Answers Database

Foundation Simulator: How to assign a value to a bus using Formulas


Record #1623

Product Family:  Software

Product Line:  Aldec

Problem Title:
Foundation Simulator:  How to assign a value to a bus using Formulas


Problem Description:
To assign a value to a bus in the Foundation Simulator, you
may apply a Formula to the bus.

The value you wish to assign should be placed in brackets, []
and the value is in Hex.  If you specify a value of [4], and
assign is to an 8-bit bus, the upper 4 bits of the bus will
be driven to 0.

Up to 16 Formulas can be defined as "Formula LEDs".  These
formulas are accessed through the Stimulator Selection
Window.  Formula LEDs are always applied starting at time
0ns.

Additional Formulas can be defined in the Formula Editor, and
are accessed through the Formula Insert and Formula Replace
dialogs.  These Formulas can be applied to the bus starting
at any simulation time, and can be concatenated to create
longer Formulas.


Solution 1:

To define a Formula LED and assign it to a bus, follow this
procedure:

1. Open up the Stimulator Selection Window (Stimulator->
   Add Stimulators).

2. Click on the Formula... button.

3. Select a Stimulator by double-clicking on it.  It will
   now show the Selected Stimulator in the upper-right field.

4. Enter the formula in the Formula field.

   For example, to assign a constant value of 4, the
   following Formula would be used:
	 [4]

   To assign incrementing values to the bus, which increment
   every 20ns, use this formula:
	 [1]20[2]20[3]20

   For more information on proper Formula syntax, please
   refer to the Foundation Online Documentation.

5. After you have typed in the Formula, click 'Assign
   Formula'.  The Formula will now show up in the 'Defined
   Assignments' list.

6. Now, to assign this formula to the bus, select the Bus in
   the Waveform Viewer, and then click on the appropriate
   Form button in the Stimulator Selection box.  For example,
   if you assigned the Formula as Stimulator F1, then click
   on the 2nd square from the right on the Form: line in the
   Stimulator Selection box.



Solution 2:

To define a Formula and assign it to a bus using the Formula Editor, follow this
 procedure:

1. Select Waveform -> Formula -> Edit.	This opens the
   Formula Editor.

2. Enter the formula in the 'Enter New Formula' field.

   For example, to assign a constant value of 4, the
   following Formula would be used:
	 [4]

   To assign incrementing values to the bus, which increment
   every 20ns, use this formula:
	 [1]20[2]20[3]20

   For more information on proper Formula syntax, please
   refer to the Foundation Online Documentation.

3. After you have typed in the Formula, click Add.  The
   Formula will now show up in the 'Available Formulas' list.

4. To assign this Formula to a bus, click in the Waveform
   Viewer to specify both the bus and the time you want the
   Formula to apply to.  Then select Waveform -> Formula ->
   Insert.  Select the Formula and click OK.

5. To concatenate Formulas, click in the Waveform Viewer at
   the end of the first Formula and insert another formula.

   For example, to repeat the incrementing Formula shown
   above, first click in the Waveform Viewer at time 0ns
   (next to the bus you want to assign the Formula to).
   Insert the Formula, which defines the bus from time 0ns up
   to time 60ns.

   Now click on the end of the Formula and insert the same
   Formula again.  Now the bus increments from 1 to 3, then
   repeats.



End of Record #1623