Home | Contact Us
  Learn More Try Now
        BoardMaker3
Features
Guide
        Product Costs
        Contact Us
        Downloads
        Services
Article Index
Schematic
Attributes
Footprints
PCB


PCB's

An introduction to BoardMaker3 PCB's

General Features

  • Fast Custom Graphics Engine
  • High Resolution Database
  • Large Working Area
  • Destination, net and route highlighting
  • Most operations available on single keystrokes
  • MDI interface, see both the PCB and schematic on the screen at the same time
  • Dynamic closest node ratsnest
  • Full plane DRC
  • Autopan
  • Net Names/Pin Numbers in pads

BoardMaker3 supports up to 32 copper layers. In addition to this, it supports layers for Paste Mask, Solder Resist and Glue Layers. The software currently makes use of only a small fraction of the number of layers available. Future releases of the software will make use of these layers for additional features.

The preferred net import method in BoardMaker3 is to use the integrated schematic capture tool with schematics linked to PCBs. In addition to this mode, BoardMaker3 is also able to read in netlists generated in either BoardCapture or Tango format.

BoardMaker3 contains powerful routing features, a brief description of some of these are described below.

Planes

The planes in BoardMaker3 are completely dynamic. This means that copper placed on the same layer as a copper plane will automatically plough its way through the plane leaving a user-definable clearance around the tracking. The plane display is maintained in realtime and the designer is able to see the exact plane as it will appear when the gerber output is generated.

This includes a clear display of the thermal break connections which join the vias or component pins to the plane. There is no lengthy copper pouring process and the refresh of the plane display is instantaneous. A transparent mode is also provided when the plane layer is not being used for routing.

Planes themselves are defined using polygons. Any number of planes can be placed on any of the copper layers and one net can be assigned to several planes over one or more layers. This flexibility allows a ground plane to be placed on multiple layers or alternatively an internal layer to used for different planes in different regions of the board. Complex planes can be built from several overlapping polygons.

As well as the basic plane objects, a number of other objects are provided to allow more control over the planes, these are:

Polycut

The polycut is useful for cutting away large irregular shapes in the plane, the polycut will only "eat" plane copper, so it's perfectly safe to run a polycut over tracks and pads. This tool together with the Linked Cut allows planes to be tidied up after placement. Areas of the plane can be trimmed away and additional clearances can be created as necessary.


Linked Cut

The linked cut also cuts away plane copper like the polycut above, but linked cuts are rounded. The Polycut can be used to remove large irregular areas quickly. The linked cut provides an alternative mechanism which can be used around mounting holes for example or along rows of pads.





Thermal Break

Because all regular copper objects (tracks, vias etc) plough through the plane, a special object is required to make a connection with a plane. In most PCB design tools, the thermal break is built into the pad. In BoardMaker3, the two objects are separate and the user is given complete control over the thermal breaks. Thermal breaks can be added manually or automatically. The automatic process will attempt to intelligently place the thermal breaks to complete the routing. The user can select several parameters to control the process including prong count, orientation, width etc. Once the automatic process has been run, the user can manipulate the thermal breaks as necessary. For example additional prongs can be added or removed or prongs can be reoriented. Additional thermal breaks can be added on other layers or at other net points to improve the continuity of the plane.

Design Rule Checking

A comprehensive rule-based design rule system is included with the software. The user can create any number of rules in the system, and control is provided to select the order of precedence of these rules. This allows special case rules to be applied ahead of general tracking rules. A separate plane design rule checker is integrated in the software. A brief description of rule configuration is as follows:

General Options

In the general options, you can name the rule according to its function, for example, one of the default rules in the system is named "Drills Too Close". You also set up the clearance and which layer(s) the rule applies to. One of the more powerful features of the rules is the ability to determine the nets to which the rule is applied. Three options are provided:

  • Same - The rule affects items on the same net. For example, you could create a rule which imposes a minimum separation between surface mount pads and vias on the same net.
  • Different - The rule affects items of differing nets, so for example VCC and AVCC have to be 6mm apart.
  • Either - The net is ignored. This could be used for example to check that components are not placed too close together.

Source and Target options


These options control what the rule applies to, you have the ability to say which objects the rule is valid for (tracks, vias, holes etc) and more specifically you can limit the rule to certain nets and/or components. As an example this would allow you to make the rule only apply to plated through hole pads on component U2 on nets VCC and GND. This can be useful for example to override a rule which needs to be broken in a particular location.

