Expert VHDL Design
RTL Synthesis and Synchronisation
Synthesis of Combinational Logic • Synthesis of Sequential Logic • Combinational and Sequential Together • Variables in Clocked Processes • How Many Registers? • Resolution Functions and Drivers • Unresolved Types • Synchronous Design • Synchronous Design Rules • Non-Synchronous Features • How Clever is Your Synthesis Tool? • Resource Sharing • Synthesizing Arithmetic - WYSIWYG • Eliminating the Mux • Shift Left/Right • Forcing an Implementation • Synthesis Attributes • Inference or Instantiation? • Static Timing Analysis • Timing Analysis Exceptions • Re-timing and Pipelining • Timing Analysis Exceptions • Hierarchy and Optimization • Registered Ports • Asynchronous Inputs • Input Hazard • • Metastability • Synchronizer in VHDL • Multiple Clock Domains • Transferring Data Between Clock Domains • Using a FIFO for Synchronisation • Synchronising Reset
Writing Readable Designs
VHDL Features for Abstraction • Record Types • Using Record Fields • Aggregates • Using Records for Wiring • Connecting Records • Inside a Peripheral • Multiplexed Bus Structure • Multiplexing Records • Representing Register Maps • Accessing Individual Registers • Accessing the Status Register • Collecting Registers Together • Alias • Using Aliases with Vectors • Using Alias with a Bus • Other Uses of Alias • Named Ranges • Using Named Ranges • Summary
Writing For Re-Use
Language-Level Reuse • Reusing Code Fragments • Standard Component Reuse • Procuring IP • Writing Reusable RTL IP • Reuse Tradeoffs • Example of a Regular Structure • Arrays of Arrays • Generics • Type Generics • Array Attributes • Generate Statement • More on Generate Statements • VHDL-2008 Generate Statements • Implementing the Behavior • Unconstrained Array Ports • Parameterizing the Data Width • VHDL-2008 Arrays • Multidimensional Arrays • Flattening Matrices • Multidimensional Arrays of Ports • Getting and Setting Rows • Architecture Using 2D Arrays • Instancing The Design • Optional Ports • Default On Component
Advanced Coding Styles
Subprograms • Procedures • Parameter Class, Mode, and Type • Subprogram Overloading • Signal Parameters • Synthesizing Procedures • Destructive Register Reads • Read Procedure • Procedure in FSM • Functions • Recursion • Recursive Function Example • Creating a Generic Counter • Creating a log2 Circuit • Recursive Instantiation • Recursive Component Declaration • Solving the Problem • Solving the Problem (VHDL-2008) • Synthesis Results
Finite State Machine Synthesis
State Transition Diagrams • Finite State Machines • A Simple Two Process Style • Another Two Process Style • One Process Style • State Machine Architecture • Comparison of Coding Styles • Easier Registered Outputs • Registered Outputs Using Local Variables • State Encoding • No Output Decoding • Unreachable States • Controlling Unreachable States • Explicit One Hot Style • Hand Optimised One Hot Style • Collision Signal • Too Many States? • FSM Summary
Packages and Configurations
Packages • Subprograms in Packages • Deferred Constants • VHDL-2008 Packages • Generics on a Package • Float Package • Fixed Package • Fixed Point Example • Use Clause Scope • Component Declaration and Instantiation • Component Declarations in a Package • Configuration • Default Binding Rules • Hierarchical Configurations • Nested Configurations • Port Name Changes • Type Conversions • Setting Generics • Configurations with Generate Statements
Properties and Assertions
Property versus Assertion • Applying Properties • Who Writes Properties? • Observability • A Simple Assertion • Simulation Checker or Monitor • Properties and the Specification • The Story So Far... • OVL • Using OVL with VHDL • OVL Packages • OVL Configuration • Instancing an Assertion • OVL VHDL Assertions • Example Assertions • PSL • The Elements of a Property • PSL Basics • The Structure of PSL • The Boolean Layer • Clocks and Default Clocks • Holds and Implication • next • The Temporal Layer • The Verification Layer • Verification Units • Modelling Layer • Using PSL with an HDL • Simulation of Temporal Properties • Summary of Benefits
Expert VHDL Verification
Functional Verification Methodology
