1. Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
Understanding Digital Design
The Random Number Generator
Digital Electronics
© 2014 Project Lead The Way, Inc.
Project Lead The Way, Inc.
Copyright 2009

2. Random Number Generator Digital Design - Demo
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
This presentation will
Review the Board Game Counter block diagram.
Review the circuit design of the sequential logic section of the Board Game Counter.
Review the circuit design of the combinational logic section of the Board Game Counter.
Introductory Slide / Overview of Presentation 2
Project Lead The Way, Inc.
Copyright 2009

3. Random Number Generator Block Diagram
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
Analog
Section
Sequential
Logic
Section 1 2 3 4 5 6
Combinational
Logic
Section L1 L2 L3 L4 L5 L6 L7 A B C
CLOCK
Shown is the block diagram for the Random Number Generator .
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.
Project Lead The Way, Inc.
Copyright 2009

4. Random Number Generator Block Diagram
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
Analog
Section
Sequential
Logic
Section
CLOCK A B C
Combinational
Logic
Section L1 L2 L3 L4 L5 L6 L7
Begin by looking at the sequential logic section of the Random Number Generator .
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.
Project Lead The Way, Inc.
Copyright 2009

5. Sequential Logic Section
Board Game Counter - Digital
Sequential Logic Section
Digital Electronics TM
1.3 Introduction to Digital
Schematic Diagram
3-Bit Counter
Default Count Range
(010 = 0002 to 710 = 1112) A B C
CLOCK
The schematic diagram for the sequential logic section can be divided into two parts. The first is a 3-Bit counter that is constructed from two Divide-By-Two sections. This would result in a 000 to 111 count id no SET/RESET logic. The second section is the SET/RESET Logic. When the count reaches 111 (briefly), the “D” flip-flops will SET/RESET to 001. This will result in a count range of 001 to 110 which is what is needed for the Board Game Counter. The exact detail of how this SET/RESET section works will be deferred until Unit 3 of the course.
Set / Reset Logic
Changes Count Range
(110 = 0012 to 610 = 1102)
Sequential Logic Section
Project Lead The Way, Inc.
Copyright 2009

6. Sequential Logic Section
Board Game Counter - Digital
Sequential Logic Section
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (1 of 6)
Count of “1” (A=0; B=0; C=1)
CLOCK
Sequential logic section of the Random Number Generator counting a (1).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

7. Sequential Logic Section
Board Game Counter - Digital
Sequential Logic Section
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (2 of 6)
Count of “2” (A=0; B=1; C=0)
CLOCK
Sequential logic section of the Random Number Generator counting a (2).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

8. Sequential Logic Section
Board Game Counter - Digital
Sequential Logic Section
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (3 of 6)
Count of “3” (A=0; B=1; C=1)
CLOCK
Sequential logic section of the Random Number Generator counting a (3).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

9. Sequential Logic Section
Board Game Counter - Digital
Sequential Logic Section
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (4 of 6)
Count of “4” (A=1; B=0; C=0)
CLOCK
Sequential logic section of the Random Number Generator counting a (4).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

10. Sequential Logic Section
Board Game Counter - Digital
Sequential Logic Section
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (5 of 6)
Count of “5” (A=1; B=0; C=1)
CLOCK
Sequential logic section of the Random Number Generator counting a (5).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

11. Sequential Logic Section
Board Game Counter - Digital
Sequential Logic Section
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (6 of 6)
Count of “6” (A=1; B=1; C=0)
CLOCK
Sequential logic section of the Random Number Generator counting a (6).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

12. Random Number Generator Block Diagram
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digita
Combinational
Logic
Section L1 L2 L3 L4 L5 L6 L7 A B C
Analog
Section
Sequential
Logic
Section
CLOCK
Now let’s look at the combinational logic section of the Random Number Generator .
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.
Project Lead The Way, Inc.
Copyright 2009

13. Combinational Logic Section
Board Game Counter - Digital
Combinational Logic Section
Digital Electronics TM
1.3 Introduction to Digital
Schematic Diagram A B C
Shown is the logic diagram for the combinational logic section of the Random Number Generator . Note, for simplicity, the seven lights (L1-L7) are represented by a simple logic display. Later we will replace these with Light Emitting Diodes (LED).
Combinational Logic Section
Note: Because L1 / L5, L2 / L6, & L3 / L7 are always on together, only one combinational logic circuit was required for each pair.
Project Lead The Way, Inc.
Copyright 2009

14. Combinational Logic Section
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
Truth Table A B C L1 L2 L3 L4 L5 L6 L7 - 1
“1”
“2”
“3”
Shown is the truth table for the combinational logic section of the Random Number Generator . Note that the input combinations (000=0) and (111=7) are not used because the display on the Random Number Generator would never display a zero (0) or a seven (7).
“4”
“5”
“6”
Project Lead The Way, Inc.
Copyright 2009

15. Combinational Logic Section
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
Truth Table A B C L1 L2 L3 L4 L5 L6 L7 - 1
Again, note that L1 / L5, L2 / L6, & L3 / L7 have the same entries in the truth table; therefore, they are equal functions.
Again, note that L1 / L5, L2 / L6, & L3 / L7 have the same entries in the truth table; therefore, they are equal functions.
Project Lead The Way, Inc.
Copyright 2009

16. Combinational Logic Section
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (1 of 6)
Count of “1” (A=0; B=0; C=1)
A = 0
B = 0
C = 1
Combinational logic section of the Random Number Generator displaying a (1).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

17. Combinational Logic Section
Board Game Counter - Digital
Combinational Logic Section
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (2 of 6)
Count of “2” (A=0; B=1; C=0)
A = 0
B = 1
C = 0
Combinational logic section Random Number Generator displaying a (2).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

18. Combinational Logic Section
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (3 of 6)
Count of “3” (A=0; B=1; C=1)
A = 0
B = 1
C = 1
Combinational logic section Random Number Generator displaying a (3).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

19. Combinational Logic Section
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (4 of 6)
Count of “4” (A=1; B=0; C=0)
A = 1
B = 0
C = 0
Combinational logic section Random Number Generator displaying a (4).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

20. Combinational Logic Section
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (5 of 6)
Count of “5” (A=1; B=0; C=1)
A = 1
B = 0
C = 1
Combinational logic section Random Number Generator displaying a (5).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

21. Combinational Logic Section
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
Functional Test (6 of 6)
Count of “6” (A=1; B=1; C=0)
A = 1
B = 1
C = 0
Combinational logic section Random Number Generator displaying a (6).
Logic ‘0’
Logic ‘1’
Project Lead The Way, Inc.
Copyright 2009

22. Combinational Logic Section Using LEDs
Board Game Counter - Digital
Digital Electronics TM
1.3 Introduction to Digital
LED – Light Emitting Diode
A = 1
B = 0
C = 0
Shown is the logic diagram for the combinational logic section of the Random Number Generator with light emitting diodes (LED) for the seven lights (L1-L7)
Shown with a count of “4” (A=1; B=0; C=0)
Project Lead The Way, Inc.
Copyright 2009

23. Random Number Generator Digital Section
Board Game Counter - Digital
Random Number Generator Digital Section
Digital Electronics TM
1.3 Introduction to Digital
Sequential
Logic
Section
Combinational
Logic
Section
Analog Section
The complete sequential and combinational logic section of the Random Number Generator .
Discussed in the previous lesson
Project Lead The Way, Inc.
Copyright 2009