SEQUENTIAL
CIRCUITS
FLIP-FLOPS
, Combinational circuits
Combinational
Inputs circuit Outputs
So far we’ve just worked with combinational
circuits, where applying the same inputs always
produces the same outputs.
This corresponds to a mathematical function,
where every input has a single, unique output.
, Sequential circuits
Inputs Combinational Outputs
circuit
Memory
In contrast, the outputs of a sequential circuit
depend on not only the inputs, but also the state,
or the current contents of some memory.
The same inputs can yield different outputs,
depending on what’s stored in memory.
The memory contents can also change as the
circuit runs.
We need some new techniques for analyzing and
designing sequential circuits.
, What exactly is memory?
A memory should have at least three
properties.
1. It should be able to hold a value.
2. You should be able to read the value
that was saved.
3. You should be able to change the value
that’s saved.
CIRCUITS
FLIP-FLOPS
, Combinational circuits
Combinational
Inputs circuit Outputs
So far we’ve just worked with combinational
circuits, where applying the same inputs always
produces the same outputs.
This corresponds to a mathematical function,
where every input has a single, unique output.
, Sequential circuits
Inputs Combinational Outputs
circuit
Memory
In contrast, the outputs of a sequential circuit
depend on not only the inputs, but also the state,
or the current contents of some memory.
The same inputs can yield different outputs,
depending on what’s stored in memory.
The memory contents can also change as the
circuit runs.
We need some new techniques for analyzing and
designing sequential circuits.
, What exactly is memory?
A memory should have at least three
properties.
1. It should be able to hold a value.
2. You should be able to read the value
that was saved.
3. You should be able to change the value
that’s saved.
