Stateflow

Specifying Fixed-Point Data in Stateflow

You can specify fixed-point data in Stateflow as follows:

1. Add data to Stateflow as described in Adding Data to the Data Dictionary.
2. Set the properties for the data in the data properties dialog as described in Setting Data Properties. For fixed-point data, set the following fields:
• In the Type field, select fixpt.

• This enables the Fixed-Point field Stored Integer and optional fields Fractional length and Scaling directly below the Type field.

• In the Stored Integer field, select the desired integer type to hold .

• Choose between the unsigned integer types uint8, uint16, and uint32, and the signed integer types int8, int16, int32.

• If you want radix-point-only scaling for the fixed-point data, select the optional Fraction length field. Enter an integer value for the fraction length in the field to the right. A positive value moves the radix point left of the rightmost bit by that amount. A negative value moves the radix point further right of the rightmost bit by that amount.
• If you want to enter separate slope and bias values, select the Scaling option. In the field to the right, enter a two-element array, that is, [s b], in which the first element, s, is the slope, and the second element, b, is the bias. The slope must be greater than zero.

• For example, to specify the fixed-point data , enter the slope and bias as [2.4 3.4]in the Scale field. You can also enter the slope or bias as an arithmetic expression such as [1.2*-2^1 3.4].

Note    Values that you enter for Fraction length or Scaling that exceed the ranges specified in the previous sections are flagged immediately with red text.

You can also specify a fixed-point constant indirectly in action language by using a fixed-point context-sensitive constant. See Fixed-Point Context-Sensitive Constants.

How Stateflow Implements Fixed-Point Data

Tips and Tricks for Using Fixed-Point Data in Stateflow