Version 2.1 (R2007b) Filter Design HDL Coder™ Software Release Notes

Version 2.1 (R2007b) Filter Design HDL Coder™ Software

This table summarizes what's new in Version 2.1 (R2007b).

New features and changes introduced in this version are:

• Storage of FIR Filter Coefficients in RAM or Register File

• Generate M-file Option Captures GUI Settings to Generated M-file

• Fixed-point Round Mode Supported for HDL Code Generation

• New Code Generation Properties Supported

• Default Hardware Target for Synthesis Scripts Updated to Virtex-4

• Summary of GUI Enhancements and Revisions

Storage of FIR Filter Coefficients in RAM or Register File

In previous releases, the coder obtained filter coefficients from the filter object and directly coded them into the generated code. An HDL filter realization generated for a particular set of coefficients could not be used with a different set of coefficients.

For direct-form FIR filters, the coder now provides two command-line properties that let you generate a RAM or register file interface for loading coefficients, and test the interface. These properties are:

• CoefficientSource: This property specifies whether coefficients are directly coded, or stored in RAM or register file.

• TestbenchCoeffStimulus: This property specifies how the test bench tests the generated RAM or register file interface and the performance of the filter.

See Specifying Storage of FIR Filter Coefficients in RAM or Register File for a detailed description of this feature.

Generate M-file Option Captures GUI Settings to Generated M-file

The new Generate M-file option of the Generate HDL dialog box makes command-line scripting of HDL filter code and test bench generation easier. The following figure shows the new option.

By default, Generate M-file is cleared.

When you select Generate M-file and generate code, the coder captures all nondefault HDL code and test bench generation settings from the GUI and writes out an M-file that you can use to regenerate HDL code for the filter.

For detailed information, see Capturing Code Generation Settings to an M-File.

Fixed-point Round Mode Supported for HDL Code Generation

The coder now supports the fixed-point Round rounding mode for HDL code generation. This rounding mode behaves identically to the MATLAB^® round function.

Compatibility Considerations

In previous releases, the coder did not support this rounding behavior in generated HDL code. When generating code from a filter that had the RoundMode property set to Round, the coder used nearest rounding mode instead. (See Rounding Behavior in Generated HDL Code for a detailed description of the rounding behavior in previous releases.)

If you have scripts or other programs that generate HDL code from filter objects that have the RoundMode property set to Round, the behavior of your generated HDL filters may differ from results obtained from previous releases. You may want to update your scripts accordingly.

New Code Generation Properties Supported

The coder supports two new code generation properties:

• InstancePrefix: This property specifies a string to be prefixed to component instance names in generated code. The default string is u_.

• VectorPrefix: This property specifies a string to be prefixed to vector names in generated VHDL code. The default string is vector_of_.

  Note   VectorPrefix is supported only for VHDL code generation

You can view and edit these new properties via the Instance prefix and Vector prefix edit fields on the General pane of the More HDL Settings dialog box, shown in the following figure.

See also:

• Setting a Prefix for Component Instance Names

• Setting a Prefix for Vector Names

Default Hardware Target for Synthesis Scripts Updated to Virtex-4

The default hardware target string in generated synthesis scripts now specifies:

• technology option: VIRTEX4

  In previous releases, this option defaulted to VIRTEX2.

• part option: XC4VSX35

  In previous releases, this option defaulted to XC2V500.

These updates affect the default value for the HDLSynthTerm property. The default is:

 ['set_option -technology VIRTEX4\n',...
 'set_option -part XC4VSX35\n',...
 'set_option -synthesis_onoff_pragma 0\n',...
 'set_option -frequency auto\n',...
 'project -run synthesis\n']

The default value for the HDLSynthTerm property appears in the Synthesis termination field of the EDA Tool Scripts dialog box, as shown in the following figure.

See also Generating Scripts for EDA Tools.

Compatibility Considerations

If you have existing code that generates synthesis scripts using the previous defaults for technology or part, you may want to update your code and regenerate synthesis scripts.

Summary of GUI Enhancements and Revisions

For Version 2.1, revisions and enhancements have been made to the Filter Design HDL Coder™ GUI.

Generate HDL Dialog Box

The following figure shows the Generate HDL dialog box. Revisions and enhancements to this dialog box include:

• The new Generate M-file option. When you select this option, the code generator captures all nondefault HDL code and test bench generation settings from the GUI and writes out an M-file that you can use to reconstruct the filter and regenerate HDL code. See Generate M-file Option Captures GUI Settings to Generated M-file for details.

• The EDA Tool Scripts button and the Generate M-file option are grouped together in a new Script settings section.

More HDL Settings Dialog Box

The General pane of the More HDL Settings dialog box supports the new Instance prefix and Vector prefix properties, as shown in the following figure. See New Code Generation Properties Supported for details.

EDA Tool Scripts Dialog Box

In the EDA Tool Scripts dialog box, the default value for the Synthesis termination field has changed (see Default Hardware Target for Synthesis Scripts Updated to Virtex-4 ) as shown in the following figure.

Version 2.2 (R2008a) Filter Design HDL Coder™ Software

Version 2.0 (R2007a) Filter Design HDL Coder™ Software