Search Security. Biometrics is the measurement and statistical analysis of people's unique physical and behavioral characteristics. Zero-day (computer). Download NetlistViewer for free. SPICE netlist visualizer. NetlistViewer is a tool capable of loading netlists in text format (currently only SPICE netlists) and convert them in a schematic (i.e graphical) form.
The PCB Import Wizard allows you to import 3Di, ODB++, IPC-2581, and Gerber (X1 and X2) standard files into the AWR Design Environment software.
In addition to importing 3DI files, the PCB Import Wizard can also import IPC-2581, ODB++ (archived file or unarchived directory) and Gerber (archived file or unarchived directory) standard files. To use the PCB Import Wizard to import an ODB++, IPC-2581, or Gerber file, open the wizard and set the Import Format to the desured standard, then browse to the file using Filename. For more information about this dialog box, see “PCB Import Wizard Dialog Box: Options Tab”.
- IPC-2581 - supports files conforming to the IPC-2581 (A and B) standard. Common enterprise tools that support this format are Cadence Allegro and Zuken CR-8000.
- ODB++ (file) - supports files conforming to the ODB++ (V7 and V8) standard. These files are typically produced from Mentor Graphics tools.
- ODB++ (dir) - same format as ODB++ (file) except it operates on already uncompressed archives.
- Gerber (file) - operates on a compressed directory of Gerber files conforming to the X1 or X2 standard. A Gerber Job file is recommended to be part of the directory.
- Gerber (dir) - same format as Gerber (file) except it operates on an uncompressed directory of Gerber files. A Gerber Job file is recommended to be part of the directory.
When you export from Allegro by choosing File > Export > IPC2581 the Functional Mode must be set to USERDEF for import into the AWR Design Environment software.
After the correct format and file are selected on the Options tab, the import creates a new
.lpf
file containing the layer definitions that are specific to the imported PCB. If there is more than one STEP in the associated file, a unique .lpf
is generated for each. You can view the layers on the PCB Import dialog box Layers tab. By default, only layers that contribute to the electrical portion of the design are imported. This selection is based on the Type of the layer. For IPC-2581, layers of type 'CONDUCTOR', 'PLANE', 'SIGNAL', 'MIXED', and 'DRILL' are imported. For ODB++, layers of type 'SIGNAL', 'POWER_GROUND', 'MIXED', 'DIELECTRIC', and 'DRILL' are imported. For Gerber 'CONDUCTOR' and 'DIELECTRIC' are imported. Selecting or clearing the Import check box next to the layer name determines whether or not it is imported. Type is for informational purposes, and Negative shows you which layers are negative layers. If you clear the check box, the layer is imported as positive.
All columns can be sorted by clicking the column title to toggle between no sorting, ascending, or descending. You can filter rows in the grid by typing a search string into the cell below the column title. The grid supports multi-selection using Shift + Click for range selection, Ctrl + Click for discontinuous selection, and Ctrl + A to select all cells in a column. See “Using Property Grids” for details on sorting, filtering, and selection within AWR Design Environment property grids.
The Nets tab shows all of the electrical nets specific to the PCB design.
Individual electrical nets are included or excluded from import by selecting or clearing the associated Import column check box. Once selected, pressing the Space bar toggles the state. The grid supports multi-selection using Shift + Click for range selection, Ctrl + Click for discontinuous selection, and Ctrl + A to select all cells in a column. See “Using Property Grids” for details on sorting, filtering, and the selection within AWR Design Environment property grids.
The Stackup tab displays stackup information found in the design file or synthesized from the file.
Not all files contain accurate stackup layer information like thickness, dielectric constant, or conductivity. If data is not found, N-1 dielectric layers, where N is the number of conductive layers imported, are added between the conductors and default values are used for missing data. Teeworlds hack aimbot. All data can be edited, including multi-select editing support. This information is used to create a STACKUP element in the schematic. The STACKUP will have AIR dielectric layers added above and below the core. The thickness of these layers of AIR is equal to 1/4 of the total dielectric thickness of the core. Finally, the top and bottom boundaries are set to approximate opens.
The following sections describe the manual steps you can follow using the PCB EM Setup tool to import a PCB, select a region of the PCB, and copy that region to an EM structure. See PCB EM Setup help page for download and use instructions.
