Simulink® Fixed Point™ 5.6

Product Description

• Introduction and Key Features
• Working with Simulink Fixed Point
• Generating and Deploying Production Code

Working with Simulink Fixed Point

Using Simulink Fixed Point, you can turn a floating-point design built in Simulink, Stateflow, the Signal Processing Blockset, and the Video and Image Processing Blockset into a fixed-point design without changing any blocks in your model. You can easily benchmark the final fixed-point implementation against the floating-point design and generate fixed-point C code that targets fixed-point processors.

Modeling Fixed-Point Designs

Simulink Fixed Point enables you to specify all the fixed-point data type properties of your design, including the number of bits, whether it is signed or unsigned, and its scaling. You can then instrument your model with fixed-point information. For example, word sizes from 1 to 128 bits are supported, and scaling can be controlled either by binary point location or sensor data scaling. You can control the details of the math, such as how rounding and overflow will be dealt with. For blocks from the Signal Processing Blockset and Video and Image Processing Blockset, you can also control accumulator and product register sizes.



A 10-bit receiver for an ultra wideband wireless communications system, modeled in Simulink and the Signal Processing blockset. Simulink Fixed Point enables fixed-point simulation to study the effects of limited range and precision on the receiver’s performance. Click on image to see enlarged view.

Simulating Fixed-Point Designs

Once a model has been instrumented with fixed-point data types, you can simulate its performance to explore design implementation tradeoffs between limited range and precision for fixed-point embedded systems.

The debugging capabilities of Simulink Fixed Point let you quickly switch to a floating-point representation of your model to perform benchmarking of the design, identify modeling errors, and determine ideal minimum, maximum, and overflow values.

Using an automatic scaling script, you can access these values and change the scaling of signals, optimizing precision while ensuring that their simulation range is covered. If the output data type is a generalized fixed-point number, you can lock the output scaling. Otherwise, scaling is optimized automatically.

Sharing Models with Fixed-Point Data Types

Simulink Fixed Point makes it easy to share Simulink and Stateflow models that include fixed-point data types. Because data types can be globally overridden, you can switch between fixed-point and floating-point representations without changing the model’s structure. The model remains compatible with Simulink, Stateflow and the Signal Processing Blockset. As a result, you can use one model throughout your design process. You can keep models in sync, reuse the same models for multiple purposes, and circle back in the development process without breaking the model.



The Fixed-Point Settings GUI provides convenient access to global data type override, logged min/max and overflow values, automatic scaling, and comparison of floating-point to fixed-point signal responses. Click on image to see enlarged view.