Verification Academy

Search form

My Account Menu

  • Register
  • Log In
  • Topics
  • Courses
  • Forums
  • Patterns Library
  • Cookbooks
  • Events
  • More
  • All Topics
    The Verification Academy offers users multiple entry points to find the information they need. One of these entry points is through Topic collections. These topics are industry standards that all design and verification engineers should recognize. While we continue to add new topics, users are encourage to further refine collection information to meet their specific interests.
    • Languages & Standards

      • Portable Test and Stimulus
      • Functional Safety
      • Design & Verification Languages
    • Methodologies

      • UVM - Universal Verification Methodology
      • UVM Framework
      • UVM Connect
      • FPGA Verification
      • Coverage
    • Techniques & Tools

      • Verification IQ
      • Verification IP
      • Static-Based Techniques
      • Simulation-Based Techniques
      • Planning, Measurement, and Analysis
      • Formal-Based Techniques
      • Debug
      • Acceleration
  • All Courses
    The Verification Academy is organized into a collection of free online courses, focusing on various key aspects of advanced functional verification. Each course consists of multiple sessions—allowing the participant to pick and choose specific topics of interest, as well as revisit any specific topics for future reference. After completing a specific course, the participant should be armed with enough knowledge to then understand the necessary steps required for maturing their own organization’s skills and infrastructure on the specific topic of interest. The Verification Academy will provide you with a unique opportunity to develop an understanding of how to mature your organization’s processes so that you can then reap the benefits that advanced functional verification offers.
    • Universal Verification Methodology (UVM)

      • Introduction to UVM
      • UVM Basics
      • Advanced UVM
      • UVM Connect
      • UVM Debug
      • UVMF - One Bite at a Time
    • Featured Courses

      • Introduction to ISO 26262
      • Introduction to DO-254
      • Clock-Domain Crossing Verification
      • Portable Stimulus Basics
      • Power Aware CDC Verification
      • Power Aware Verification
      • SystemVerilog OOP for UVM Verification
    • Additional Courses

      • Assertion-Based Verification
      • An Introduction to Unit Testing with SVUnit
      • Evolving FPGA Verification Capabilities
      • Metrics in SoC Verification
      • SystemVerilog Testbench Acceleration
      • Testbench Co-Emulation: SystemC & TLM-2.0
      • Verification Planning and Management
      • VHDL-2008 Why It Matters
    • Formal-Based Techniques

      • Formal Assertion-Based Verification
      • Formal-Based Technology: Automatic Formal Solutions
      • Formal Coverage
      • Getting Started with Formal-Based Technology
      • Handling Inconclusive Assertions in Formal Verification
      • Sequential Logic Equivalence Checking
    • Analog/Mixed Signal

      • AMS Design Configuration Schemes
      • Improve AMS Verification Performance
      • Improve AMS Verification Quality
  • All Forum Topics
    The Verification Community is eager to answer your UVM, SystemVerilog and Coverage related questions. We encourage you to take an active role in the Forums by answering and commenting to any questions that you are able to.
    • UVM Forum

      • Active Questions
      • Solutions
      • Replies
      • No Replies
      • Search
      • UVM Forum
    • SystemVerilog Forum

      • Active Questions
      • Solutions
      • Replies
      • No Replies
      • Search
      • SystemVerilog Forum
    • Coverage Forum

      • Active Questions
      • Solutions
      • Replies
      • No Replies
      • Search
      • Coverage Forum
    • Additional Forums

      • Announcements
      • Downloads
      • OVM Forum
  • Patterns Library
    The Verification Academy Patterns Library contains a collection of solutions to many of today's verification problems. The patterns contained in the library span across the entire domain of verification (i.e., from specification to methodology to implementation—and across multiple verification engines such as formal, simulation, and emulation).
    • Implementation Patterns

      • Environment Patterns
      • Stimulus Patterns
      • Analysis Patterns
      • All Implementation Patterns
    • Specification Patterns

      • Occurrence Property Patterns
      • Order Property Patterns
      • All Specification Patterns
    • Pattern Resources

      • Start Here - Patterns Library Overview
      • Whitepaper - Taking Reuse to the Next Level
      • Verification Horizons - The Verification Academy Patterns Library
      • Contribute a Pattern to the Library
  • All Cookbooks
    Find all the methodology you need in this comprehensive and vast collection. The UVM and Coverage Cookbooks contain dozens of informative, executable articles covering all aspects of UVM and Coverage.
    • UVM Cookbook