After the PCB design is imported, you can select net names individually or as a group. All shapes with the same net name are considered to be part of the same electrical net, and the AWR Design Environment software can preserve these net names. Currently, net names do not drive connectivity but rather are present to aid selection by name. In a Layout View, choose Edit > Select By Name to display the following dialog box.
Choose one or more nets to select and click OK. Click Preview to zoom/pan to the selected net(s).
Alternatively, you can right-click a shape with a net name and choose Select By Name to select all other shapes with the same net name. This mode also supports multiple selected objects.
After you select the net(s) of interest, you can create an EM Clip Region and copy it to an EM structure.
- Select the shapes or clip regions, and choose Layout > Copy to EM Structure.The New EM Structure dialog box displays.
- Select a simulator and desired Initialization Options, then click Create.
- In the Simplification Properties dialog box, select the Decimation Options to apply, and click OK. See “Simplification Properties Dialog Box ” for more information.
EM Clip region allows you to trim a layout to manage its size and complexity for EM simulation. You can apply EM Clip region to only paths and polygon shapes in a schematic or EM layout.
To draw an EM Clip region in a schematic or EM document:
- Select one or more shapes and choose Draw > Create EM Clip Region.The Create EM Clip Region dialog box displays.
- Select Convert Selected to convert a polygon shape to an arbitrary clip region, as shown in the following figures.
- Select Bounding Box to draw a rectangular bounding box around the selected shapes. In Offset from Selected, specify the distance of the clip wall from the edge of the selected polygon(s), as shown in the following figures.
- Select Bounding Polygon to create a clip region by following the outermost vertices of the polygon with a defined offset.
- Select Outlines to joins the individual clip regions around the selected shapes if possible.
13.10.1.9. Clipping Shapes in Schematic Layout and Creating an EM Structure
To create an EM structure from a schematic layout, choose one of the following ways to send the shapes to the EM Structure:
Select shapes only: Select only the shapes and copy them to the EM structure.
Select clip regions only: Select the clip regions only and the resulting shapes are copied to EM structure. You can select more than one clip region.
Select both clip regions and shapes: Select both the clip regions and shapes inside to copy the resulting shapes to the EM structure. Only the selected shapes inside the clip region are clipped.
You can trim EM structures by adding clip regions and then performing a simulation of the desired shapes only.
- Clip regions in EM structure are drawn as described in “Trimming with EM Clip Region”. Clip regions in EM structures operate in both X-Y and Z planes.
- To clip the shape, choose Draw > Modify Shapes > Clip Shapes. You do not need to select a shape or clip area while performing this operation because it accounts for all the clip regions in the EM structure.
- If necessary, set the Z dimension of the clip region by selecting the clip region, right-clicking and choosing Shape Properties to display the Properties dialog box. On the Extrusion tab, set the top and bottom Z position as desired. This is helpful when there is a multilayer EM structure but you only want to simulate a few layers.
- Preview the EM structure to ensure the desired clipping is performed along with the geometry simplification rules. Preview geometry can be performed without the Clip Shapes operation.
- Perform an EM simulation if everything looks as desired.
13.10.1.11. Selecting PCB Pin Ports in an EM Structure
After the EM structure is created, if the copied geometry contained any pads identified as PCB pins, you can change them to EM ports by choosing Draw > Create Ports from PCB Pins. The Select EM Ports dialog box displays to allow you to add EM ports to existing PCB pins.
Imported 3Di files have a number of benefits:
- A schematic is created with placeholders for components.
- A layout is created using iNets to connect component footprints.
- Drawing layers and colors match the original database.
- A STACKUP element is created with all available dielectric information from the original database.
- The output document is ready to use the AWR extraction flow (see “EM: Automated Circuit Extraction (ACE)”).
The following figures show examples of an imported schematic, layout, drawing layers, and EM STACKUP.
With the proper software license, you can run the PCB Import Wizard after downloading it from the AWR website 'Download Site' Products tab (www.awrcorp.com/download/login). After installation, to access the wizard, open the Wizards node in the Project Browser and double-click PCB Import. The PCB Import - Options dialog box displays.
To import a
.3Di
file, set the Import Format to 3DI and browse to the file using Filename. For more information about this dialog box, see “PCB Import Wizard Dialog Box: Options Tab”. The following figures show commonly selected options.
