1. Software installation: This example installs version AD17.1.
2. The basic concepts that need to be mastered before drawing the PCB board:
2.1 A complete pcb file generally includes project files (.PrjPcb), pcb files (.PcbDoc), schematic files (.SchDoc), and pcb package library files (.PcbLib).
Briefly introduce the relationship between them: the project file is a general file, and other related files are included in it. Pcb file is most of the files we need to draw, and it is also a file for the processing pcb manufacturer. The schematic file needs us to make electrical connections to the various components of the pcb board. A library of the pad size of soldering components is needed (the pcb package library we need can also be exported according to the drawn pcb board).
2.2 Before drawing the circuit board, you should have a basic understanding of some basic concepts and operations of the pcb board. According to my initial learning experience, I listed a few concepts that I think need to be understood.
Layer concept: PCB boards have various layers. Below - its introduction:
2.2.1 Signal layer (signal layer)
The signal layer is mainly used to arrange the wires on the circuit board, and it is also the main operation layer for us to draw the pcb diagram, such as Top layer (top layer), Bottom layer (bottom layer), and 30 MidLayers (middle layer).
2.2.2 Internal plane layer (internal power supply/ground layer)
This type of layer is only used for multi-layer boards, mainly used to arrange power lines and ground lines. We call double-layer boards, four-layer boards, and six-layer boards, which generally refer to the number of signal layers and internal power/ground layers.
2.2.3 Mechanical layer
It is generally used to set the overall dimensions of the circuit board, data marks, alignment marks, assembly instructions and other mechanical information.
2.2.4 Solder mask layer (solder mask layer)
A layer of paint, such as solder resist paint, is applied to all parts other than the pads to prevent these parts from being sawed. Soldermask is used to match pads during the design process and is automatically generated.
2.2.5 Keep out layer (disable wiring layer)
Used to define areas on a circuit board where components and routing can be efficiently placed. Draw a closed area on this layer as the routing effective area, outside of this area cannot be automatically placed and routed.
2.2.6 Silkscreen layer (silk screen layer)
The silk screen layer is mainly used to place printed information, such as the outline and labeling of components, various comment characters, etc., just to facilitate the comments on the PCB board during assembly and maintenance, such as the serial number of the resistor. size.
2.2.7 Multi layer (multi-layer)
The pads and penetrating vias on the circuit board need to penetrate the entire circuit board to establish electrical connections with different conductive pattern layers. Therefore, the system specially sets up an abstract layer-multilayer. Generally, pads and vias are arranged on multiple layers. If this layer is turned off, the pads and vias cannot be displayed.
2.2.8 Drill layer
The drilling layer provides drilling information in the circuit board manufacturing process (such as pads, via holes need to be drilled). Protel99 SE provides two drilling layers, Drillgride (drilling instruction map) and Drill drawing (drilling map).
2.3 Some basic operation concepts of drawing pcb board.
2.3.1 Copper laying: If there are many grounds on the PCB, such as SGND, AGND, GND, etc., it is necessary to use the most important "ground" as a reference to independently obtain copper according to the position of the PCB board, that is, is to connect the ground together.
Benefits are:
1) Reduce the impedance of the ground wire and improve the anti-interference ability;
2) Reduce voltage drop and improve power efficiency;
3) Connecting to the ground wire can also reduce the loop area.
4) Also for the purpose of keeping the PCB from deforming as much as possible during soldering, most PCB manufacturers will also require the PCB designer to fill the open area of the PCB with copper or grid-shaped ground wires.
2.3.2 Pad: Used to realize the electrical connection between the component and the PCB board. The through holes of the pads are used to solder the pins of in-line components.
2.3.3 Vias: Used for layer switching during routing. in order to achieve the required electrical connectivity.
2.3.4 Flying lead: The line displayed by the electrical connection relationship between components when we are laying out, which is convenient for layout.
At this point, we almost start our real journey of drawing circuit boards.
2.3.5 Common shortcut keys:
Flying lead connection display N
Single layer display Shift +s
Press L while dragging the device to switch between the front and back of the device placement position
Place Via Shift + xtrl +F2
3. Drawing step beam:
3.1 Create a project. Create a new "PrjPCE" file.
3.2 Add the existing schematic diagram and package library to the project.
3.3 Determine the size of the pcb board (draw the size of the board in the kcep out layer, after the drawing is completed, select the wireframe, and in the design of the shape of the board, choose to define according to the selecte object and press the shortcut key DSD)
3.4 Schematic compilation inspection and troubleshooting
3.5 Matching import of packaging library and schematic diagram. until there are no errors
3.6 Then there is the specific layout and connection, just go through it from the beginning to the end in combination with the video.
3.7 Rules check: Before drawing the PCB board, it is necessary to check the rules to avoid mistakes. It is very important, and it is explained in the video. Prepare to follow up with the common rules.
