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This TechWatch is based on the second part of my Design Reuse with Altium Designer presentation from our user conference on the 31st October 2006. The rest of the topics will be covered in future TechWatch's. The files for this and all of the other TechWatch's in the Design Reuse series can be downloaded here (451kb). In this TechWatch we will be working with files from the 'Snippet and Multi-Channel Design files' folder.

Design Reuse methodologies can be implemented as a number of “layers”

Layer 1: Features that allow fast and “intelligent” cloning of localised circuitry.

Layer 2: Reusing entire schematic sheets and multi-channel design techniques.

Layer 3: Creation of re-usable, pre-verified, core “components” stored in libraries.

Layer 1:

Summary

In Layer 1 we were really talking about quick and easy to use features. We focused on Design Snippets but there are other features such as simply copying and pasting, Smart Paste, Shift to drag and Insert to clone which when used correctly can be very powerful tools. Look out for examples of these in the 'I didn't know you could do that with Altium Designer 6' TechWatch.

Layer 2:

Multi-Channel Design

Here we are looking at slightly larger forms of design reuse involving entire schematic sheets and using concepts such as Multi-Channel Design...

Many designs contain repeat circuitry. Copying & Pasting can be easy but correcting the design or updating at a later date can be a chore. A repeat statement made within a sheet symbol instructs Altium Designer’s compiler to create virtual clones from a single sheet. Any modifications to the components in the design would only need to be made once.

From the Mixer.PrjPcb open the Output Channel.SchDoc. Here we have a simple stereo mixer circuit that has 8 identical input channels and 2 identical output channels. Rather than using Copy & Paste to reproduce these, we use a special repeat statement in Altium Designer to represent one physical sheet logically ‘n’ number of times.

Compiling will create 2 logical sheets, COUT1 and COUT2. This design may have already been compiled if you have completed the Snippet demonstration from Layer 1 but if you haven't then you will need to so using Project ›› Compile PCB Project Mixer.PrjPCB. We will now drill down to the Output Channel schematic so we can see the effect compiling has. The animated image below will also show us.

We will now look at changing the designator from COUT to something shorter. Select Project ›› Project Options ›› Multi-Channel. There are many predefined choices for the designator format in the Component Naming section. It is also possible to create a user defined format. We will do a little bit of both by choosing the Component Channel Alpha option but also add an Underscore. It should look like this $Component_$ChannelAlpha. Recompile the project to see the change. Component C40 in the COUT1 channel, for example, will have changed from C40_COUT1 to C40_A.

Open the Mixer_Placed_COUT2.PcbDoc. The system can automatically create a ‘room’ on the PCB for each repeated channel. Rooms are definable regions on the PCB that provide a convenient way to organise the placement of components. Once you have placed and routed one channel this can be automatically repeated for all other channels. We can see here that the COUT1 channel has been placed so we will now use the Copy Room Formats command to copy it's placement for the COUT2 channel.

Select Design ›› Rooms ›› Copy Room Formats. The cursor will change to a crosshair and the Heads Up Display (HUD) should ask you to 'Choose Source Room'. Click anywhere in the COUT1 room. The HUD will then ask you to 'Choose Destination Room'. Clicking in the empty room for COUT2 will open the Confirm Channel Format Copy dialog. This board is unrouted but as you will see we have the option to copy routed nets if we wish, also bear in mind that this operation can be performed at anytime. Click OK and you should see that both channels are now placed.

Go to the next TechWatch we will be continuing with Layer 2 and looking at Parametric Hierarchical Design. Or return to Layer 1.