How do you assign bits in Verilog?
Verilog assign statement
- Assign Syntax. The assignment syntax starts with the keyword assign followed by the signal name which can be either a single signal or a concatenation of different signal nets.
- Assign reg variables.
- Implicit Continuous Assignment.
- Combinational Logic Design.
What is assign in Verilog?
Assign statements are used to drive values on the net. This concept is realized by the assign statement where any wire or other similar wire (data-types) can be driven continuously with a value. The value can either be a constant or an expression comprising of a group of signals.
How do I assign a wire in Verilog?
Wire is used as combinational logic. You can assign it, e.g. assign a = 1’b1. In this case, the one which holds the value is 1’b1. Reg can be used as either combinational or sequential logic.
How do you do Bitwise operations in Verilog?
Bitwise operators perform a bit wise operation on two operands. They take each bit in one operand and perform the operation with the corresponding bit in the other operand….
| Operator | Description |
|---|---|
| a == b | a equal to b, result may be unknown (logical equality) |
| a != b | a not equal to b, result may be unknown (logical equality) |
What is assignment to vectors in Verilog?
Legal LHS values
| Assignment Type | Left-hand Side |
|---|---|
| Continuous | Net (vector or scalar) Bit-select or part-select of a vector net. Concatenation of bit-selects and part-selects. |
| Procedural Continuous | Variable or net (scalar/vector) Part-select or bit-select of a vector net. |
What is continuous assignment in Verilog?
Continuous assign statements are used to drive values on to wires. For example: assign a = b & c; This is referred to as a continuous assign because the wire on the left-hand side of the assignment operator is continuously driven with the value of the expression on the right hand side.
What is the difference between == and === in SV?
== can be synthesized into a hardware (x-nor gate), but === can’t be synthesized as x is not a valid logic level in digital, it is infact having voltages in between 0 and 1. And z is not itself any logic, it shows disconnection of the circuit.
What is the difference between assign and always in Verilog?
In general the ‘assign’ statements are used to assign values to nets. always blocks deal with assigning values to registers. Assign statements do not allow blocks of code (unless you use functions). always blocks allow expressing of a hardware behavior in an algorithmic way.
What types are assigned within procedures?
Procedural assignments occur within procedures such as always, initial, task and functions and are used to place values onto variables. The variable will hold the value until the next assignment to the same variable.
What is nets in Verilog?
Nets : represent structural connections between components. Nets have values continuously driven on them by the outputs of the devices to which they are connected to. i.e. nets get the output value of their drivers. If a net has no driver, it gets the value of z(high impedance).
How do you use all bits in Verilog?
If there are the characters z and x the result can be a known value….11.3. Reduction Operators.
| Character | Operation performed | Example |
|---|---|---|
| | | Or all bits | |a = 1’b1, |c = 1’bX |
| ~| | Nor all bits | ~|a= 1’b0 |
| ^ | Xor all bits | ^a = 1’b1 |
| ^~ or ~^ | Xnor all bits | ~^a = 1’b0 |