Example circuit and layout with Highlight selected nets selected:
Example of whole component outlines, with Package Outlines selected:
The imported STACKUP has the dielectric and conductor information from the original database. You should verify these numbers for accuracy. The following figure shows the STACKUP material definitions.
The following figure shows the STACKUP materials.
The imported STACKUP always has Approx Open set for both the top and bottom boundaries. You should verify this setting. The following figure shows the STACKUP boundaries.
If you are using Automated Circuit Extraction (ACE), you should define the location of ground planes for conductor layers on the Element Options: STACKUP dialog box Line Type tab.
The schematic created in the AWR Design Environment software has the correct connectivity, but the actual components are unknown. To properly simulate the design you must add the component models to the subcircuits that are created. As a place holder, the model subcircuits simply contain PORT and LOAD elements. The following figure shows a schematic instance.
The following figure shows a default schematic instance model.
Commonly, you must add another node to the schematic subcircuit that represents the circuit stimulus (this is not necessary if the stimulus is a fully contained SPICE netlist file). The following figure shows a simple example circuit.
You can achieve this setup by modifying the top level subcircuits as shown in the following figures. Note that the third port added to the stimulus circuit appears as an additional pin on the top level schematic, which allows any desired voltage or current sources to be applied. The following figures show the stimulus circuit, receiver circuit, and the new top level schematic.
The following sections include information about layout shapes and extraction ports.
You can use any available EM simulator to simulate the
.3Di
layout shapes imported by the PCB Import Wizard. By default, layout shapes associated with nets on the schematic (iNets) are sent to the EM document. To add other shapes to the EM simulation (such as ground planes) simply select the shapes in the layout, right-click and choose Shape Properties, select the Enable check box under Em Extraction Options, and ensure that the Group name matches the Name parameter on the EXTRACT block on the schematic (the default value after import is 'EM_Extract'). AWR Design Environment EM engines support a variety of port types. See “Extraction Ports” for information on setting up and selecting the appropriate extraction ports.
During extraction, ports are placed on the primary face of area pins. Because pins in PCB tools are points (usually in the center of the footprint geometry) the PCB Import Wizard does not have sufficient information to put the primary face anywhere but the first footprint geometry edge that is drawn. This can result in EM pins placed in less than ideal locations during extraction. The following figure shows the default EM pin placement.
You can correct this by editing the appropriate component footprint and moving the primary face from the default location to the desired location. In the previous example, the primary face needs to be relocated from the 'top' of the footprint geometry to the 'bottom' of the footprint geometry. The following figure shows the original primary face location.
The following figure shows the modified primary face location.
As shown in the following figure, the extraction pins are now in the correct location.
Errors and warnings from the PCB Import Wizard display in the Status Window. If the Status Window is not open, you should open it after importing to check the contents.
Contact AWR Technical Support for more information about importing and simulating solder balls and bumps using the PCB Import Wizard.
In electronic design, a netlist is a description of the connectivity of an electronic circuit.[1][2] In its simplest form, a netlist consists of a list of the electronic components in a circuit and a list of the nodes they are connected to.[1][3] A network (net) is a collection of two or more interconnected components.
The structure, complexity and representation of netlists can vary considerably, but the fundamental purpose of every netlist is to convey connectivity information. Netlists usually provide nothing more than instances, nodes, and perhaps some attributes of the components involved.[4] If they express much more than this, they are usually considered to be a hardware description language such as Verilog or VHDL, or one of several languages specifically designed for input to simulators.
Netlists can be physical or logical, instance-based or net-based, and flat or hierarchical. The latter can be either folded or unfolded.
Contents and structure of a netlist[edit]
Most netlists either contain or refer to descriptions of the parts or devices used. Each time a part is used in a netlist, this is called an 'instance'.
These descriptions will usually list the connections that are made to that kind of device, and some basic properties of that device. These connection points are called 'terminals' or 'pins', among several other names.
An 'instance' could be anything from a MOSFET transistor or a bipolar junction transistor, to a resistor, a capacitor, or an integrated circuit chip.
Instances have 'terminals'. In the case of a vacuum cleaner, these terminals would be the three metal prongs in the plug. Each terminal has a name, and in continuing the vacuum cleaner example, they might be 'Neutral', 'Live' and 'Ground'. Usually, each instance will have a unique name, so that if you have two instances of vacuum cleaners, one might be 'vac1' and the other 'vac2'. Besides their names, they might otherwise be identical.
