# What is X and Z in Verilog?

## What is X and Z in Verilog?

Hardware description languages such as SystemVerilog use the symbol ‘X’ to describe any unknown logic value. If a simulator is unable to decide whether a logic value should be a ‘1’, ‘0’, or ‘Z’ for high impedance, it will assign an X.

How do you instantiate memory in Verilog?

To instantiate a RAM or ROM function in Verilog HDL, follow these steps:

1. Use the genmem utility to generate a memory model by typing the following command at the UNIX prompt:
2. Create a Verilog HDL design that instantiates the function.
3. (Optional for RAM functions) Specify an initial memory content file:

### What is the time period of clock #10 clock clock?

If the clock changes each 10 time units, it’s period would be 20 time units e.g clock changes every 10 seconds, it’s half cycle would be 10 seconds and its period would be 20 seconds.

What does timescale 1ns 1ps define?

`timescale 1ns/1ps means that all the delays that follow (like# 5.1234) are interpreted to be in nanoseconds and any fractions will be rounded to the nearest picosecond (5123ps). However, all delays are represented as integers. The simulator knows nothing about seconds or nanoseconds, only unit-less integers.

## What is delay in Verilog?

Verilog Gate Delay. Verilog gate delays specify how values propagate through nets or gates. The gate delay declaration specifies a time needed to propagate a signal change from the gate input to its output. The gate delay declaration can be used in gate instantiations.

What is the result of 1 & Z in Verilog?

The SystemVerilog value set consists of the following four basic values: 0—represents a logic zero or a false condition 1—represents a logic one or a true condition x—represents an unknown logic value z—represents a high-impedance state The values 0 and 1 are logical complements of one another.

### What does Z mean Verilog?

2. 1. Verilog output port is high impedance (Z) when driven by a sub module.

Verilog HDL contains the \$readmemb or \$readmemh system tasks to do the file read if the file data is formatted in a specific way using either binary or hexadecimal data. TestBench is like just an interface between external vector source and DUT. Sometimes outputs are also to written to external files.

\$readmemh is not synthesizeable. It is used for simulation or behavioural code only.

How do I find my clock cycle?

1. CPU clock cycles = Instruction count x CPI.
2. CPU execution time =
3. = CPU clock cycles x Clock cycle.
4. = Instruction count x CPI x Clock cycle.
5. T =
6. I.
7. x CPI x C.

### How do you calculate clock period?

The clock period or cycle time, Tc, is the time between rising edges of a repetitive clock signal. Its reciprocal, fc = 1/Tc, is the clock frequency.

When is no RAM inferred in Verilog design file?

No RAM is inferred for devices without RAM blocks. Similarly, if the Verilog Design File describes an asynchronous RAM, no RAM is inferred when the target family has RAM blocks that do not support an asynchronous mode.

## How many output lines are there in 16×4 memory?

Note1: I know that the 16 X 4 memory contains 4 output lines. there is also a 4-bit input to construct the 16 WORDS. Note2: The problem arises as the RAM 32 X 8 contains 8 output lines and 5-bit input. But i want to use 4 of RAM 16 X 4.

How does Quartus II handle RAM with separate read and write clocks?

When the Quartus II software infers a RAM block for a memory with separate read and write clocks, the functionality of the design will change slightly. The behavior when reading and writing to the same address will be different.