The layer settings of protel99 are separated from the inner electrical layer

The electrical layers of protel99 are divided into two types, open a PCB design document press, shortcut key L, the layer settings window appears. A signal layer on the left is a positive layer, including top layer, bottom layer, and midlayer. The internal planes in the middle is a negative layer, that is, an internal layer. The two layers have completely different properties and usage methods.

The opening layer is generally used to take pure lines, including outer and inner lines. The negative layer is used for formation and power supply layer. The reason is that the formation and power supply layer of the multilayer generally use the whole piece of copper as the line (or as a few large segments ), if you use the midlayer, that is, the front layer, for painting, you must use the copper paving method. This will make the entire design data size very large, not conducive to data exchange and transmission, and will affect the design refresh speed. However, when using a negative slice, you only need to generate a thermal pad at the link between the outer layer and the inner layer, which is very beneficial for design and data transmission.

Inner Layer addition and Deletion

In a design, the Board layer may be changed sometimes. For example, you can change a complicated double panel to a four-layer board, or upgrade a four-layer board with higher signal requirements to a six-layer board. You need to add an electrical layer as follows:

Design-layer stack manager, with the current cascade structure on the left. Click the layer above which you want to add a new layer, such as top, and click Add layer or add plane on the right to add the new layer.

Note: If the new layer enables the plane (negative) layer, you must allocate the corresponding network to the new layer (double-click the layer name )! Only one network can be allocated here (generally one Gnd can be allocated to the formation). If you want to add a new network to this layer (such as the power supply layer, in the subsequent operations, we need to split the layers to achieve this. Therefore, we need to allocate a network with a large number of connections.

If you click Add layer, a new midlayer (main part) is added. The application method is the same as that of the outer line.

If you want to apply the hybrid electrical layer, that is, the method of having both the strip and the power of the copper surface, you must use the add layer to generate the opening layer (for the reason, see below ).

Division of the inner electrical layer

If there are more than one power supply group in the design, you can use the inner layer to allocate the power network in the power supply layer. The command used here is:

Place-split plane, set the layer in the displayed dialog box, specify the network to be allocated for this split at connect to net, and then place the split area according to the copper paving method. After placement is complete, holes with corresponding networks in this split area will automatically generate flower hole pad, which completes the electrical connection of the Power layer. You can repeat this step until all power supplies are allocated. When the inner electrical layer requires a large number of networks to be allocated, it is difficult to separate the inner layer. You need some skills to complete this process.

In this case, you also need to pay attention to one problem: Protel has two kinds of Large Copper electrical connection methods (excluding place fill), one is polygon plane, that is, normal copper-clad, this command can only be applied to the front-slice layer, including top/BOT/midlayer, and split plane, that is, the inner electrical layer. This command can only be applied to the negative layer, that is, internal plane. Note that the use range of these two commands should be distinguished.

Command for modifying split copper pad: Edit-Move-split plane vertices