| AR# |
24506 |
| Part |
SW-Modelsim XE |
| Last Modified |
2009-06-22 00:00:00.0 |
| Status |
Active |
| Keywords |
HDL, Mentor Graphics, RTL, gate-level, simulation, MXE III, ModelSim PE, MXE III Starter, PE, SE, FAQs |
Description
Keywords: HDL, Mentor Graphics, RTL, gate-level, simulation, MXE III, ModelSim PE, MXE III Starter, PE, SE, FAQs
This Answer Record provides answers to Frequently Asked Questions (FAQ) related to ModelSim Xilinx Edition III.
Solution
Q1. What is MXE III?
MXE III is an HDL simulator used to simulate Xilinx designs. The MXE III simulation engine is based on ModelSim PE, which is available from Mentor Graphics.
Q2. Can MXE III be used to simulate both RTL and gate-level designs?
Yes, MXE III can be used to simulate both RTL and gate-level designs.
Q3. What are the major differences between MXE III and ModelSim PE?
MXE III is the same as ModelSim PE, but with performance and executable line (statement) limits.
Q4. What is MXE III Starter?
MXE III Starter is identical to MXE III, but with tighter performance and line (statement) limits.
One of the biggest limitations is that Xilinx compiled libraries are also included in line count. So MXE starter will not be able to do timing simulation in most cases since the line limit will be reached faster in MXE Starter.
Line count Methodology in MXE
ModelSim XE-starter --counts the instances flat (all instances are counted).
ModelSim XE ---counts the instances hierarchically (each instance type is only counted once), and Xilinx precompiled libraries are not counted.
Q5. Is MXE III supported on PC and UNIX/Linux platforms?
No, MXE III is supported only on Windows XP 32 bit OS.
Q6. What are the performance and line limits for MXE III and MXE III Starter as compared to ModelSim PE?
Performance and Line Limits ComparisonQ7. What is meant by "30% of PE for < 10000 lines"?
The 30% of PE specifies the performance (speed) of the simulation engine. It does not slow down the time needed to compile the design (VCOM/VLOG) or to load the design in MXE III (VSIM). The slowdown occurs during simulation. For example, a design that takes 20 seconds to run in PE, will take approximately 60 seconds to run in MXE III.
Q8. What is the upper threshold of densities that MXE III can simulate without going over the 50,000 line limit?
In most cases, MXE II simulates designs up to 1M system gates without encountering performance degradation after 50,000 lines; however, this is design-dependent. (For example, a 2-bit adder that uses two LUTs and a 64-bit multiplier that uses 6126 LUTs are both considered to be a single line of code.)
Q9. Who can use MXE III most effectively?
Designers who simulate up to 1M system gate designs and do not have problems with potentially running into the line and performance limits.
Q10. Is Toggle Coverage supported by MXE?
No. MXE does not support Toggle Coverage.
Q11. What is a line (statement) or executable line of code?
Only executable lines of code are counted. These are the lines in which a user can set breakpoints, or the lines to which the simulator can "step" while debugging. For example, only six executable lines are counted, even though there are 12 lines that contain semicolons (the line delimiter character):
entity counter is
port (count : buffer bit_vector(8 downto 1);
clk : in bit;
reset : in bit);
end;
architecture only of counter is
constant tpd_reset_to_count : time := 10 ns;
constant tpd_clk_to_count : time := 5 ns;
begin
ctr: process(clk, reset)
begin
if (reset = '1') then
if reset'event then
count <= (others => '0') after tpd_reset_to_count;
end if;
elsif clk'event and (clk = '1') then
count <= increment(count) after tpd_clk_to_count;
end if;
end process;
end only
Q12. Are the testbench and library included in the line count?
The line count includes both testbench and source code lines. The libraries and primitives are also included in this count. Empty lines and comments are NOT included in this count. However, there is a major difference in the way that the library lines are counted. For Xilinx simulation libraries, one instance is counted as one line, rather than counting all of the lines of code in that instance. For example, a VHDL FDC model is counted as one line rather than the 100+ lines of code that describe it.
Q13. Is this line counting feature available for user-compiled libraries?
This favorable method for counting lines is available for only Xilinx-supplied libraries installed with MXE III, or for libraries available at:
http://www.xilinx.com/support/download/index.htmThis feature is not available for user-compiled libraries.