      • UVM Basics
      • Testbench Architecture
      • DUT-Testbench Connections
      • Configuring a Test Environment
      • Analysis Components & Techniques
      • End Of Test Mechanisms
      • Sequences
      • The UVM Messaging System
      • Other Stimulus Techniques
      • Register Abstraction Layer
      • Testbench Acceleration through Co-Emulation
      • Debug of SV and UVM
      • UVM Connect - SV-SystemC interoperability
      • UVM Versions and Compatibility
      • UVM Cookbook
    • Coding Guidelines & Deployment

      • Code Examples
      • UVM Verification Component
      • Package/Organization
      • Questa/Compiling UVM
      • SystemVerilog Guidelines
      • SystemVerilog Performance Guidelines
      • UVM Guidelines
      • UVM Performance Guidelines
    • Coverage Cookbook

      • Introduction
      • What is Coverage?
      • Kinds of Coverage
      • Specification to Testplan
      • Testplan to Functional Coverage
      • Bus Protocol Coverage
      • Block Level Coverage
      • Datapath Coverage
      • SoC Coverage Example
      • Requirements Writing Guidelines
      • Coverage Cookbook
  • All Events
    No one argues that the challenges of verification are growing exponentially. What is needed to meet these challenges are tools, methodologies and processes that can help you transform your verification environment. These recorded seminars from Verification Academy trainers and users provide examples for adoption of new technologies and how to evolve your verification process.
    • Featured & On-Demand

      • Exploring Formal Coverage
      • Processor Customization
      • Interconnect Formal
      • Formal and the Next Normal
      • Formal Verification Made Easy
      • Data Independence and Non-Determinism
      • Exhaustive Scoreboarding
      • Visualizer Debug Environment
      • Webinar Calendar
    • On-Demand Library

      • SystemVerilog Assertions
      • Practical Flows for Continuous Integration
      • Continuous Integration
      • Questa Verification IQ
      • Avery & Siemens VIP
      • Protocol and Memory Interface Verification
      • HPC Protocols & Memories
      • Preparing for PCIe 6.0: Parts I & II
      • High Defect Coverage
      • SoC Design & Functional Safety Flow
      • Complex Safety Architectures
      • All On-Demand Recordings
    • Recording Archive

      • Lint vs Formal AutoCheck
      • FPGA Design Challenges
      • Design Solutions as a Sleep Aid
      • Fix FPGA Failures Faster
      • CDC and RDC Assist
      • The Dog ate my RTL
      • Questa Lint & CDC
      • Hierarchical CDC+RDC
      • Improving Initial RTL Quality
      • CDC Philosophy
      • Hardware Emulation Productivity
      • The Three Pillars of Intent-Focused Insight
      • All Webinar Topics
    • Conferences & WRG

      • 2022 Functional Verification Study
      • Improving Your SystemVerilog & UVM Skills
      • Automotive Functional Safety Forum
      • Aerospace & Defense Tech Day
      • Siemens EDA Functional Verification
      • Industry Data & Surveys
      • DVCon 2023
      • DVCon 2022
      • DVCon 2021
      • Osmosis 2022
      • All Conferences
    • Siemens EDA Learning Center

      • EDA Xcelerator Academy(Learning Services) Verification Training, Badging and Certification
      • View all Xcelerator Academy classes
  • About Verification Academy
    The Verification Academy will provide you with a unique opportunity to develop an understanding of how to mature your organization's processes so that you can then reap the benefits that advanced functional verification offers.
    • Blog & News

      • Verification IQ
      • Verification Horizons Blog
      • Technical Resources
    • Verification Horizons Publication

      • Verification Horizons - July 2023
      • Verification Horizons - March 2023
      • Verification Horizons - December 2022
      • Issue Archive
    • About Us

      • Verification Academy Overview
      • Subject Matter Experts
      • Academy News
      • Contact Us
    • Training

      • Learning @OneGlance (PDF)
      • SystemVerilog & UVM Classes
      • Siemens EDA Classes
Ask a Question
SystemVerilog
  • Home
  • Forums
  • SystemVerilog
  • $monitor does not get printed

$monitor does not get printed

SystemVerilog 6741
#printstatements 1
natasv
natasv
Full Access
31 posts
August 01, 2022 at 5:54 pm

class display;
int cc, ccmon;
task chkincr( int bbb, int bb);
  for(int ii=0; ii<3; ii++) begin
  #1ns;
	cc = bb+ii;	//increments but does not assign
	ccmon= bb+1;	//increments but does not assign
	$display("\n=============================================================");
	$display("At %0tns display\t: %0d",$time, cc);
	$write("At %0tns No new line: write\t: %0d",$time, cc);
	$monitor("At %0tns monitor\t: %0d",$time, cc);
	$strobe("At %0tns strobe\t: %0d",$time, cc);
	$monitor("At %0tns ccmon monitor\t: %0d",$time, ccmon);
  end
	$display("\n\n|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||");
	$write("\n\tOutside for loop - new line: At %0tns write\t: %0d\n",$time, cc);
	$strobe("\tOutside for loop - At %0tns strobe\t: %0d",$time, cc);
endtask
endclass
 
module top();
int a=10, bbbb=0;
initial begin
	display inca_ii;
	inca_ii = new();
	inca_ii.chkincr(bbbb, a); // pass 10 and 0 respectively
end
endmodule

