Understanding Analog Design The Random Number Generator Digital

Random Number Generator Analog Design - Demo 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 A Analog Section CLOCK Sequential Logic Section 0 0 0 1 1 1 B 0 1 1 0 0 1 C 1 0 1 0 Combinational Logic Section L 1 L 2 L 3 L 4 L 5 L 6 L 7 1 2 3 4 5 6 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. 3

Random Number Generator Block Diagram A Analog Section CLOCK The Analog Section produces a dampened square wave that “rolls” the count and slowly stops. Sequential Logic Section B C On every pulse of the clock, the Sequential Logic Section increments a binary count from 1 to 6, then repeats. Combinational Logic Section L 1 L 2 L 3 L 4 L 5 L 6 L 7 The Combinational Logic Section encodes the binary count into the die’s seven dots. 4

Random Number Generator Analog Section Schematic Diagram CLOCK 5

A Simplified Version • When the push button switch is pressed, the 100 uf capacitor (C 1) will quickly charge to 5 volts through the 1. 2 k resistor (R 8). • As long as the push button switch remains pressed, top end of the 10 k resistor (R 9) will be held at 5 volts. This results in a simplified version that is equivalent to a standard 555 time oscillator. Actual Version Simplified Version 6

Analysis of Simplified Version Period: RA RB A Frequency: C 7

Simulation of Simplified Version VOUT VC 8

Simplified Version – Timing Analysis VOUT VC Period: Frequency: 9

The Actual Version • 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 100 u. F capacitor (C 1) and the 1. 2 k resistor (R 8) play a role. Actual Version 10 Simplified Version

Simulation of Actual Version Push Button Pressed Push Button Released VOUT VC VLimit 11

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). Push Button Pressed Push Button Released VOUT VC VLimit A B C • Eventually the oscillation will stop. 12

Timing Analysis at Time A Period: Frequency: A 13

Timing Analysis at Time B Period: Frequency: B 14

Timing Analysis at Time C Period: Frequency: C 15

Random Number Generator Analog Section Sequential Logic Section Combinational Logic Section 16 Discussed in a future lesson