Electronic Design - The setting of PCB working environment for PCB design

Introduction to PCB Design: Setting up the working environment of the PCB: Before we start to place the components on the board, we need to set up the working environment of the PCB, such as grid, layer and design rules. The PCB editing work environment allows PCB design to be expressed in 2D and 3D modes. Two-dimensional mode is a multi-layer, ideal environment for general PCB circuit design, such as placing components, circuits and connections. The three-dimensional mode is very useful for checking the surface and internal circuits of the user's design (the three-dimensional mode does not support all the functions in the two-dimensional mode). You can use: File>>Switch To 3D, or File>>Switch To 2D [shortcut keys are 2 (two-dimensional), 3 (three-dimensional)] to switch between two-dimensional and three-dimensional mode.

1. Grid

Before we start to place the components, we must make sure that the settings of our grid are correct. The grid composed of all aligned lines placed in the PCB working environment is called the snap grid. This grid needs to be set to match the circuit technology the user intends to use.

The circuit in the tutorial uses international standard components with the smallest pin pitch of 100mil. We will set the snap grid to the common factor of the minimum spacing, such as 50mil or 25mil, so that all the component pins can be placed on a grid point. In addition, the line width and safety spacing of our board are 12mil and 13mil respectively (the default value used by the PCB Board Wizard), and the minimum parallel line center distance is 25mil. Therefore, the most suitable snap grid setting is 25mil.

Getting started with PCB design: setting up the PCB working environment

To set up snap grid, complete the following steps:

Select Design>>Board Options[shortcut keys: D, O] to open the board Options dialog box.

Use the drop-down list or enter a number to set the value of Snap Grid and Component Grid to 25mil. Please note that this dialog box can also be used to define Electrical Grid. This grid acts when the user places electrical objects; it overrides the snap Snap gridGrid and snap electrical objects used in Component Gird. Click OK to close the dialog box.

Let's set up other Options that make it easier to place components.

Select Tools>>Preferences [shortcut keys: T, P] to open the preferences dialog box. Press the selection tree of PCB Editor-General in the dialog box (left panel) to display the page of PCB Editor-General. In the Edit Options section, make sure that the Snap to Center option is enabled. This ensures that when you "drag" a component and place it, the cursor is set as the reference point of the component.

Press PCB Editor-Display. In the DirectX Options section of the page, select the option Use DirectX if possible. As shown in Figure 6-16. This will allow us to take advantage of the latest 3D view modes. Press OK to close the Priority Preferences dialog box.

Note: Altium Designer's 3D view mode requires DirectX 9.0c and Shader Model 3 or higher to run, and a suitable graphics card. If the user cannot run DirectX, the user will be restricted from using the 3D view.

2. Define the view settings of the layer stack and other non-electrical layers

View Configurations includes many display options for the 2D and 3D environment of the PCB workspace and settings suitable for PCB and PCB library editing. When saving any PCB file, the last view settings used will also be saved. This allows it to be invoked by another instance of Altium Designer that uses its associated view settings. View Configurations can also be saved locally and used and used for any PCB file at any time. When the user opens any PCB file without related View Configurations, it will use the system default configuration.

Note: The View Configurations dialog box provides layer 2D color settings and other system-based color settings-these are system settings, they will be used in all PCB files, and are not part of View Configurations. The color profile of the two-dimensional working environment can also be created and saved, and can be used at any time to call up, as is the view configuration.

Introduction to PCB Design Setting up the PCB working environment Select Design>>Board Layers & Colors[shortcut key: L] to open the View Configurations dialog box from the main menu. This dialog box allows you to define, edit, load and save view settings. Its settings are used to control which layers are displayed, how to display common objects, such as copper, p, pads, lines, strings, etc., display network names and reference marks, transparent layer mode and single layer mode display, three-dimensional surface transparency And color and 3D PCB overall display.

Users can use the View Configurations dialog box to view or select them directly from the drop-down list in the PCB's standard toolbar. The view setting dialog box is shown in the figure below.

If the user looks at the bottom of the PCB workspace, the user will see a series of layer labels, most of the editing actions performed by the user are on a certain layer.

There are three layers in the PCB compiler:

Electrical layers-It includes 32 signal layers and 16 internal electrical layers. Electrical layers can be added or removed in the Layer Stack Manager dialog box, select Design>>Layer Stack Manager to display it.

Mechanical layers- It has 16 general purpose mechanical layers that determine the shape and size of the board, including the details of production or any other mechanical design details. These layers can be selectively included in printouts and Gerber's output. You can add, delete and name mechanical layers in the View Configurations dialog box.

Special layers- it includes the screen printing layer on the top and bottom, the mask layer of the solder resist layer and the paste layer, solder paste layer, drilling layer, Keep-Out layer (used to define electrical boundaries), multiple integrated layers (using For multilayer pads and vias), connection layer, DRC error layer, grid layer and via hole layer.

Let's create a simple two-dimensional view setup for this.

a. Select Design>>Board Layers & Colors[Shortcut Key: L] to open the View Configurations dialog box. Open the dialog box and select the action configuration under Select PCB View Configuration. If the user is in 3D mode, click on the 2D configuration.

b. In the Board Layers & Colors page, select Only show layers in layer stack and Only show enabled mechanical layers options. These settings show only the layers in the stack.

c. Click the Used Layers On button on the page. Make it only show the layers that are being used. That is, there are layers designed on top.

d. Click the color next to Top Layer to display the 2D System Colors dialog box and select #7 (yellow) from the Basic color list. Click OK to return to the View Configurations dialog box.

e. Click the color next to Bottom Layer to display the 2D System Colors dialog box and select #228 (bright green) from the Basic color list. Click OK to return to the View Configurations dialog box.

f. Click the color next to Top Overlay to display the 2D System Colors dialog box and select #233 (white) from the Basic color list. Click OK to return to the View Configurations dialog box.

g. Make sure that the four Mask layers and Drill Drawing layers will not be shielded by the Show option of each determined layer.

h. In the Actions selection, click Save As view configuration and save the file such as tutorial.config_2dsimple.

i. Click OK when the user returns to the View Configurations dialog to apply the changes and close the dialog.

Note: Remember that the 2D layer color setting is system-based and will be applied to all PCB files, not part of any view file. Users can create, edit and save 2D color setting files from the 2D System Color dialog box.

3.Layer Stack Manager (layer stack management)

The PCB of the example is a simple design and can be wired with a single-layer board or a double-layer board. If the design is more complex, users can add more layers through the Layer Stack Manager dialog box.

a. Select Design>>Layer Stack Manager [shortcut keys: D, K] to display the layer stack management dialog box, as shown in the figure below.

b. The new layer will be added below the currently selected layer. Layer electrical properties, such as copper thickness and dielectric properties, will be used for signal integrity analysis. Click OK to close the dialog box.