Verilog黄金参考指南：硬件设计入门必备

需积分: 32 155 浏览量更新于2024-07-21 收藏 270KB PDF 举报

"Verilod Golden Rule Reference Guide 是一本针对Verilog硬件描述语言的精华指南，专注于为初学者提供快速入门的知识路径。该手册由DOULOS出版，适合于FPGA、ASIC设计者以及对HDL有兴趣的学习者，旨在帮助读者理解和应用Verilog进行硬件设计。" Verilog是一种广泛使用的硬件描述语言，它允许工程师用类似于编程的语言来描述数字系统的逻辑行为。此参考指南详细介绍了Verilog的核心语法和语义，以及如何将这些概念应用于实际的硬件设计中。尽管它不是IEEE标准Verilog语言参考手册的替代品，但Verilog Golden Reference Guide提供了更简洁、更易消化的要点，便于初学者快速掌握。在Verilog中，语法是定义代码结构的关键部分，包括模块定义、变量声明、操作符和流程控制结构等。例如，模块是Verilog设计的基本单元，它代表了一个独立的硬件实体。变量声明用于定义存储数据的元件，如寄存器和变量。操作符如赋值（<=）、逻辑运算符（&&、||）以及比较运算符（==、!=）等，用于构建复杂的逻辑表达式。流程控制结构如if-else、case和always块则用于控制设计的行为流程。语义则是理解代码如何在硬件上实现的规则。Verilog支持综合，这意味着编写的设计可以被转换为实际的电路。例如，`always`块在特定条件下触发更新，这在逻辑门和触发器等基本电路的建模中非常关键。此外，该指南可能涵盖了合成过程，这是将Verilog代码转化为可实现的FPGA或ASIC芯片布局布线的过程。合成工具会分析Verilog代码，并生成优化的逻辑门级表示，以便于硬件制造。 Verilog Golden Reference Guide不仅包含这些基础，还可能涉及高级主题，如接口设计、参数化模块、任务和函数、时序控制以及接口与IP核的集成等。这些内容对于提升设计者的技能和效率至关重要，使他们能够创建更复杂、高效的数字系统。总而言之，Verilod Golden Rule Reference Guide是一本实用的参考资料，无论对于初次接触Verilog的新人还是需要快速查找关键信息的有经验设计师，都能提供宝贵的指导和帮助。通过学习这本指南，读者将能够更好地理解和应用Verilog，从而在FPGA和ASIC设计领域取得成功。

A statement which conditionally executes at most one branch, depending on

the value of the case expression.

Syntax

CaseKeyword

(

Expression

)

Expression,...

Statement

{Expression may be variable}

Expression,...

Statement

... {Any number of cases}

[default [:]

Statement

] {Need not be at the end}

endcase

CaseKeyword =

{either} case casex casez

Where

See Statement.

Rules

Xs and Zs in a casex statement, and Zs in a casez statement mean “don’t

care”.

One default statement at most may be included. It is executed if no label

expressions match the case expression. (A ‘label’ is an expression or a

comma-separated list of expressions on the left of a colon, or the reserved

word default, which may or may not be followed by a colon.)

Where a label is a comma-separated list of two or more expressions, the label

is matched if the case expression matches any one of the label expressions.

If no label expressions match the case expression and there is no default

statement, the case statement has no effect.

Gotchas!

If more than one statement is to be executed for a particular label, the

statements must be enclosed in a begin-end or fork-join block.

A branch is only executed if the corresponding label is the first one to match

the case expression. Case labels need not be mutually exclusive, so a

Verilog compiler will not report an error where the same label has erroneously

been repeated.

The syntax of a casex or casez statement ends with the reserved word

endcase, not endcasex or endcasez.

An X or Z in the casex expression or a Z in a casez expression is matched

with any value in a case label. This may give confusing simulation results.

Synthesis

Assignments within case statements generally synthesize to multiplexers. If

variables (i.e. registers or nets) are used for case labels, priority encoders

may be synthesized.

Case

Coding standards are divided into two categories. Lexical coding standards,

which control text layout, naming conventions and commenting, are intended

to improve readability and ease of maintenance. Synthesis coding standards,

which control Verilog style, are intended to avoid common synthesis pitfalls

and find synthesis errors early in the design flow.

The following lists of coding standards will need to be modified according to

the choice of tools and personal preferences.

Lexical Coding Standards

Limit the contents of each Verilog source file to one module, and do not split

modules across files.

Source file names should relate to the file contents (e.g. ModuleName.v).

Write only one declaration or statement per line.

Use indentation as shown in the examples.

Be consistent about the case of user defined names (e.g. first letter a capital).

User defined names should be meaningful and informative, although local

names (e.g. loop variables) may be terse.

Write comments to explain (not duplicate) the Verilog code. It is particularly

important to comment interfaces (e.g. module parameters, ports, task and

function arguments).

Use parameters or `define macros wherever possible, instead of directly

embedding literal numbers and strings in declarations and statements.

Synthesis Coding Standards

Partition the design into small functional blocks, and use a behavioural style

for each block. Avoid gate level descriptions except for critical parts of the

design.

Have a well defined clocking strategy, and implement that strategy explicitly in

Verilog (e.g. single clock, multi-phase clocks, gated clocks, multiple clock

domains). Ensure that clock and reset signals in Verilog are clean (i.e. not

generated from combinational logic or unintentionally gated).

Have a well defined (manufacturing) testing strategy, and code up the Verilog

appropriately (e.g. all flipflops resettable, test access from external pins, no

functional redundancy).

Every Verilog always should conform to one of the standard synthesizable

process templates (see

Always

An always describing combinational and latched logic must have all of the

inputs in the event control list at the top of the always.

A combinational always must not contain incomplete assignments, i.e. all

outputs must be assigned for all combinations of input values.

An always describing combinational and latched logic must not contain

feedback, i.e. registers assigned as outputs from the always must not be

read as inputs to the always.

Coding Standards

剩余150页未读，继续阅读

塞北江南之阿华

粉丝: 3
资源: 5

Verilog黄金参考指南：硬件设计入门必备

verilog黄金参考指南中文版.pdf

Verilog-HDL编写规范（全）

超全Verilog培训教材及参考例程

Vhdl_Golden_Reference_Guide.zip_Golden

Vhdl_Golden_Reference_Guide.rar_Golden

Vhdl_Golden_Reference_Guide.rar_Golden_verilog

Vhdl_Golden_Reference_Guide.rar_Golden_vhdl_vhdl 教程

UVM_Golden_Reference_Guide.rar_Golden_Practical UVM_UVM_UVM refe

vhdl_golden_reference_guide_pdf_vhdl_

vhdl_golden_reference_guide_pdf_vhdl_说明.zip

最新资源