What is CASE statement in Verilog?
What is CASE statement in Verilog?
The Verilog Case Statement works exactly the way that a switch statement in C works. Given an input, the statement looks at each possible condition to find one that the input signal satisfies. They are useful to check one input signal against many combinations. This is done via the “default: ” statement.
How do you write a case statement in Verilog?
A Verilog case statement starts with the case keyword and ends with the endcase keyword. The expression within parantheses will be evaluated exactly once and is compared with the list of alternatives in the order they are written and the statements for which the alternative matches the given expression are executed.
Can you do nested if statements in Verilog?
When we omit the else branch in our if statement code then none of the branches will execute in this case. The code associated with each branch can include any valid verilog code, including further if statements. This approach is known as nested if statements.
What is full case and parallel case in Verilog?
A case statement in Verilog is said to be a parallel case when it isn’t possible for multiple case items to be equal in value to the case-expression. The significance of parallel case statements is that case statements that are not parallel infer priority logic during synthesis.
What is case Z?
casez treats all z values in the case alternatives or the case expression as don’t cares. All bit positions with z can also represented by? in that position. casex treats all x and z values in the case item or the case expression as don’t.
What is Verilog Case 1 )?
In Verilog, a case expression can either be a constant, such as “1’b1” (one bit of ‘1’, or “true”), it can be an expression that evaluates to a constant value, or most often it is a bit or vector of bits that are used to compare against case items.
What is the difference between case and if statement in Verilog?
Since if-else infers priority, it should be used when more than one input condition could occur. Using case , one the other hand, is appropriate when the inputs are mutually exclusive. There are also dozens of posts on this subject on Stack Overflow for every conceivable language.
What is synthesizable and non synthesizable in Verilog?
Synthesizable Verilog is that subset of the language that are accepted by the synthesis tools. The non-synthesizable constructs are used only for simulation and the synthesis tool cannot handle them.
How do you write a synthesizable Verilog code?
As I see it, there are three aspects to writing synthesizable Verilog code: the particular features of the language to use, the style and idioms employed in using those features, and the tooling support for a design….The language
- behavioural.
- structural/register-transfer level (RTL)
- gate.
- switch/transistor;
To the Verilog simulator, full_case and parallel_case are buried inside of Verilogcomments and are completely ignored. To the synthesis tool, full_case and parallel_case are command-directives that instruct the synthesis tools to potentially take certain actions orperform certain optimizations that are unknown to the simulator.
When do we use disable statement in Verilog?
The Verilog disable can also be used to break out of or continue a loop, but is more awkward than using break or continue. The disable is also allowed to disable a named block, which does not contain the disable statement. If the block is currently executing, this causes control to jump to the statement immediately after the block.
What is the use of Verilog?
Verilog is a HDL (Hardware Description Language). It is used to model and simulate digital electronic circuits. Once a design is simulated, tested and ready for ‘tape-out’ to the fab, it can be synthesized to produce gate level designs that are then translated to physical design.
