understanding analog design the random number generator © 2014 project lead the way, inc.digital...
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Understanding Analog DesignThe Random Number Generator
© 2014 Project Lead The Way, Inc.Digital Electronics
Random Number GeneratorAnalog Design - Demo
2
This presentation will• Review the Random Number Generator block
diagram.
• Review the circuit design of the analog section of the Random Number Generator.
2
Random Number Generator Block Diagram
3
0 0 0 1 1 1
0 1 1 0 0 1
1 0 1 0 1 0
1 2 3 4 5 6
AnalogSection
SequentialLogic
Section
CombinationalLogic
Section
The Analog Section produces a dampened square wave that “rolls” the count and slowly stops.
On every pulse of the clock, the Sequential Logic Section increments a binary count from 1 to 6, then repeats.
The Combinational Logic Section encodes the binary count into the die’s seven dots.
CLOCK
L1L2L3L4L5L6L7
A
B
C
4
AnalogSection
CLOCKCombinational
LogicSection
The Analog Section produces a dampened square wave that “rolls” the count and slowly stops.
On every pulse of the clock, the Sequential Logic Section increments a binary count from 1 to 6, then repeats.
The Combinational Logic Section encodes the binary count into the die’s seven dots.
L1L2L3L4L5L6L7
SequentialLogic
Section
A
B
C
Random Number Generator Block Diagram
5
Schematic Diagram
CLOCK
Random Number Generator Analog Section
A Simplified Version
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• When the push button switch is pressed, the 100uf capacitor (C1) will quickly charge to 5 volts through the 1.2 k resistor (R8).
• As long as the push button switch remains pressed, top end of the 10 k resistor (R9) will be held at 5volts. This results in a simplified version that is equivalent to a standard 555 time oscillator.
Actual Version Simplified Version
Analysis of Simplified Version
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nF 470 C k 18 R k 10 RBA
mSec 982.14T
nF 470 k 182k 10 693.0T
C R2R 693.0TBA
Hz 66.74 ƒmSec .T
ƒ
98214
11
Period:
Frequency:
RAA
RB
C
Simulation of Simplified Version
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VOUT
VC
Simplified Version – Timing Analysis
9
mSec 15T
Hz 66.66 ƒmSec
ƒ
Tƒ
151
1
Period:
Frequency:
VOUT
VC
The Actual Version
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• When the push button switch is pressed and held, the actual analog section of the Board Game Counter performs like a standard 555 time oscillator. However, for the Board Game Counter to operate correctly, the oscillation must slow and eventually stop.
• This is where the 100uF capacitor (C1) and the 1.2 k resistor (R8) play a role.
Actual Version Simplified Version
Simulation of Actual Version
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VOUT
VC
VLimit
PushButton Pressed
PushButton Released
Actual Version – Timing Analysis
• When the push button is pressed, the 555 Timer produces a 66 Hz square wave.
• Once the push button is released, the frequency gradually decreases (period increases).
• Eventually the oscillation will stop.
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VOUT
VC
VLimit
PushButton Pressed
PushButton Released
A CB
Timing Analysis at Time A
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A
mSec 536.15T
Hz 64.36 ƒT
ƒ
1
Period:
Frequency:
Timing Analysis at Time B
14
B
mSec 50.27T
Hz 36.36 ƒT
ƒ
1
Period:
Frequency:
Timing Analysis at Time C
15
C
mSec 429.51T
Hz 19.44 ƒT
ƒ
1
Period:
Frequency:
16
SequentialLogic
Section
CombinationalLogic
Section
Analog Section
Discussed in a future lesson
Random Number Generator Analog Section