By: Tai Nguyen, 10-22-2003
This tutorial will server as a basic guide to create your own PCB board using
Estimate time need to complete: 2 hours.
Step are as follow:
Before we begin, you should now know the size of your component include its
widtch, length, and height... PC TRACE prompt you with grids divided into 0.05
inche. Thus if your component is 0.1 inche wide, most component is at this size,
then it occupy 2 dots. This sound silly but it work for me when it comes to
create new definition files for components.
Next, you should have a clear view of where you want to place your parts. This is a time consumming process where you have to plan it such that no conection short out each other.
Setting the snap grid line: we can change the grid to snap onto different value by going the tab "setup" then chose "set up snap to" this enable you to set the automatic snap point to an value in unit inches. Unless you know what you are doing, I suggest leave the snap to 0.05 while drawing, else you will find yourself in deep trouble when you make a mistake. For example, after drawing a label, and the snap was at 0.01 when you make it. While working in snap of 0.05, it is very difficult to select this lable for editting; which you than need to change the snap point to 0.01 to fix it and the switch back to 0.05. Also, a board that different snap system will create problem when printing the circuit. I have a problem where I use snap of 0.01 and when the printing service compile the gerber files, thing wasn't in place that I wanted before. So to make is short, try to stick to .05
You should see a bar with icon at the top. These are all the basic of a program that you would already know. The one that need emphasize are label "C", "Si", "So". There three are very important while you are putting part or running connection. In general, there are 3 layers: the top layer which is the component layer denoted by "C", the second is the silk layer which contain the label of each component denoted by "Si". The last one is the Solder layer which is the bottom layer denoted by "So". When ever you choose to put a component onto the board, you should consider if this component should appear on the top and bottom layer. This goes for running wire also. The top are always in Blue and the bottom are in red color, and least, the silks are in green.
By carefull layout, you can have some wire running at the top level and together have wire running at the bottom level for the same board area. This technique will help save space and less confilct in wirring. to connect between the top and the bottom layer, you just simply add a drilled pad there and this is your tunnel the the other layer.
The other on the menu are the Arrow which let you on selecting mode. You can select, drag part arround and edit them by double click on some. The darck circle is the Pad, this is where you decide if you want to put a pad with hole that get drilled for putting a chip through, or use surface mounted part. This is up to you. After placing the pad, you can change it's size by either double click and change the size; or you can go to setup menu, choose "change pad to" and specify the size you want. Now, go back to the menu and choose the button on the right of "Tr",the one with the red arrow on it. After click this, every pad that you click will change its size, shape to the one you specify in the set up. This is helpfull when you need to change alot of pad's size at once.
It's should looks like this. You can see, the round with a hole in the middle, that hole will be drill to put the IC's pin in. You want to make this pad's size at least 0.1' larger than the size of the drill. Populard size for the pad is at 0.6 - 0.7
Now, look at the rectangle, you can customize the size of the length and width of your pad by fixing the x and y dimension. When you want to build your own definition files for surface mounted component. you can actually use these to make the layout.
Now, always keep in mind that the bottom layer will be reflected through the vertical axis to match the board when printed. For example when you are viewing the Solder side; this is how it's look like as you can see through the board from the top. When it is printed, it is mirror to match the top.
You can select which side of the board you want to view by going to setup and go to set up visible side. You will see that anything at the top will by in blue, anything at the bottom will be in red.
Now, open up PC TRACE, make sure the snap is set to 0.05. Go to set up menu and choose set path names. This is where the directory of your definitions files. Think of the defs files as the the header files in C or C++. It has the template of the component that are popular. This way you don't have to manually put in the pad everytime.
Now after put in the directory. Go to Data, enter component. You should see a list of some Defs files already in there. Let do one for example, choose "sip2v.def", hightlight it. Where it say designation, this is where you name your component. For example. sipv2 is a vertical 2 pin component such as resistor or capacitor. I will call it R1, of C2.
Ok, now press add new. You should see 2 pins appear on your board lay out. You can select and drag them accroding to your plan.
You might want to add a text label for each one by selecting the text insert icon "Tx". Click near the component you want to name, then you will be promt for the name. Enter it and click ok. You can change its orientation by choosing the rotation degree.
Here is an example.
Sometime, when you change something, it's seem like the board is messed up. Just go to view, and choose regen. This will refresh the board.
Now running traces. You should have done this ahead of time to save you the headed and time. When running trace becareful of wire crossing. Select Tr from menu, now which side (layer) do you want to run this trace? Chose the appropriate layer and start the trace. Below is an example of the trace, again, blue is top, red is bottom. You should always label the top and bottom by enter text on each layer. When the tecnichian put the board to the printing machine, they know which side to mirror.
Ok, I was able to over lap the red and blue on the right. The lable Top appear in blue which only appear at the top leve. When you do a set visible to only top, you will only see the blue part.
Here is aother example.
Note that you want to cut the corner at close to 45 degree angle. This reduce the heat generated when electrons hit the corner if make at 90 degree.
Now if you want to create your own definition files. Start the DEFGEN and you can build your own. You might want to open some existing Def and study it. Don't forget to save it as something else if you are just modifying it. If not it will be saved over and you will lose that Def files.
The Gerber file is the primary method used for producing printed circuit boards. Most manufacturers prefer this file when manufacturing boards. PC-Trace creates these files when the Export Gerber File choice is selected from the FILE menu. PC-Trace uses the base filename given by the user and a different extension for each layer. The extensions and their associated layers are listed below.
.gtl Board outline
.gcl Component layer image
.gcm Component layer solder mask
.gsl Solder layer image
.gsm Solder layer solder mask
.gsk Silkscreen layer image
.gdr Drill mask, excellon format drill coords. and tool for each appature
.gap Appature list for gerber files that were output
.gad List of tools and appature they were associated with