Design Verification on proteus-7.8
It is always a good idea to spend a little time checking the schematic before we move through to PCB layout. ISIS provides a unique and extremely powerful tool in the form of the Design Explorer that will help us catch any errors before we sign off on the schematic phase of design. In this tutorial we will introduce the tool and cover some basic functionality but we do recommend that you read the section in the reference manual (Help Menu – ISIS Help) and spend some time familiarizing yourself with it’s many capabilities.
Note that what you see in the Design Explorer throughout this section will depend on whether you have drawn the schematic yourself or loaded the pre-supplied one from disk.
The Design Explorer
The Design Explorer is launched from either the Design Menu or using the toolbar icon at the top of the application.
When invoked and in it’s default mode, you should see a dialogue form that looks a little like Windows™ Explorer. The left hand pane displays the sheets and the right hand pane displays the contents of the currently selected sheet. Clicking on another sheet in the left hand pane will force the right hand pane to show the contents of that sheet selected.
The Design Explorer has two distinct modes; partlist mode and netslist mode. The former will show a physical representation of the sheets (the components on a sheet) whilst the latter will show how the design is organized into groups of connections (nets). You can switch between the two modes via the icons at the top left of the window.
Since we are in partslist mode by default let’s look at what we can do from there. You may remember that earlier in this topic we discussed how to check the packaging for a single part. The Design Explorer shows us the bigger picture and allows us to make a global check of the packagings on the design at a glance. All of the footprints used are displayed beside their schematic reference at the far right hand side of the right hand pane so all we need to do is scan down the list to make sure everything is packaged, switch sheets (via the left hand pane) and repeat the process. If a part on the schematic did not have a footprint assigned it would have bright red text in this field to highlight the potential problem.
A quick scan will immediately show that we do not have a packaging associated with the LED schematic part. Right click on the Design Explorer on the line with the LED and select Goto Schematic Part from the context menu.
This will zoom the schematic around the part and tag it for editing. Simply right click on the highlighted part and select Edit Properties in the normal way. We could follow the procedure that we discussed earlier to find a suitable footprint but in this case take it as a given that it is named LED and simply type in LED in the PCB Package field of the dialogue form.
At this point you may get a message to say that the Design Explorer has closed as the schematic has been changed. This is an optional advisory and you can disable it in future by selecting the checkbox on the message box.
The final step is to re-invoke the Design Explorer and verify that all of our components are now correctly packaged. This time we should see no missing packagings but closer examination will reveal that we changed a footprint on one of the resistors earlier on for demonstration purposes – this is not actually what we want for this design. Let’s change it back now to the original surface mount footprint.
First, scan down the list (changing sheets if necessary) until you locate the resistor with the RES40 package.
Now, simply follow the same procedure as above to change the footprint to an 0805.
We can also use the Design Explorer to investigate the connectivity of the schematic – for this we need to switch into netslist mode via the icon at the top left of the dialogue form. This will give us a view as shown below.
The first point to note is the net names which, as we discussed earlier, are either named according to terminal or label or simply assigned a number if the net consists only of wire connections. We can right click on any net to view it’s connections on the current sheet by selecting the ‘Goto Schematic Net’ option from the resulting context menu. This is particularly useful when we want to check single pin nets for example, or if we want to name a net manually (see the section on connectivity considerations earlier in the tutorial). Finally, where we have a net or nets grouped with a named net class (far right column on the right hand pane) it can be useful to check our assignments.
The Design Explorer is an extremely powerful tool and has many different uses throughout the lifecycle of a typical project. In particular it can be used as a link between the schematic and the PCB, facilitating cross-probing and PCB lookup. We recommend that you read and work through the chapter in the reference manual (Help Menu – ISIS Help) for more information.
#collected from the proteus>>help>> tutorial page