Introduction to split Protel four-layer and inner electrical layer

I. Preparations
Create a DDB file, create the relevant schematic file, and prepare the PCB for the design. I believe all the friends who want to draw four layers will. I don't need to talk about it any more.

Ii. Create a file
Create a new PCB File and draw the outer frame of the pcb on the keepoutlayer. For example, if you have used Protel, you should.

3. Set the Board Layer
On the PCB page, click design on the main menu and click layer stack manager.

Click it to bring up the following layer Manager dialog box, because in Protel, the default is a dual panel, so we can see that there are only two layers of the wiring layer.

Now let's add a layer. First click toplayer on the left, and then click Add plane in the upper-right corner of the layer manager to add an inner electric layer, because we are talking about a four-layer board using a negative film method, we need to add an inner electrical layer instead of an add layer.
After clicking, a layer is automatically added under toplayer. Double-click the layer to edit the attributes of this layer, for example:

Enter VCC in the item corresponding to name, and click OK to close the dialog box, that is, change the layer to VCC as the power layer during design.
Add a Gnd layer in the same way. After completion

4. Import Networks
Go back to the schematic interface and click design ==> update PCB on the main menu:
=>
Select the PCB file to be updated and click Apply,

Click on the left to check whether the design in the schematic diagram is correct.

Here, we check the items and only view the wrong network.

You can click to import the network to the PCB file if no network error is found.
This network import method is a convenient way to import the schematic diagram of PROTEL into the network to the PCB. You do not need to generate a network table any more. At the same time, you can use this method to quickly update the PCB file after modifying the schematic file.

5. Layout
Because this is basically done by everyone, it is omitted. After completion:

6. Set the inner electrical layer
We will execute the layer stack manager under the main menu design to bring up the layer manager,

Double-click the VCC layer. In the pop-up dialog box, select VCC in the Net Name drop-down box, and define this layer as a VCC network. The previous step was just to get a VCC name, the same element pins and passing holes as the VCC network are automatically connected to the layer, so that no wiring is required.
Define the network for the Gnd layer in the same way and define it as a Gnd network. Click OK to close the dialog box. At this time, we found that in the PCB, the center of some Pad components has a cross, because the pad network is VCC or Gnd, indicating that it has been connected to the corresponding network.

In the figure, the color of the cross on the pad represents the color of the corresponding inner electrical layer. For example, if the inner electrical layer Gnd is brown, the cross of the pad is also brown.

VII. Wiring
[800 words ............ Omitted]

8. Division of the inner electrical layer
When the top layer and bottomlayer do not have enough space to deploy signal lines, but do not want to add more signal layers, we need to take these signal lines to the inner layer. The method is as follows:
First, confirm the network to go to the inner electrical layer, click the main menu place, and select an item.

The split inner layer dialog box is displayed,

In connect to net, select a network to deploy the inner electrical layer. Here, If we select aa1 network, in, we set it to 0.5mm, this is the distance between the Intranet and other networks. This should be set as large as possible, at least 3mm or above, generally 0.5mm, because, in the internal layer, the spacing is too small, resulting in high non-renewal during production. In layer, we select VCC (we do not recommend that you do not split the layer Layer, because the integrity should be maintained during design to improve the anti-interference capability .)
After setting, click OK and draw a line at the pad of the aa1 network in the PCB to enclose the pad or via on the layer to form a closed polygon. (Note that there is no copper area in the inner layer of this line, that is, the gap between the line on the top layer and the line. Therefore, it cannot be painted to overlap with the pad)

At this time, the pad center with the network of aa1 also has a cross, indicating that the aa1 network has connected the pad from the VCC layer. Note: Pay attention, do not wire these pad in the inner electrical layer.

9. Check the inner electrical layer
After the PCB inner layer is set, we need to check whether the inner layer is correct. Of course, we should first use the eyes to check the entire board. Next, let's take a look at the figure below:

As mentioned above, the cross pad has been connected to the corresponding network of the inner electrical layer. How can we check whether the pad is connected with copper and platinum? In fact, as long as the imagination is more abundant, people will know that the negative film in the PCB is: the place where there is a draw line is the area where there is no copper or platinum, so after the PCB is made in the middle and black areas, it is the area with copper and platinum. Now, we can use a simple method to view it.
First, on the PCB interface, click the main menu tool (or press the T or P shortcut keys under T) to open the Parameter Setting Dialog Box:

Then, click the color tab to open the color Settings dialog box,

For example, we want to view the VCC inner electric layer. Here, we set the color to a darker color, such as brown black. Then, set the background color to the normal red color, and click OK to close the dialog box.
Again, we turn off some other unnecessary layers, such as the Silk Screen Layer, so that we can view the PCB. Next let's take a look at the PCB File,

In the figure, the red area refers to the area with copper and platinum (that is, the area with no wire drawn in the inner electric layer). In the black area, there is no copper and platinum area (that is, the area with wire drawn in the inner electric Layer ), in this way, the board is like a PCB File with copper.
Last PCB file,

Haha, a four-layer board is complete !!!