Starting Mentor Graphics’ DxDesigner for the First Time Engineering Starting DxDesigner. Fall 7. As the instructions in the lab manual to use it . Starting Mentor Graphics’ DxDesigner Tool Suite for the First Time Engineering Starting DxDesigner. Fall See the ENGN manual for more. This tool can be used to simulate circuits using the DxDesigner schematic editor and the . do not need to manually save your design. B) Make.
If the board trace is designed poorly or the route is too heavily loaded, noise in the signal can cause data corruption, while overshoot and undershoot can potentially damage input buffers over time. As FPGA devices are used in high-speed applications, signal integrity and timing margin between the FPGA and other devices on the printed circuit board PCB are important aspects to consider to ensure proper system operation.
To avoid time-consuming redesigns and expensive board respins, the topology and routing of critical signals must be simulated. The high-speed interfaces available on current FPGA devices must be modeled accurately and integrated into timing models and board-level signal integrity simulations.
Timing is measured to the FPGA pin with no signal integrity analysis details. A complete point-to-point board trace model is defined and accounted for in the timing analysis. This can cause temporary glitches in the specified level of ground or V CC for the device. This chapter dxdesignsr intended for FPGA and board designers and includes details about the concepts and steps involved in getting designs simulated and how to adjust designs to improve board-level timing and signal integrity.
Finally, you should know how to set up simulations and use your selected third-party simulation tool. With the ability to create industry-standard model definition files quickly, you can build accurate simulations that can provide data to help improve board-level signal integrity.
In general, creating and running accurate simulations is difficult and time consuming. With these tools, you can set up and run accurate simulations quickly and acquire data that helps guide your FPGA and board design. IBIS models define the behavior of input or output dxdesgner through voltage-current V-I and voltage-time V-t data tables. These models can be changed as much as required to see how adjustments improve timing or signal integrity and help with the design and routing of the PCB.
Typically, if board signal integrity analysis is performed late in the design, it is used maunal a post-layout verification. The inputs and outputs of the FPGA are defined, and required board routing topologies and constraints are known.
Simulations can help you find problems that might still exist in the FPGA or board dxdeesigner before fabrication and assembly. When you understand the steps in the analysis flow, refer to dxdedigner section of this chapter that corresponds to the model type you are using. You can add series or parallel termination, specify the transmission line length, and set the value of the far-end capacitive load.
In fact, IBIS models ignore any board trace model settings other than the far-end capacitive load. If any load value is set other than the default, the delay given by IBIS models generated by the IBIS Writer cannot be used to account correctly for the double counting problem. For IBIS, a single file is generated containing information about all assigned pins. IBIS files downloaded from the Altera website must be customized with the correct RLC values for the specific device package you have selected for your design.
However, Intel recommends that you replace that model with a more detailed model that describes your board design more accurately.
Problem with DxPDF in DxDesigner
You can make additions or adjustments to the default simulation in the generated files to change the parameters of the default simulation or to perform additional measurements.
With IBIS models, you can apply them to input, output, or bidirectional buffer entities and quickly set up mankal run simulations. Warning messages during compilation alert you to this change. Most component manufacturers, including Intelprovide IBIS models for free download and use in signal integrity analysis simulation tools.
Dynamic OCT is used where a signal uses a series on-chip termination during output operation and a parallel on-chip termination during input operation. IBIS models downloaded and used for simulations in this manner are generic. To simulate your design with the model accurately, you must adjust the RLC values in the IBIS model file to match the values for your particular device package by performing the following steps:.
Examples of custom assignments include drive dxdesiner settings or the enabling of clamping diodes for ESD protection. The effective capacitive load is based on the sum of the Near capacitanceTransmission line distributed capacitanceand the Far capacitance settings in the board trace model.
Resistance values and transmission line inductance values are ignored. LineSim is an early simulation tool. BoardSim is a post-layout tool that you use to analyze existing board routing.
You select one or more maual from a board layout file and BoardSim simulates those nets in a manner similar to LineSim. With board and routing parameters, and surrounding signal routing known, highly accurate simulations of the final fabricated PCB are possible.
This section focuses on LineSim. LineSim provides two methods for creating routing schematics: Cell-based schematics are based on fixed dxdesigned consisting of typical placements of buffers, trace impedances, and components.
Parts of the grid-based cells are filled with the desired objects to create the topology.
A topology in a cell-based schematic is limited by the available connections within and between the cells. A more robust and expandable way to create a circuit schematic for simulation is to use the free-form schematic format in LineSim. The free-form schematic format makes it easy to place parts into any configuration and edit them as required. This section describes the use of IBIS models with free-form schematics, but the process is nearly identical for cell-based schematics.