Networks (nets) are the 'wires' that connect things together in the circuit. There may or may not be any special attributes associated with the nets in a design, depending on the particular language the netlist is written in, and that language's features.
Instance based netlists usually provide a list of the instances used in a design.Along with each instance, either an ordered list of net names is provided, or a list of pairs provided, of an instance port name, along with the net name to which that port is connected. In this kind of description, the list of nets can be gathered from the connection lists, and there is no place to associate particular attributes with the nets themselves. SPICE is an example of instance-based netlists.
Net-based netlists usually describe all the instances and their attributes, then describe each net, and say which port they are connected on each instance. This allows for attributes to be associated with nets.EDIF is probably the most famous of the net-based netlists.
Hierarchy[edit]
In large designs, it is a common practice to split the design into pieces, each piece becoming a 'definition' which can be used as instances in the design. In the vacuum cleaner analogy, one might have a vacuum cleaner definition with its ports, but now this definition would also include a full description of the machine's internal components and how they connect (motors, switches, etc.), like a wiring diagram does.
A definition which includes no instances is called a 'primitive' (or a 'leaf', or other names); whereas a definition which includes instances is 'hierarchical'.
A 'folded' hierarchy allows a single definition to be represented several times by instances. An 'unfolded' hierarchy does not allow a definition to be used more than once in the hierarchy.
Folded hierarchies can be extremely compact. A small netlist of just a few instances can describe designs with a very large number of instances. For example, suppose definition A is a simple primitive, like a memory cell. Then suppose definition B contains 32 instances of A; C contains 32 instances of B; D contains 32 instances of C; and E contains 32 instances of D. The design now contains 5 definitions (A through E) and 128 instances. Yet, E describes a circuit that contains over a million memory cells.
Unfolding[edit]
In a 'flat' design, only primitives are instanced. Hierarchical designs can be recursively 'exploded' ('flattened') by creating a new copy (with a new name) of each definition each time it is used. If the design is highly folded, expanding it like this will result in a much larger netlist database, but preserves the hierarchy dependencies. Given a hierarchical netlist, the list of instance names in a path from the root definition to a primitive instance specifies the single unique path to that primitive. The paths to every primitive, taken together, comprise a large but flat netlist that is exactly equivalent to the compact hierarchical version.
Backannotation[edit]
Backannotation is data that could be added to a hierarchical netlist. Usually they are kept separate from the netlist, because several such alternate sets of data could be applied to a single netlist. These data may have been extracted from a physical design, and might provide extra information for more accurate simulations. Usually the data are composed of a hierarchical path and a piece of data for that primitive or finding the values of RC delay due to interconnection.
Format Factory
Inheritance[edit]
Another concept often used in netlists is that of inheritance. Suppose a definition of a capacitor has an associated attribute called 'Capacitance', corresponding to the physical property of the same name, with a default value of '100 pF' (100 picofarads). Each instance of this capacitor might also have such an attribute, only with a different value of capacitance. And other instances might not associate any capacitance at all. In the case where no capacitance is specified for an instance, the instance will 'inherit' the 100 pF value from its definition. A value specified will 'override' the value on the definition. If a great number of attributes end up being the same as on the definition, a great amount of information can be 'inherited', and not have to be redundantly specified in the netlist, saving space, and making the design easier to read by both machines and people.
References[edit]
File Format Converter
- ^ abHolt, Randy. 'Schematic vs. Netlist: A Guide to PCB Design Integration'. blog.optimumdesign.com. Retrieved 2019-04-03.
- ^'netlist.html'. www.vlsiip.com. Retrieved 2019-04-03.
- ^'Netlist File Format'(PDF). www.expresspcb.com. Retrieved April 2, 2019.
The netlist is written in a single file, but includes four sections: 1) A file header, 2) A table listing each of the components, 3) A table listing each of the net names, 4) A table listing each of the net connections. Every table entry is written using a single line of text that ends with a CRLF. The fields of the table are separated with Space characters (0x20). String fields begin and end with double quotes. Each of the three tables are terminated by a blank line (CRLF).
- ^'Example Circuits and Netlists | Using The spice Circuit Simulation Program | Electronics Textbook'. www.allaboutcircuits.com. Retrieved 2019-04-03.
Examples Of File Format
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Netlist&oldid=938837571'