Apply the c2000lib Blockset

Introduction

This section uses an example to show how to create a Simulink^® model that uses C2000™ Microcontroller Blockset blocks to target your board. The example creates a model that performs PWM duty cycle control via pulse width change. It uses the C2812 ADC block to sample an analog voltage and the C2812 PWM block to generate a pulse waveform. The analog voltage controls the duty cycle of the PWM and you can observe the duty cycle change on the oscilloscope.

Hardware Setup

The following hardware is required for this example:

• Spectrum Digital eZdsp F2812

• Function generator

• Oscilloscope and probes

To connect the target hardware:

1. Connect the function generator output to the ADC input ADCINA0 on the eZdsp F2812.

2. Connect the output of PWM1 on the eZdsp F2812 to the analog input of the oscilloscope.

3. Connect VREFLO to AGND on the eZdsp F2812. See the section on the Analog Interface in Chapter 2 of the eZdsp™ F2812 Technical Reference.

Starting the c2000lib Library

At the MATLAB^® prompt, type the following command:

c2000lib

This command opens the c2000lib library blockset, which contains libraries of blocks designed for targeting your board.

Setting Up the Model

Preliminary tasks for setting up a new model include configuring your model for the target hardware and setting the simulation parameters.

To configure your model with ert.tlc system target file:

1. In the Simulink Editor of your model, select Simulation > Model Configuration Parameters > Hardware Implementation.

2. Select a TI C2000 Hardware board. The Texas Instruments Code Composer Studio (c2000) option automatically gets selected for Toolchain.

   The following default settings in the Simulation > Model Configuration Parameters dialog box appear when you select your C2000 hardware board.

   Pane	Field	Setting
   Solver	Type	Fixed-step
   Solver	Solver	discrete (no continuous states)
   Solver	Higher priority value indicates higher task priority	Value is 'off' and the parameter is disabled
   Code Generation > Optimization	Remove internal data zero initialization	Value is 'off' and the parameter is disabled
   Code Generation > Optimization	Maximum stack size (bytes)	512 (MAU)
   Hardware Implementation	Device vendor	Texas Instruments
   Hardware Implementation	Device type	C2000
   Hardware Implementation	Support long long	Selected by default
   Code Generation > Interface	Code replacement library	TI C28x

3. Click Apply.

Note

The generated code does not honor Simulink ‘stop time’ from the simulation. The ‘stop time’ is interpreted as inf. To implement a stop in the generated code, you must put a Stop Simulation block in your model.

Adding Blocks to the Model

1. Open or double-click the C281x library, c281xlib.

2. Drag the ADC block into your model. Double-click the ADC block in the model and set Sample time to 64/80000.

3. Drag the PWM block into your model. Double-click the PWM block in the model and set the following parameters.

   Pane	Field	Parameter
   Timer	Module	A
   	Waveform period source	Specify via dialog
   	Waveform period units	Clock cycles
   	Waveform period	64000
   	Waveform type	Asymmetric
   Outputs	Enable PWM1/PWM2	Selected
   	Duty cycle source	Input port
   Logic	PWM1 control logic	Active high
   	PWM2 control logic	Active low
   Deadband	Use deadband for PWM1/PWM2	Selected
   	Deadband prescaler	16
   	Deadband period	12
   ADC Control	ADC start event	Period interrupt

4. Enter simulink in the MATLAB Command Window to open the Simulink Library browser. Drag a Gain block from the Math Operations library into your model. Double-click the Gain block in the model and set the following parameters in the Function Block Parameters dialog box. Click OK.

   Pane	Field	Parameter
   Main	Gain	30
   	Multiplication	Element-wise(K.*u)
   	Sample time	-1
   Signal Attributes	Output data type mode	uint(16)
   	Integer rounding mode	Floor
   Parameter Attributes	Parameter data type mode	Inherit from input

5. Connect the ADC block to the Gain block and the Gain block to the PWM block.

   

Generating Code from the Model

This section summarizes how to generate code from your real-time model.

There are three ways to start the automatic code generation process:

• In the Simulink Editor, click Build Model or Deploy to Hardware.

• On your model, press Ctrl+B.

• Press the Build button on the Code Generation pane of the Configuration Parameters dialog box.