Frequently Asked Questions
Repeated blocks of circuitry
[ General / Repetitive Blocks ]
From time to time, designs require the use of repetitive blocks of circuitry - a mixing desk being the classic example. Easy-PC supports this requirement, avoiding the tedious task of laying out multiple iterations of the same pattern. However, it must be stressed that using copy and paste in the schematic and pcb does NOT work, as even if by some chance the component numbering matches, the net names certainly won't!
The process starts with the schematic. Two approaches are possible. Either use a standard piece of circuit, then copy and paste it, or use a standard schematic, save it under different names, then add each iteration to a project. In both cases, before any duplication takes place, one preliminary step is vital. Select all the circuitry required for an iteration, then right click and use [Group]. It is unimportant whether this is a tight group or not, but it is vital that the 'Schematic Only' box is unchecked, as the groups are required in the pcb design. Now when the initial iteration is duplicated, new groups covering the copies will also be created.
When the schematic(s) have been translated to pcb, lay out the pattern for the first iteration. When this has been completed, select all the elements of the pattern which need to be repeated then use Ctrl+C to copy this to the clipboard. Whilst you can just use the group as the sourse, this approach gives you finer control over exactly what will be copied.
Next, go to [Tools], [Apply Layout Pattern]. The <F1> key will bring up the help page relating to this dialogue. Set this up to copy from clipboard to the next group for the second iteration. This will give you a copy of the pattern under your cursor ready for placing, but using the components and nets associated with the secong iteration, not the first. Place this, then repeat the last part for each of the remaining iterations. You may experience difficulty aligning the copy exactly with the grid. If this happens, before you lose the selection, left click and hold (do not release) on an element (usually a pad) known to align with the grid, then use the cursor keys to snap this to the grid, pulling the remaining items into alignment. Once aligned, the mouse may be released.
There are some caveats when using this function. Because the program has to match the pattern using interconnections between component types with specific pin numbers, if the pattern contains similar elements, it's very likely that at some point these will be confused - e.g. if the pattern contains two identically comfigured opamps, for example. If this is likely to be an issue, split the pattern up into two or more parts, each with its own group, and repeat these separately to avoid the problem. The second caveat is that although the function supports repeating the pattern from one group to another, it's generally better to use the clipboard as the source, simply because it gives more control over exactly which elements of the tracking will be included in the pattern.
Using this technique will avoid any unpleasant surprises when using Integrity Check or Forward Design Changes - at least in this area!