Please note:
The Gnome II introduce 12 new instructions and the ability
to detect pressed Buttons (can also be seen as an example of
good and bad synchronization) -
Find the Gnome II
here
All digital electronic
equipment of our modern world based at the "old" principle of
the Finite State Machine. All action inside controlled by a
single Clock single. (A Finite State Machine also called a
Synchronous State Machine)
The basic SSM
consist of three blocks of logic:
The State Memory
made by one or more D-F/F's (Yes other F/F's types
possible)
The Next State
Logic produces the Next State value (a combination of
0/1 values) which should become the new Current State by
the Next Clock pulse.
The Output Logic
will use the Current State the produce an Output
combination (Moore Output)
If the Output depends on both input values and the
Current State are they name Mealy Outputs.
A more simple way
to produce output will be a technique called "Output
Coded States".
The "Brain" of a CPU
actually a State Machine which works in a number of
states (three in this case) in order to Fetch,
Decode and Execute instructions stored in the
Program Memory.
