PCB routing rules (same as for reference to others)

Source: Internet
Author: User

Wiring rules are set up the wiring of the various specifications (such as the use of the plane, the width of the lines, the spacing between the holes, the topology of the layout of some of the rules, can be exported through the Design-rules menu from other boards, and then import the board) This step does not have to be set every time, according to personal habits, set once.

Select Design-rules generally need to re-set the following points:

1, the Safe spacing (Routing label Clearance Constraint)

It specifies the distance that must be maintained between the cross-hole of the wire for different networks on the board. The general board can be set to 0.254mm, the more empty board can be set to 0.3mm, the more dense patch board can be set to 0.2-0.22mm, a few printing plate processing factory production capacity in 0.1-0.15mm, if you can obtain their consent you can set this value. 0.1mm below is absolutely forbidden.

2. Line level and direction (routing label Routing Layers)

Here you can set the track layer used and the main direction of the route for each layer. Please note that the single-panel SMD only with the top layer, the straight-type single panel only with the bottom, but the multilayer board of the power layer is not set here (can be in the Design-layer Stack Manager, point top or bottom, with Add Plane added, with the left mouse button double-click after setting, After the point in this layer is deleted with delete), the mechanical layer is not set here (you can select the desired mechanical layer in the design-mechanical layer and choose whether it is visible and whether it is displayed in single-layer display mode).

Mechanical Layer 1 is generally used for the border of the artboard;
Mechanical Layer 3 is generally used in the drawing board sub-bar and other mechanical structural parts;
Mechanical Layer 4 is generally used to draw rulers and notes, etc., specifically, you can use the PCB Wizard to export a PCAT structure of the board to see

3, through hole shape (routing label routing Via Style)

It specifies the manual and automatic routing of the automatic generation of vias, the inside and outside diameter, are divided into the minimum, maximum and preferred value, wherein the preferred value is the most important, the same.

4. Line width (width Constraint of routing label)

It specifies the width of the traces when manually and automatically routed. The entire board range of preferences generally take 0.2-0.6mm, add some network or network group (NET Class) line width settings, such as ground, + 5 volt power cable, AC power input line, power output line and power group, etc. Network group can be defined in advance in Design-netlist Manager, the ground is generally optional 1mm width, a variety of power lines are generally optional 0.5-1mm width, printing board and the relationship between the current and the line width of approximately 1 amps per millimeter allowed to pass the current, specific information can be see. When the line diameter preference is too large to make the SMD pad in the automatic wiring can not go through, it will be entered into the SMD pad automatically reduced to the minimum width and the width of the pad between the section of the line, wherein the board for the entire board of the line width constraints, it is the lowest priority, that is, the first time to meet the network and network

5. Setting of Copper connection shape (manufacturing label polygon Connect Style)

It is recommended to use relief Connect mode traverse width conductor width take 0.3-0.5mm 4 wire 45 or 90 degrees.

The rest of the items are generally available with its original default values, which can be set as needed, such as the topology of the cabling, the spacing of the power layer, and the network length that the connection shape matches.

Choose Tools-preferences, where the options bar interactive Routing to select push obstacle (when encountering different networks of the line to push other lines, Ignore obstacle for crossing, Avoid Obstacle to stop) mode and check automatically remove (automatically remove excess lines). The track and via of the Defaults bar can also be changed, generally do not need to move them.

Place the fill layer in the area where you do not wish to have a trace, such as the heat sink and the laying layer below the two-foot crystal oscillator, to put the tin in the top or bottom Solder corresponding place fill.

Cabling rules Setup is also one of the key to the printed circuit design and requires a wealth of practical experience.

Eight, automatic wiring and manual adjustment

1. Click the menu command Auto Route/setup to set the automatic routing function.

Select all except add testpoints, especially if the lock all Pre-route option is selected, Routing Grid is optional 1mil, and so on. Automatic wiring before the start Protel will give you a recommended value can not go to it or to its recommended value, the smaller the board is easier 100% cloth pass, but the wiring difficulty and the more time spent.

2, click the menu command Auto route/all start automatic routing

If not completely pacchiosi can be manually continue to complete or undo once (do not use the Undo all cabling function, it will remove all pre-wiring and free pads, vias) After adjusting the layout or wiring rules, and then re-cabling. After completion of the DRC, the wrong is corrected. Layout and wiring process, if found that the schematic error should be updated in time schematic diagram and network table, manually change the network table (same as the first step), and re-install the network table after the cloth.

3. Manual initial adjustment of wiring

Need to bold ground, power lines, power output lines, such as bold, a few of the wires around too much to re-cloth, eliminate some unnecessary vias, again with the VIEW3D function to see the actual effect. Manual adjustment in the optional tools-density Map to see the cabling density, red is the most dense, yellow followed by, green is more loose, after reading can press the end key on the keyboard to refresh the screen. The red section should generally adjust the alignment to a little more loosely until it turns yellow or green.

Nine, switch to the single-layer display mode (click the menu command tools/preferences, select the dialog box in the display bar of the individual layer mode)

The lines of each routing layer are neatly and beautifully drawn. Manual adjustment should often do the DRC, because sometimes some of the line will be disconnected and you may walk from the middle of it to several lines, the completion of each wiring layer can be printed separately, in order to facilitate the change of the reference, in the meantime, often with the 3D display and density map function to view.

Finally cancel the single-layer display mode, save the disk.

If the device needs to be re-labeled click on the menu command tools/re-annotate and select a good direction, press OK button.

