How does the sequential circuit use a memory cell in a typical FPGA in this lecture, taking the general
sequential circuit definition?
I'm going to handle this question.
The term sequential means one after another.
Therefore, we expect that operations and tasks are executed one after another in order.
So there should be a mechanism to keep track of the status of the sequence.
Memory elements are an excellent candidate to save the states.
A typical structure of a sequential circuit has two main parts a combination or circuit that performs
the logic of the tasks and the memory part that stores the state execution sequences and transfers data
between these sequences.
As memories in FPGA commonly used flipflops as the building blocks.
A clock signal should determine the time boundary between two sequences of executions and triggers,
saving the states and data generated by the combination of certain.
The combination of circuit in each sequence should use the input data, as well as the data in the memories
to generate outputs and then you memory contents.
The previous diagram is general enough to represent all sequential circuits.
However, this diagram shows more details here.
I have emphasized that the memory part can get some data directly from the design primary inputs and
give some data directly to the design primary outputs.
Let's consider this simple sequel.
Which consists of a single fall, it accepts an end with binary value and generates it's even part of
it.
Default is not unrolled, so it's sequential RTL Circuit should implement the.
This article circuit consists of an X or gate to perform the functionality added flip flop to save the
temporary data, which here is the part it.
Note that the hotel circuit also has some circuits to keep track of Loop Iterations index.
However, for the sake of simplicity, I have ignored that part.
Let's consider one iteration of the loop.
It consists of one logic operation, which is an exercise and a simple assignment.
However, if you look at the operation carefully, it consists of three tasks Rippey from the Flipflop
perform XOL functionality right back.
The result to the different.
Note that in this example, the value is provided by the function input, and we assume that it is available
throughout the whole task.
And we don't need to read that from memory.
A set of wires can implement a variable, please recall the combination also could implementation concepts
presented in the previous course.
And this is like I'm going to demonstrate the sequence of execution of this, Luke.
Later, we use this concept to design a sequential circuit in Etchells, therefore understanding this
simple sequence is essential.
Let's assume that only one clock cycle is required to perform.
The logic operation of the body represented by the Aldgate T denotes the clock period.
Then in the first class period, the design designer initialized party bit saved in a flip flop and
generate the new parity bit and write that into the same degree for the same functionality is performed
in the second cycle and afterwards.
Let's review the same sequence for a general sequential search.
As I mentioned before, this figure models the general sequential circuit, it consists of two main
parts, a combination of circuit and memory cells.
The circuit also receives inputs and the clock signal and generates outputs.
Again, we assume that the combination of circuit performs its task in one clock cycle.
Then this diagram shows the circuit execution sequence in each clock cycle, the combination of circuit
reads the data and state performs its task and write the new state into the memo.
Results will back to this concept later in the next section to get some idea for designing a group of
sequential circuits in Etchells.
The clock signal is essential in sequential seconds as it orchestrates all Dealogic activities in the
design, but what are the signal characteristics in the next lecture?
I will answer this question.
These are the takeaway messages from this lecture, the sequential circuit consists of a combination
of circuit and a set of memories.
Memory cells can store the circuit states or data.
Now, the quiz question, consider this simple C-code show the execution sequences of the code using
the corresponding simplified hardware structure.