If you see a discontinuity or other anomalies at the destination, such as slow rise and fall times, adjust the termination scheme or termination component values. After making these changes, rerun the simulation to check whether dxdesignner adjustments solved the problem. In this case, it is not necessary to regenerate the.
By their nature, HSPICE decks are highly customizable dxdesignfr require a detailed description of the circuit under simulation. You can simulate with the default simulation parameters built in to the generated HSPICE decks or make adjustments to customize your simulation.
However, the usefulness of such simulations is directly related to the accuracy of the models used and whether the simulations are set up and performed correctly. If this hand-off is not handled correctly, the calculated manyal could either count some of the delay twice or even miss counting some of the delay entirely.
HSPICE models for board simulation measure t PD propagation delay from an arbitrary reference point in the output exdesigner, through the device pin, out along the board routing, and ending at the signal destination. As with command-line invocation, specifying the output directory is optional. Any illegal characters used in file names are converted automatically to underscores. A default board description is included, and a default simulation is set up to measure rise and fall delays manuall both input and output simulations, which compensates for the double counting problem.
However, Intel recommends that you customize the board description to more accurately represent your routing and termination scheme. The sample board trace loading in the generated HSPICE model files must be replaced by your actual trace dxdesignet before you can run a correct simulation.
You must replace the example load with a load that matches the mmanual of your PCB board. This includes a trace model, termination resistors, and, for output simulations, a receiver model. The spice circuit node that represents the pin of the FPGA package is called pin. For an input simulation, you must also modify the stimulus portion of the spice file.
Design Architect Board Station XE to DxDesigner
The section of the file that must be modified is indicated in the following comment block. Replace the sample stimulus dxdseigner with a model for the device that drives the FPGA. To run the simulation, click Simulate. The status of the simulation is displayed in the window and saved in an.
These measurements are found in the. For output simulations, these values are already adjusted for the double count. Other values found in the. These values are not necessary for further analysis. The AvanWaves viewer opens and displays the Results Browser.
The Results Browser lets you select mannual waveform to view quickly in the main viewing window. If multiple simulations are run on the same signal, the list at the top of the Results Browser displays the results of each simulation. Click the simulation description mnaual select which simulation to dsdesigner. By default, the descriptions are derived from the first line of the HSPICE file, so the description might appear as a line of asterisks.
Select the type of waveform to view, by performing the following steps:. After making these changes, regenerate the HSPICE files if necessary, and rerun the simulation to verify whether your kanual solved the problem. This block has two main components: Although these settings are not relevant to an input buffer, they are provided to allow the SPICE deck to be modifiable to support bidirectional simulations. The SPICE decks are preconfigured to calculate the slow process corner delay but can also be used to simulate the fast process corner as well.
The fast corner conditions are listed in the header under the notes section. The final section of the header comment lists fxdesigner warning messages that you must consider when you use the SPICE decks. To perform process, voltage, and temperature PVT simulations, manually modify the manuao decks in a two step process:. Refer to the Settings dialog box options, the Fitter report, and Messages window when creating and reviewing your PCB schematic. You can use the Device dialog dxvesigner to specify general project-wide options, including specific device and pin options, which help you to implement correct board-level connections in your PCB schematic.
The Device dialog box provides project-specific device information, including the target device and any migration devices you specify.
If you want to use vertical migration, which allows you to use different devices with the same package, you can specify your list of migration devices in the Migration Devices dialog box. You must ensure that these pins are connected to the appropriate plane on the PCB.
If you are migrating from a smaller device with NC no-connect pins to a larger device with power or ground pins in the same package, you can safely connect the NC pins to power or ground pins to facilitate successful migration.
Intel Quartus Prime Pro Edition User Guide: PCB Design Tools
You can set device and pin options and verify important design-specific data in the Device and Pin Options dialog box, including options found on the GeneralConfigurationUnused PinDual-Purpose Pinsand Voltage pages. The Reserve all unused pins list shows available unused pin state options for the target device.
The dxdeeigner state for each pin is the recommended setting for each device family. When you reserve a pin as output driving ground, the Fitter connects a ground signal to the output pin internally. You should connect the output pin to the ground plane on your PCB, although you are not required to do so. Connecting the output driving ground to the ground plane is known as creating a virtual ground pin, which helps to minimize simultaneous switching noise SSN and ground bounce effects.
The Dual-Purpose Pins page specifies how configuration pins should be used after device configuration completes. You can set the function of the dual-purpose pins by selecting a value for a specific pin in the Dual-purpose pins list.
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