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Revision as of 12:30, 13 October 2005

The step-by-step procedure

Here you can find a detailed description of the state transitions that occur in the counter. The counter has four states, R1 to R4.

• start state

S is active, R1 is active

• transition to state R2

S is deactivated, R1 is still present (but fading) and represses R4. R2 gets produced

• state R2

S is inactive, R2 is active

• transition to state R3

S is activated, R2 is still present (but fading) and represses R1. R3 gets produced

• state R3

S is active, R3 is active

• transition to state R4

S is deactivated, R3 is still present (but fading) and represses R2. R4 gets produced

• state R4

S is inactive, R4 is active

• transition to state R1 (start state)

S is activated, R4 is still present (but fading) and represses R3. R1 gets produced

• ...and we return to the start state

S is active, R1 is active

breakdown into modules

The counter can be partitiond into two (fairly) independent devices:

• Input Module
• NOR Module

Both are designed as PoPS input - PoPS output devices (as specified in the MIT nomenclature)

Input Module

In this device, we want to capsule the path from S to the R's:

If we leave away the parts that don't belong to the Input Module, we are left with

As an abstract model the Input device looks as follows:

One of the outputs (PoPS OUT1) should be high and the other (PoPS OUT2) low when the PoPS IN is high and vice versa when PoPS IN is low.

NOR Module