To facilitate manipulation of the various parts of the drawing, there is a cursor selection toolbar in the upper left corner of the program window. (Note that you can t uncheck the current active layer.) EE 333 PCB intro 8ĩ Because there are so many different items in the drawing window, selecting specific items can be tricky. (Note that it takes 3 clicks to cycle through the check marks.) Also, turn on and off the solder mask layers to see those areas. Then turn off and on some of the layers by clicking on the check marks and observe the changes in layout window. Change the active layer to one of the unused layers (Paste Mask Top or something) by double clicking. The active layer indicates where editing actions take place. The toolbox allows us to select which layers are visible and which layer is currently active. EE 333 PCB intro 7Ĩ The design toolbox, on the left side of the UB window, lists all these layers (and more). The ratsnest is not included, but there will be an extra layer for the drill holes that will added to the above list. The layers above are the essential definition of the board that will be sent to the board manufacturer. For simple two-layer boards which almost everyone in EE 333 will be doing the main layers we need to consider are: Copper Top traces on top of the board Copper Bottom traces on the bottom of the board Solder Mask Top contact openings in the topside solder mask layer Solder Mask Bottom openings in the bottom side solder mask Silkscreen Top labels, lettering, and artwork on the topside Silkscreen Bottom same thing but on the bottom Board Outline outer perimeter of the board Ratsnest the initial tangle of interconnects that are converted to traces Board with more trace layers (4, 6, 8, etc) will have correspondingly more layers. EE 333 PCB intro 6ħ As we discussed earlier and as you saw in the PCB videos (You watched those, right? right?!), there are a number of layers involved in defining the complete board layout. (This is the positive power supply connection.) Some of this info may be useful as we proceed. For instance, if we zoom in (use the mouse scroll wheel and window scroll bars) on pin 4 of the op amp, we find some information about it pin number, inner ring diameter, and the node (net) connection. Some info is simply too small to see at a zoomed out scale. Some of it is invisible at the moment we will be able to make it visible when needed. 6 However, there is considerably more information about the layout than what we see here.