Go back to the schematic and select Tools-back Annotate and choose the new one that's created. was file, press OK. Some of the labels in the schematic should be re-dragged to look good, all finished and after the DRC passed, drag and drop all the characters to the screen printing layer to the appropriate location.

Note that the character should not be placed below the component or over the hole pad. For oversized characters to shrink appropriately, the drilldrawing layer can be placed on demand with some coordinates (place-coordinate) and Dimensions ((place-dimension).

Finally, the printed board name, design version number, company name, the first processing date of the document, the name of the plate, the file processing number and other information (see the Fifth step diagram shown). And can be provided by third-party programs to add shape and Chinese notes such as BMP2PCB.EXE and Acer company ROTEL99 and PROTEL99SE Special PCB Kanji Input Package in the FONT.EXE and so on.

Xi. tear drops for all vias and pads

The added tear drops increase their fastness, but make the line on the board more unsightly. In order to press the keyboard s and a key (select All), and then select Tools-teardrops, select the first three of the General column, and choose Add and track mode, if you do not need to convert the final file to Protel DOS version of the file, you can also use other modes, and then press OK button. When finished, press the X and a key of the keyboard (all unchecked). For SMD and single panel must be added.

12. Place the copper covering area

The safety spacing in the design rules is temporarily changed to 0.5-1mm and the error mark is cleared, and the Place-polygon Plane is placed on the ground network in each wiring layer (as far as possible with octagonal, instead of wrapping the pad with an arc. Finally to turn into a DOS format file, be sure to choose to use octagonal). An example of a set of copper cladding at the top level:

After the setting is complete, then press OK Twist, draw the border that needs to cover the copper area, the last edge can not draw, right click right mouse button to start covering copper. It defaults to a straight line between your start and end points, and the grid Size is larger than the track Width when the circuit frequency is high, covering the gridlines.

Corresponding to the remaining several wiring layer of copper, to observe a large area of a layer of copper-covered areas, in the other layers have a copper-coated place a hole, double-click on any point in the copper-clad area and select a copper, direct click OK, then click Yes to update the copper. Several copper-clad layers are repeated several times until each copper clad layer is more than full. Change the safe spacing in the design rules back to the original value.

13. Finally, one more DRC.

Select one of the clearance Constraints max/min Width Constraints Short circuit Constraints and un-routed Nets Constraints These items, press the Run DRC button, there Wrong is correct. All right and save the disk.

14, for the Support Protel99se format (PCB4.0) processing manufacturers can view the document directory, the file is exported to a *. PCB file; For manufacturers that support PROTEL99 format (PCB3.0) processing, save the file as a PCB 3.0 binary file for the DRC. After passing do not save the exit. In the case of viewing the document directory, export the file as a *. PCB files. As a large part of the manufacturers can only do dos under the Protel autotrax Painting board, so the following steps are necessary to produce a DOS version of the PCB file:

1, all the mechanical layer content to the mechanical layer 1, in the case of viewing the document directory, the network table exported to *.net file, in the case of opening this PCB file view, the PCB exported to the Protel PCB 2.8 ASCII file format *. PCB files.

2. Open the PCB file with Protel for WINDOWS PCB 2.8, select Save As in the File menu, and choose AutoTRAX format to save the file as a DOS.

3. Open this file with Protel AutoTRAX under DOS. Individual strings may have to be dragged or resized again. All of the two-pin SMD elements on the lower part may produce a case of a pad x-y size swap, one to adjust them. The large four-column SMD IC will also be all pads X-y interchange, can only be automatically adjusted half, manually a change, please always save, this process is prone to human error. PROTEL DOS version does not have the undo function. If you have previously covered the copper and chose to wrap the pad with an arc, then all the network is now basically connected, manually a delete and modify these arcs is very tired, so the front recommended that you must use octagonal to wrap the pad. When these are complete, use the previously exported network table as the separation Setup in the DRC Route, the values should be smaller than the Windows version, and the error will be corrected until all the DRC has passed.

You can also directly generate Gerber and drill files to the manufacturers choose File-cam Manager next> button out six options, BOM for the list of components, the DRC for the design Rules Check report, Gerber for the light drawing file, NC drill for drilling files, Pick Place is the automatic pickup and drop file, and test Points reports to the testing point. Select Gerber and follow the prompts step-by-step. Some of the parameters related to the production process capacity need to be printed plate manufacturers to provide. Until the finish is pressed. In the generated Gerber Output 1, press the right mouse button, choose Insert NC Drill to join the drill file, and then press the right mouse button to select Generate CAM files to generate a real output file, the light drawing file can be exported with CAM350 open and check. Note that the power layer is negative output.

XV, send e-mail or copy disk to the processing factory, indicating the board material and thickness (to do the general board, thickness of 1.6mm, extra large plate available 2mm, RF Microstrip board and so on generally in the 0.8-1mm, and should give the board of the dielectric constant and other indicators), the number, processing needs special attention to the place. Call the manufacturer within two hours after email is sent to confirm receipt or not.

16. Produce the BOM file and edit it into a format consistent with the company's internal regulations.

17, the frame screw hole connector and other parts related to the chassis machining (that is, the other unrelated parts of the selected after the deletion), exported to the metric size of AutoCAD R14 dwg format files to the mechanical designers.

18, collate and print various documents. such as components list, device assembly diagram (and should be on the print scale), installation and wiring instructions, etc.

PCB routing rules (same as for reference to others)

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