Active-HDL - Tips, Hints, and Reference

Active-HDL is an industrial-strength design tool.  Like any tool, used in the right way, it is very powerful and productive; but there are certain and quirks and idiosyncrasies which, if ignored, will lead to hours - yea days - of frustration.  This page gives guidelines and tips for using the tools so that you don't run into problems.  They are listed in section in decreasing order of importance.
 If you know something that should be included here, please mail it to us and we will add it. 

Rules to Always Follow:

· Keep it simple and don't stray from straightforward, proven ways of doing things.  Don't expect the tools to do things the way you think they should be done.  Don't fight the tools, go with the flow.  The tools always win.

· Save often; this should be obvious.

· Run Check-Diagram often, at least before you compile. This will point out problems that can cause you hours of frustration.

· Pay attention to warnings. At least understand what they are before you ignore them.

· Compile often. If a design file has been compiled before, Active-HDL will often run with the old version even if the source code has been changed since you last compiled.

· Always choose Verilog whenever Active-HDL asks you to choose a hardware description language. CSE 370 will not use VHDL or any other of Active-HDLs options at any point.

· Always make new designs with design flow. This matters much more later once you are using the FPGA, but get in the habit.

· Make a Local Copy of a file when your add it to a design, unless you really know what you are doing.

Things to Never Do:

· Never start the name of a file with a numeric character (0-9). If you do, you will probably need to replace it with a new file and move the contents. This is a serious problem with Active-HDL.

· Don’t try to rename a file. Instead create a new file and copy the contents over.

· Never name two files the same name, even if one is a Verilog source file and one is a .bde, they will both be compiled into modules with the same name.

· Never use manual input stimulators (for example clock stimulators) and a test fixture to drive inputs at the same time. This will cause very strange and incorrect simulation behavior.

General Troubleshooting:

If Active-HDL is acting strangely and/or you think your design should be working but it isn't, you can try these steps in addition to asking a TA or SLA for help.

1. Make sure you haven't done anything under the "Things to Never Do" section above.

2. Make sure you ran what you thought you did. Check your top-level.

3. Run Check Diagram to ensure that there are no small wiring bugs or other non-obvious problems in your schematic. Active-HDL's schematic editor often makes disconnections in your wiring very difficult to see.

4. Click Compile-All to ensure that your most recent changes were all reflected in the compiled design Active-HDL is running.

5. Right-click the library with the same name as your design and choose Clear Simulation Data. Then Compile-All to reset your compiled design.

6. Save your work and restart Active-HDL. Using an Active-HDL session for more than an hour is asking for trouble.

7. In

Schematic Editor:

· Each schematic has an associated symbol (in the Symbols Toolbox) that you use to make hierarchical schematics.  However, changes to the schematic or to the symbol are not reflected automatically in the other.  Here's what you have to do:  Right-click on your symbol, and select "Compare symbol with contents...".  This will tell you if there has been a change and it will ask you whether you want to change the schematic or the symbol.  Usually you want to change the symbol because of a change you made to the schematic.  Presto, things are fixed.

· You can change the symbol for a component by right-clicking and using the "Edit symbol in separate window" option.  (Don’t use this to fix the above problem.)

· You should always name your busses – Active will often get the right size, but will sometimes make a mistake. This also makes it easier to debug.

· If you cannot compile, or the option to set a module as top level seems to be missing

Check that you are working with the active design. The design that is current active is in boldface in the file-browser tab. To make a design active, right-click it and select Set as Active Design.

· If the probes that show the values of wires in your schematic whenever a simulation is running have gone missing:

Click Diagram->Probes->Add Probes.

· If a schematic (.bde) file name italicized and won't compile, it probably does not have a target language:  

Close the file first (important), then do [Design->Change Target HDL] and choose Verilog.  Ignore the warning.  It may also indicate that the file is not part of the compilation: Right-click on it and [Include in Compilation]. If the schematic editor insists on creating block diagrams with the name italicized, use the Wizard instead to create a file.
(Restarting Active-HDL usually solves this problem.)

· To add wire-stubs to all pins of a symbol quickly, right-click and select "Add-Stubs".

Simulator:

· If you cannot add ports to the waveform:

Make sure that you have initialized a simulation.

· If the waveform does not seem to make sense:

Click Zoom-to-Fit (a button on the waveform viewer toolbar) to zoom out to the entire waveform then zoom in to the desired region.

· Stimulators only work from the waveform window.  To watch the signals in the block diagram while using stimulators, detach the waveform window and position it so that both the waveform and block diagram windows are visible.  Run the simulation from the waveform window using F5 and the stimulators while watching the signals in the block diagram window.

Synthesis:

· If you get:
# Error: Path to Quartus <number> not found. Specify the path to the vendor tool in the Flows -> Integrated Tools category of the Preferences window.

Click Tools->Preferences. In the list on the left, expand Flows under the Environment category. Select Integrated Tools. Make sure HDL Synthesis is set to Altera->Quartus Synthesis and Implementation <number>.

· If synthesis completes successfully but does not generate a .sof file:

Go to the Design Flow tab and click Synthesis & Implementation Options. Go to the Compilation tab and make sure that the 2nd, 4th, and 6th checkboxes (not radio buttons) are checked. The 4th (Run Assembler During Compilation) ensures your .sof is generated.

· (Advanced) If you want more detailed compilation output out of the simulator:

Select GUI rather than Batch for the compilation mode under Synthesis & Implementation Options->Main