Version 6.1 (R2009a) Simulink Fixed Point Software :: Simulink Fixed Point Release Notes (Simulink® Fixed Point™)

Version 6.1 (R2009a) Simulink Fixed Point Software

This table summarizes what's new in Version 6.1 (R2009a):

New Features and Changes	Version Compatibility Considerations	Fixed Bugs and Known Problems	Related Documentation at Web Site
Yes Details below	Yes—Details labeled as Compatibility Considerations, below. See also Summary.	Bug Reports Includes fixes	Printable Release Notes: PDF Current product documentation

New features and changes introduced in this version are

Discrete Filter Block Supports Fixed-Point Data Types

The Discrete Filter block now offers support for fixed-point and integer data types.

In this release, the following enhancements have been made to the Discrete Filter block:

Improved numerics and run-time performance of outputs and states by reducing the number of divide operations in the filter to at most one
Support for vector and matrix inputs
Support for inputs with mixed complexity
A new Initial states parameter allows you to enter nonzero initial states
A new Leading denominator coefficient equals 1 parameter provides a more efficient implementation by eliminating all divides when the leading denominator coefficient is one

Prelookup and Interpolation Using Prelookup Blocks Support Parameter Data Types That Are Different from Signal Data Types

The Prelookup block supports breakpoint data types that differ from input data types. This enhancement provides these benefits:

Enables lower memory requirement for storing breakpoint data that uses a smaller type than the input signal
Enables sharing of prescaled breakpoint data between two Prelookup blocks with different input data types
Enables sharing of custom storage breakpoint data in Real-Time Workshop generated code for blocks with different input data types

The Interpolation Using Prelookup block supports table data types that differ from output data types. This enhancement provides these benefits:

Enables lower memory requirement for storing table data that uses a smaller type than the output signal
Enables sharing of prescaled table data between two Interpolation Using Prelookup blocks with different output data types
Enables sharing of custom storage table data in Real-Time Workshop generated code for blocks with different output data types

The Interpolation Using Prelookup block also supports separate data type specification for intermediate results. This enhancement enables use of a different precision for internal computations than for table data or output data.

Lookup Table (n-D) and Interpolation Using Prelookup Blocks Perform Efficient Fixed-Point Interpolations

Whenever possible, Lookup Table (n-D) and Interpolation Using Prelookup blocks use a faster overflow-free subtraction algorithm for fixed-point interpolation. To achieve this efficiency, the blocks use a data type of larger container size to perform the overflow-free subtraction, instead of using control-flow branches as in previous releases. Also, Real-Time Workshop generated code for fixed-point interpolation is now smaller.

Compatibility Considerations

Due to the change in the overflow-free subtraction algorithm, fixed-point interpolation in Lookup Table (n-D) and Interpolation Using Prelookup blocks might, in a few cases, introduce different rounding results from previous releases. Both simulation and code generation use the new overflow-free algorithm, so they have the same rounding behavior and provide bit-true consistency.

Autoscaling for Simulink Signal Objects is Supported by Fixed-Point Advisor and Fixed-Point Tool

In this release, Fixed-Point Advisor and Fixed-Point Tool can propose new scaling for Simulink signal objects in the base or model workspace. If you accept the proposed scaling, Fixed-Point Advisor or Fixed-Point Tool will apply the new scaling to the Simulink signal objects automatically.

For more information, see Automatic Scaling Tools in the Simulink Fixed Point documentation.

Rounding Modes Convergent and Round Added to Multiple Blocks

Rounding modes Convergent and Round were added to multiple Simulink, Communications Blockset™, Signal Processing Blockset™, and Video and Image Processing Blockset™ blocks. The introduction of these rounding modes allows numerical agreement with advanced embedded hardware and MATLAB.

For more information, see Rounding Mode: Convergent and Rounding Mode: Round in the Simulink Fixed Point documentation.

Compatibility Considerations

If you use an earlier version of Simulink to open a model that uses the Convergent or Round rounding modes, the software automatically changes the rounding mode to Nearest.

Simplest Rounding Mode Added to Multiple Blocks

The Simplest rounding mode was added to multiple Simulink, Communications Blockset, Signal Processing Blockset, and Video and Image Processing Blockset blocks. Support for this rounding mode maximizes efficiency for blocks handling mixtures of floating point and fixed point.

For more information, see Rounding Mode: Simplest in the Simulink Fixed Point documentation.

Multiword Generated Code Enhancements

More Efficient Reuse of Temporary Variables

A reduction in the number of temporary variables and reorganization of function signatures provide more efficient multiword code. This results in faster execution speeds and reduced memory usage. In addition, the new code compiles faster and is easier to inspect manually.

Support for Real-Time Workshop Embedded Coder Code Control Features

More Real-Time Workshop^® Embedded Coder™ code control features now apply to multiword functions. These features provide the ability to customize your code, for example, you can customize the code style.

Fixed-Point Tool Provides the Ability to Narrow Down Displayed Results Using Filtering Controls

In this release, the Fixed-Point Tool provides a results filter in the toolbar which specifies the type of results to display. You can use the filter to focus on the types of results that you are interested in at different stages of the autoscaling workflow. Filter options include:

All results
Signal Logging results
Min/Max results
Overflows
Conflicts with proposed data types
Groups that must share the same data type

For more information, see fxptdlg in the Simulink Reference.

MinMax Block Performs More Efficient and Accurate Comparison Operations

For multiple inputs with mixed floating-point and fixed-point data types, the MinMax block selects an appropriate data type for performing comparison operations, instead of using the output data type for all comparisons, as in previous releases. This enhancement provides these benefits: