a PROM?
Short pulses of high current pass through small resistive links and fuse them permanently.
140
How is a program erased on an EPROM?
Exposing EPROM under intense UV light erases ALL data stored (can be a downside)
141
What ROM should be used if only a portion of the data is to be altered?
EAPROM
- Small areas can be altered electrically instead of altering the whole fucking lot
142
What is firmware?
A special type of software that is RARELY CHANGED
143