Result:
/*
=============================================================
At 1ns display : 10
At 1ns No new line: write : 10At 1ns strobe : 10
At 1ns ccmon monitor : 11

=============================================================
At 2ns display : 11
At 2ns No new line: write : 11At 2ns strobe : 11
At 2ns ccmon monitor : 11

=============================================================
At 3ns display : 12
At 3ns No new line: write : 12

|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

Outside for loop - new line: At 3ns write : 12
At 3ns strobe : 12
Outside for loop - At 3ns strobe : 12
At 3ns ccmon monitor : 11
*/

How come "$monitor("At %0tns monitor\t: %0d",$time, cc);" this $monitor statement never gets executed?
The result only shows the ccmon monitor statement from the program, not the other one.

Replies

Log In to Reply
UVM_Xplorer
UVM_Xplorer
Full Access
13 posts
August 01, 2022 at 6:30 pm

In reply to natasv:

Hi,

the reason is that "only one monitoring list can be active at a time. If there is more than one $monitor statement in your simulation, the last $monitor statement will be the active statement."

natasv
natasv
Full Access
31 posts
August 01, 2022 at 10:33 pm

In reply to UVM_Xplorer:

Is this the IEEE standard

dave_59
dave_59
Forum Moderator
11269 posts
August 02, 2022 at 9:18 am

In reply to natasv:

Section 21.2.3 Continuous monitoring wrote:
Only one $monitor display list can be active at any one time; however, a new $monitor task with a new display list can be issued any number of times during simulation.

$monitor is meant to be just a quick and simple debugging statement.

— Dave Rich, Verification Architect, Siemens EDA

natasv
natasv
Full Access
31 posts
August 02, 2022 at 10:47 am

In reply to dave_59:

Thank you.
Sorry, I have another follow on question on $monitor

class display;
int cc, ccmon;
task chkincr( int bbb, int bb);
  ccmon= bb+1;	
 
  for(int ii=0; ii<4; ii++) begin
  #1ns;
	cc = bb+ii;	
 
	$monitor("At %0tns ccmon monitor\t: %0d",$time, ccmon);
	//$monitor("At %0tns monitor\t: %0d ",$time, cc);		 
  end
	$monitor("Outside for loop - At %0tns ccmon monitor\t: %0d",$time, ccmon);	
endtask
endclass
 
module top();
int a=10, bbbb=0;
initial begin
	display inca_ii;
	inca_ii = new();
	inca_ii.chkincr(bbbb, a); // pass 10 and 0 respectively
end
endmodule
 
/*
Result
At 1ns ccmon monitor	: 11
At 2ns ccmon monitor	: 11
At 3ns ccmon monitor	: 11
Outside for loop - At 4ns ccmon monitor	: 11
*/

$monitor description says it prints value at the end of timestamp if there is a change in value of any variable.
How come this program prints "ccmon monitor" at end of every time step, although there is NO change in value of the variable "ccmon" at every time step?
I expected it to print only once at 1ns.

Thanks again.

Solution

Solution

dave_59
dave_59
Forum Moderator
11269 posts
August 02, 2022 at 1:39 pm

In reply to natasv:

It also prints once at the call time to the $monitor statement to establish the initial set of values at the beginning of the monitoring session.

— Dave Rich, Verification Architect, Siemens EDA

natasv
natasv
Full Access
31 posts
August 02, 2022 at 4:45 pm

In reply to dave_59:

Thank you, Dave.

Siemens Digital Industries Software

Siemens Digital Industries Software

#TodayMeetsTomorrow

Portfolio

  • Cloud
  • Mendix
  • Electronic Design Automation
  • MindSphere
  • Design, Manufacturing and PLM Software
  • View all Portfolio

Explore

  • Community
  • Blog
  • Online Store

Siemens

  • About Us
  • Careers
  • Events
  • News and Press
  • Customer Stories
  • Partners
  • Trust Center

Contact

  • VA - Contact Us
  • PLM - Contact Us
  • EDA - Contact Us
  • Worldwide Offices
  • Support Center
  • Give us Feedback
© Siemens 2023
Terms of Use Privacy Statement Cookie Statement DMCA