Net and Component Groups

Another powerful feature is the ability to set up groups or components or nets. For example, you might have two separate pairs of power rails on a PCB which required additional segregation from each other beyond that of the inter-rail separation.




Output Formats

BoardMaker3 provides a number of standard output formats for production.

Gerber RS274X

The gerber format used by BoardMaker3 is RS274X. This is the extended gerber format and includes a number of extra features which the software makes use of. Aperture tables are embedded in this format and ground planes images are combined within a single file. The extended format also supports polygons.

Each gerber layer is written to a separate file, and that file is named logically, such that the user has control over the "base" filename, but the software appends the layer name to the file, so a user named file "CPU Module" would output "CPU Module - Top Layer.gbx".

Options are provided to enable the contraction of paste mask apertures and the expansion of photo resist apertures. Other options control the format of the gerber generation.

NC Drill

NC Drill can be output in metric or imperial, some manufacturers differ in the way that they prefer to handle NC files, so the software gives the user the option of generating separate files for plated and non-plated holes or the option of a combined file (which contains comments that tell the manufacturer which drill codes correspond with plated and non-plated holes) .

Pick and Place

The supplied libraries for surface mount components include pick and place centroids. The software is able to make use of these in the PCB editor to generate a file which contains a list of these components together with their Designator, X,Y position and rotation. This file is used by the manufacturer to enable automatic placement. Separate files are produced for the top and bottom of a double-side mounted PCB.

DXF

The DXF output is useful for taking the PCB design over to a mechanical drawing system. If you have an enclosure which has to fit the PCB then it's easy to export the DXF from BoardMaker3 into your mechanical drawing package. You can also import a board outline defined in DXF format to be used in BoardMaker3.

BMP and Printing

The BMP and printing outputs are very closely related. The bitmap output allows the user to create images which could be embedded into documents, the user has control over which part of the image is output and the resolution of the output image.

The printing output has a number of controls which allow the user to control the formatting of the printout.

  • Control of the size of print, the user may fit the printout to the size of the page, they can scale the printout to a given percentage and there is also an option to posterise a printout if the destination size is smaller than the page size.
  • With layer control, the user has the ability to select which layers are to be printed, and whether layers should be merged or printed as separate pages
  • Miscellaneous controls including reversing the printout, colour control printing only a required section etc.
  • With a suitable printer driver, the software can produce PDF files.


Grids and Datums

Datums are objects which can be placed to denote places of interest, for example you could place a datum at the edge of the board to denote the board edge and place another datum inside where a keypad is to be placed.

The grids in BoardMaker3 are relative to the current origin, functions are provided which allow you to quickly move the origin to the position of a datum, this can prove to be useful when placing objects at specific locations on a special grid, a notable example of this may be a keypad matrix.

Furthermore, the grid system in BoardMaker3 is designed to allow the user to define any number of grids, and these can be switched at the press of a button. The configuration options for a grid allow the user to define a grid with differing pitches for X and Y, this is particularly useful when designing footprints.

Special Features

Star Earth

The star earth track is a powerful feature for designers with multiple ground nets which need to be shorted at a single point. Generally designers solve this problem in CAD software by routing their design with all the grounds separately, they confirm that the design is complete by using the DRC. Once they are satisfied with the results they then short all the grounds together using a track. This presents a number of problems, firstly once this track is added the design rules are violated, and secondly to continue working on the design they need to remove this track to stop the DRC violations, they then have to remember to place the track back once their modifications have been done.

In BoardMaker3 we introduced the Star Earth track (distinguished by it's stripy appearance), the track is ignored by the connection and clearance DRC's, instead a special DRC is run which checks the nets that are connected by the star earth track, the user is then told which nets are physically shorted together.

Using this feature the designer does not have to keep adding and removing tracks, the DRC continues to function as normal with information being displayed for the nets that are connected with the star earthed track.

Pre-Routes

Although Pre-Routes are defined in the schematic editor, they become useful in the PCB editor. Pre-routes are identifiable by a thin stripy line between 2 or more pins, the purpose of this line is to show the designer that those pins are internally connected in the device, this may be useful on a particularly dense section of board where it may be convenient to route through the component, the DRC in BoardMaker3 is fully aware and capable of handling these components.

Pin Swapping

Although the schematic capture tool has pin swapping, it's more likely that the designer would want to do this from the PCB. If a pin is swappable you can simply point at it and select the pin swap option, this will automatically swap the pins and update the netlist, it also sends this information back to the schematic so that the pins also swap on the schematic.



Home | Contact Us
@Copyright 2014 by Tsien (UK) Ltd. All rights reserved.