Data Sheet

PCB Layout
123
Setting up a Design Rule Room
Now that we have the room set up we need to change the design rules inside it. Go back to the
design rule manager and find the room definition. You'll notice when you select the room in the
tree that the right hand side shows you that the default rule but shaded in a light grey. This
indicates that the default rule applies in the area but was defined at a higher level. In other
words, the room inherits the clearances from the board unless you give it specific clearances.
We do this by clicking on the new button to create a new rule, give the rule a name and scope it
to apply to the room and finally setting the clearances we want. In our case we simply want to
turn off the edge clearance test in this area - everything else can stay the same.
Setting a new Rule for the Design Room.
Design Rooms are a really useful concept and helpful wherever clearances vary in
specific regions of the PCB. This can be as simple as pad-pad clearance on fine
pitch SMD devices, fanout areas from BGA's, edge connectors at the board edge
and so on. We strongly recommend you read up further in the reference manual.