Q14. How do I confirm that a line is an executable line?
To determine whether a line is executable, open the source window in MXE III with a design loaded, and look at the line numbers. Only lines with green line numbers are executable. When you click on the green line number, a breakpoint is set on that line.
Q15. Can MXE III be used to simulate designs that are targeted for non-Xilinx devices?
Behavioral Level - All technology-independent RTL can be simulated in MXE III.
Gate Level (or Behavioral designs with technology-specific instantiations) - MXE III includes Xilinx-compiled libraries. The precompiled libraries count only once per cell. For example, the X_AND2_V component has three executable lines. If the design instantiates 1,000 AND gates, only three lines are counted for the entire design, not 3,000 lines. If you recompile the gate-level libraries manually (a requirement if you are trying to use MXE III for a non-Xilinx design), each instance of each cell counts, so the 1,000 gates are counted as 3,000 lines.
A typical large design can contain a few dozen unique components. Consequently, a manually recompiled library can quickly reach the line limit. Essentially, the simulator is crippled if you try to simulate another vendor's gate-level design in MXE III or try to compile a Xilinx library manually.
Delay Back Annotation - MXE III cannot simulate back-annotated netlists from other vendors because the SDF timing back annotation works for only Xilinx-marked libraries.
Q16. Can I manually compile a Xilinx library in MXE III? Is this recommended?
You should never manually compile the Xilinx simulation libraries. Xilinx does not recommend this for the reasons included in the "Gate Level" section. You should use the precompiled libraries available in MXE III or at:
http://www.xilinx.com/support/download/index.htmQ17. Can MXE III simulate the Xilinx PPC405 and Gigabit I/O SWIFT Models?
No. To simulate SWIFT models, you need a SWIFT-compliant simulator such as ModelSim SE, ModelSim PE, Synopsys VCS, or Cadence IUS.
Q18. What is ModelSim SE?
ModelSim SE is the high-end simulator available from Mentor Graphics.
Q19. What are the major differences between MXE III Starter, MXE III, ModelSim PE, and ModelSim SE?
Differences Between MXE III, Starter, PE, and SEQ20. When should I use ModelSim SE?
Review the differences between ModelSim PE and SE at:
http://www.model.com/products/pdf/datasheets/ModelSimChart.pdfThis comparison can help you to determine which simulator is best suited to your requirements.
Q21. Whom should I contact for technical support questions regarding MXE III or MXE III Starter?
For all questions about MXE III, contact Xilinx Technical Support at:
http://www.xilinx.com/support/support.htmQ22. How much does MXE III Starter cost?
MXE Starter is free and is available as a part of the ISE WebPACK and ISE Foundation products.
Q23. How much does MXE III cost?
MXE III costs approximately $1000 for a 1-year license. For exact pricing on this Development System option, see the Xilinx Online Store at:
http://www.xilinx.com/onlinestore/index.htmQ24. Whom should I contact if I want to purchase MXE III?
Use one of the following options:
- You can buy online at:
http://www.xilinx.com/onlinestore/index.htm- You can contact your local Xilinx sales representative.
Q25. Whom should I contact if I want to purchase ModelSim PE or SE?
Contact your local Mentor Graphics sales representative at:
http://www.mentor.com/region/sales_offices.htmlQ26. Whom should I contact for technical support questions regarding ModelSim PE or SE?
Contact Mentor Graphics Technical Support at:
http://supportnet.mentor.com/
Q27. Where can I find information about licensing options for MXE III?
See
(Xilinx Answer 9859).
Q28. Is Windows Terminal Services supported with MXE?
License checkout for MXE is not supported from clients of Windows Terminal Services.
Q29. Is code coverage supported by MXE?
No. MXE does not support Code coverage.
Q.30. Is floating license supported in MXE?
No. Floating license feature is not available for MXE. For more information on licensing MXE, please refer to
(Xilinx Answer 9859).
Q.31. Does MXE support FLI (foreign language interface)?
No. MXE does not support FLI.
Q.32. Is Verilog PLI supported in MXE?
Yes, PLI is supported in MXE. Each PLI system task is counted as one line just as each line of Verilog code is counted.
Q.33. Is secureIP simulation supported in MXE?
No.
