In previous tutorials, we learned about associating footprints and components. The next step is to generate Net List. A net list is a description of the connectivity of an electronic circuit. A single net list is effectively a collection of several related lists. It contains all components and their connections. So, by using Net List, we can reconstruct schematic.
Save generated Net List with selected name (we have to remember this file). Now click on the PCB new icon . PCB editor window will appear, that looks like the figure given below.
Fig. 1: Screenshot of PCB Editor Window
In top toolbar and left & right toolbars, there are many useful icons to edit PCB. From these, most important icons are explained in the following table:
|1||Read Net List||This is Net List operations icon; by using this icon we can select, Read, Test and compile Net List.|
|2||Highlight Net||We can highlight any specific track or pad using this option. It is very helpful, in complex PCBs|
|3||Display local ratsnet||When we are connecting tracks from one pad to another, this option will help to detect related connection with the current pad.|
|4||Add tracks and vias||To place vias and tracks we have to select this option.|
|5||Add filled zone||After placing polygon edges to fill the copper plane we will use this option.|
|6||Add graphic line (polygon)||This is very useful and important tool, we can decide the area of the PCB by placing this graphic line and it will help in filling copper on layers also.|
|7||Hide Grid||Sometimes Grid is very important to place components and tracks while sometimes it’s not. So, this option will allow us to show/hide the grid.|
|8||Change cursor shape||When we are placing Edge lines of the PCB and components, the normal cursor is not enough. We need to compare neighbor components and lines; in this case, this option is very helpful.|
|9||Hide board ratsnet||Display general rats nest (incomplete connections between footprints).|
|10||Hide footprint ratsnet||Display footprint rats nest dynamically as it is moved.|
|11||Show filled areas in zones||When we are editing PCB, in some cases, we need to hide the filled copper planes. To show the copper planes, this option can be selected.|
|12||Do not show filled areas in zones||To hide filled zone.|
|13||Mode footprint||Footprint mode: When active, this enables footprint options in the pop-up window.|
|14||Mode track||Routing mode: When active, this enables routing options in the pop-up window.|
|15||DRC||Design Rule check is an automatic check of track connections.|
|16||Visibles||In this menu, we can select the needed layer in editing time.|
1. Click on icon “Read Net list”, a window will appear on the screen. Browse to saved Net list file, and open it. Footprints with local rats nets, will appear in PCB new window.
2. These may look clumsy and arranged randomly. Even recognizing components is also difficult. To spread this clumsy arrangement in a proper way, select “Mode footprint” in the top toolbar. Right click on the worksheet and under “Global spread and Place” option, select “Spread out all footprints”.
Fig. 2: Screenshot of Clumsy Footprints
Steps: select Mode footprint > Global spread and place (Right click options) > Spread out all footprints.
Fig. 3: Screenshot of Spread out Footprints on PCB Layout
3. After this step, we can see that all components are arranged one after another properly. Now we can select each component without confusion.
4. Before arranging components on the board, place the board edges (Board dimensions must be selected as per requirements). Board edges can be drawn using “place graphical line” option in the Right toolbar.
Note: Select Edges layer, when placing outlines.
5. Now select the components and place them on the board selectively.
Note: When placing components on the board, select the component and place them carefully and wisely. Place component beside to connect track easily. Try to place all components within the area of the board, if possible.
Note: Check the pads, when trying to place the components on both sides of the board.
Fig. 5: Screenshot of Pads on PCB Layout
6. We can check these components arrangement that’s how it may look in reality, using 3D view option.
Fig. 6: Image of 3D View of PCB
Fig. 7: Image of 3D View of PCB
7. Before connecting tracks, hide the local ratsnets. Select “Place track” and start the connections.
8. While placing track at the point, we can see the remaining connections available with that pad. So, we can easily connect tracks.
9. If connections are overlapping, place the via, and connect the track in the bottom layer. Using vias we can connect many tracks without overlapping.
10. When connecting tracks and placing vias, we have to take care of pads of all components. We cannot overlap the pads.
11. The arrangement of the components and tracks can be checked in the 3D view.
In video tutorial we see how to use vias and placing tracks. In this tutorial, I have explained only two layers of PCB. So, here we can see only through hole vias, not blind vias. In 3D view, I have shown how through holes are placed on the board.
Filed Under: Tutorials