About circuit division in Protel

The positive layer is generally used to go pure lines, including outer and inner lines. The negative layer is mostly used as a stratum and power layer. Because the ground and power planes in a multilayer board typically use a whole piece of copper as the line (or as a partition of several larger blocks), if the picture is made with a MIDLAYER, ie, a positive slice, it must be used. The method of copper plating is implemented, which will make the entire design data volume very large, which is not conducive to the data exchange and will affect the design refresh rate. With a negative film, only a flower hole (THERMAL PAD) can be generated at the junction between the outer layer and the inner layer, which is very favorable for design and data transmission.

Adding and deleting inner layers

In one design, you sometimes encounter the situation of changing the board. For example, change the more complicated double-panel to four-layer board, or upgrade the four-layer board with higher signal requirement to six-layer board. In this case, you need to add an electrical layer. You can do the following:

DESIGN-LAYER STACK MANAGER, on the left there is a schematic diagram of the current layered structure. Click on the top layer you want to add a new layer to, such as TOP, then click ADD LAYER or ADD PLANE on the right to complete the addition of the new layer.

Note that if the new layer makes the PLANE layer, it is necessary to assign the new layer to the corresponding network (double-click on the layer name)! There can be only one network allocated here (generally a GND is assigned to the layer). If you want to add a new network to this layer (for example, as a power layer), you need to do the inner layer splitting in the following operations. Therefore, here you need to allocate a network with a large number of connections.

If you click ADD LAYER, a new MIDLAYER will be added. The application method is exactly the same as the outer circuit.

If you want to apply a hybrid electrical layer, that is, a large copper plane with both traces and power supplies, you must use ADD LAYER to generate positive slices (for the reasons below).

Internal electrical layer division

If you have more than one set of power supplies in your design, you can use internal splitting to distribute the power supply network in the power plane. The command to use here is:

PLACE-SPLIT PLANE, set the layer in the dialog box that appears, and specify the network to be allocated for this split at CONNECT TO NET, and then place the split area according to the method of laying copper. After the placement is completed, the holes with the corresponding network in this divided area will automatically generate the flower hole pads, ie, the electrical connection of the power layer is completed. This step can be repeated until all power supplies have been assigned. When there are many networks that need to be allocated in the internal electrical layer, it is too much trouble to do internal segmentation and it needs to be done using some skills.

Here also need to pay attention to a problem: PROTEL there are two large copper electrical connection (not including PLACE FILL), one is POLYGON PLANE, that is ordinary copper, this command can only be applied to the positive layer, including TOP /BOT/MIDLAYER, the other is SPLIT PLANE, that is, the internal electrical layer division, this command can only be applied to the negative layer INTERNAL PLANE. Care should be taken to distinguish between the use of these two commands.

Modify the split copper command: EDIT-MOVE-SPLIT PLANE VERTICES