What Is Verification? • Approaches to Verification • Verification Strategy • What to Verify? • Towards a Verification Plan • Don't Plan Everything • Identify Testcases • Verification Metrics • Coverage • Including Functional Coverage • Coverage Driven Verification • From Features to Tests • Checking • Verification Planning Revisited • The Basic Testbench • Verification Environment • Verification Methodologies • VHDL Methodology • Design for Verification • Glass Box Testing • Analysis to Choose Tests • Boundary Conditions & Corner Cases • Black Box Testing • Regression Testing • Stress Testing • Different Sorts of Stimulus
Subprograms and Protected Types
Using Abstraction in a Testbench • Subprograms • Procedures • Parameter Class, Mode, and Type • Subprogram Overloading • Signal Parameters • Functions • Subprograms in Packages • Impure functions • Protected types • Protected type body • Declaring a Shared Variable
More on File IO
The Basic Testbench • TEXTIO Output • Procedure READ • When READ Goes Wrong • Converting Values to Text Strings • Opening and Closing Files • Testing the File Open Status • Managing Text Files • Package STD_LOGIC_TEXTIO • Using Built-in Files • Reading Variable Length Data • Files Without Textio • Binary Files • VHDL-2008 File IO
Transaction Level Verification
Structuring Testbenches • Build the Complete Testbench • Monolithic Testbenches are Inflexible • Hide DUT Interface from Testcase • Layered Architecture • Transaction Level Testcase • Making a Transaction in VHDL • Accessing the Fields • Communicating Transactions • A Simple Example • What is a (VHDL) Transaction? • Interfacing Without Events • Generating Transactions • Using Procedures with Signals • A Systematic Approach • Non-blocking Procedures • Bus Functional Modelling • Bus Functional Model • Bus Functional Model Using Get • Synchronization • Synchronization Channel • Summary
More on BFMs - Time in Testbenches
Bus Functional Modelling • Wait Statements • Wait Statements and Time • Inspecting the Event Queue • Example SRAM Timing • Setup Time Check • Hold Time Check • Combined Setup / Hold Time Check • Pulse Width Check • Entity Declarations • Passive Processes • Using Vital Packages • Setup/Hold Check With Vital • What About Transactions? • Concurrent Signal Assignments • Drivers • How to "See" Drivers • Multiple Driver Issues • Longest Static Prefix • Sequential Signal Assignments • Inertial Delay • Identical Successive Assignments • Inertial Delays • Inertial and Transport Delays • Sampling Data - RTL • Postponed Processes
Behavioral Modelling and Checkers
Checking Results • Variable Latency • Arrays of Records • Queues • VHDL Queue Implementation • Using Queues • Coping with Out-of-Order Completion • Scoreboarding • Dynamic Memory Allocation • Access Types • Allocators • Deallocating Memory • Writing to a FIFO • Reading from a FIFO • Pointer Problems • Behavioural Modelling Example • Modelling the 2-wire Bus • Two Wire Slave Model • Protocol Implementation • Data Generation • Slave Procedure • Modelling State
Random Testing and Coverage
Verification - Reminder • Random Stimulus • Constraining Random Stimulus • Random Sequence of Valid Actions • Functional Coverage • Where Am I? • Concurrent Procedures • Coverage Procedure • Calling Coverage Procedures • Why Use Path Parameter?
Other Testbench Features
Completing our Methodology • Monitoring Internal Signals • Monitoring Internal Signals - VHDL-2002 • External Names • Monitoring Internal Signals - VHDL-2008 • Force and Release • The Objection Mechanism • Implementing Objection • Resolution Functions • Implementing Custom Objections • The Stop and Finish Procedures • Run-time Configuration • Implementing Run-time Configuration
Introduction to OSVVM
What is OSSVVM? • Randomization • Seed Management • Functional Coverage • Sampling • Specifying Bins • Specifying a Minimum Hit Count Per-Bin • Specifying Cross Bins • Specifying Ignore Bins • Displaying Coverage • Non-Repeating Randomize • Defining Explicit Weights • Weight by Coverage Shortfall • Logging • Redirecting to a Log File • Alerts • Stop Count • Disabling Alerts • Conditional Alerts • Hierarchical Alerts • Other Packages
Introduction to UVVM
What is UVVM? • Utility Library • Logging and Verbosity Control • Outputting Log Messages • Controlling Log Messages • Message IDs • Redirecting Log Messages • Alerts • Controlling Alerts • Reporting Alerts • Checks • Awaits • String Handling • Randomization • Signal Generators • Synchronization • BFM Common Package • Warnings • UVVM VVC Framework • UVVM Structure • UVVM Test Harness • UVVM Test Bench • Test Sequencer • UVVM Command Distribution • Example Command Distribution Methods • UVVM VHDL Network Model • VIP • Feature Comparison
