Use this when editing a Part to define the Part as a digital Counter.
Use this on a Counter component in a schematic design to change its parameters, or to replace it with a Counter part using a different number of bits or different reset.
These parts are implemented by using Functional Modelling. They have their Spice Type Built-in Function set to Counter.
Shortcuts
Default Keys: F7
Default Menu: Simulation
Command: Edit Spice Value/Model
How To Add A Counter
There are various ways to add a Counter to a Schematic Design:-
- From the Parts toolbar, click on the Digital Generic pop-up to display the Digital Generic toolbar. Click on the Counter button.
- From the Parts Browser, click on Spice Category, then on Digital and Generic to display the Digital Generic parts. Drag the Counter part name into the design. Note: This method may not work if you have changed the part categories.
- Use Component from the Insert menu to add the Part called Counter from the SPICE library.
Whichever method is used, you should be presented with the Define Counter Dialog described below. This works because the part named “Counter” has a blank function definition which forces the dialog to be given to get the required definition from you.
How To Define A Counter
In a Schematic Design, select the Counter device(s) that you wish to change. Press F7 or use the Edit Spice Value/Model option from the Simulation menu, or from the shortcut menu.
From a Parts Library edit the required Part. Press the Edit Spice button on the Details tab. Make sure the Built-in Function is set to Counter and press the Edit Definition.
In both cases the following dialog will be displayed:
Number Of Bits
Enter the width of the register. Valid values are from 1 to 32.
Maximum Count
Enter the number that the counter counts up to before resetting back to zero. If you check the Use Absolute Maximum Count button the Maximum Count field will be set to the absolute maximum i.e 2 to the power (bits) - 1;
Has Reset
The simulator’s arbitrary logic block function supports the addition of asynchronous controls to synchronous registers. Check this box if the counter has an asynchronous reset.
Clock To Out Delay
Enter the clock to output delay, such that the actual output pins will change state after this delay following the output being assigned.
See the Arbitrary logic block section in the Simulator’s Device Reference Manual for more details and an example of how the counter works.
Changing the Symbol
If editing a Part, make sure the chosen Number Of Bits and Has Reset state match the Symbol that is used by the Part.
If editing a component in a schematic design, pressing OK with changed Number Of Bits or Has Reset state will force the component to be replaced with a Part from the Library that matches the new specification. If no suitable Part exists, an error message will be given giving details of the Part that will need to be created.
Editing Multiple Components
If any of the fields are set to