Waijung 2 User Guide

How this block appears in a Simulink model?

What can be configured?

INPUT/ OUTPUT Port

When to use this block?

When you want to add your own custom asynchronous (interrupt) C code to the system.

How does this block work?

This block can be used when you want to add your own custom C code to the system. To use the IRQ Custom Code Block you need to complete the following steps.

oStep 1: Define include and source files for the custom code.

Use File path edit box to define the path where the files are located. Only one path can be entered and therefore, it is assumed that all files are located in the same folder. A user could either specify the relative path or the absolute path. Every component of the path should be comma separated and enclosed with double-quotes except Matlab built in methods such as pwd.

 For example: a) pwd,”..”,”srcfolder”

                 b) “C:”,“Users”,”admin”,”Downloads”,”srcfolder”

                 c) “C:\Users\admin”,”Downloads”,”srcfolder”        

Use File names edit box to define the files that needs to be included in the build process. Waijung 2 will automatically copy these files to the build directory during the build process. Any number of files can be specified. Each file name has to be comma separated.

oStep 2: Define three-function prototypes: initial, enable, disable.

When generating code for a Simulink block, Matlab creates these three different functions.

▪Initial function

An initial function will be called once at MCU start-up.

▪Enable function

An enable function will be called at system initialization and every time the block is enabled, e.g. in a case where a block is located in an Enabled Subsystem.

▪Disable function

A disable function will be called at system termination and every time the block is disabled, e.g. in a case where a block is located in an Enabled Subsystem.

Your job is to define functions that will be wrapped inside these automatically-generated MATLAB function calls. The function definitions of the prototypes specified are to be found in the included source and header files. Apart from the main function prototype, additional C code lines can also be specified, if necessary, in each of the edit box spaces mentioned below.

▪The Initial function can be defined in the Initial function call string edit box. The Initial function must not have any input parameters or a return value.

▪The Enable function can be defined in the Enable function call string edit box.

▪The Disable function can be defined in the Disable function call string edit box.

▪The Enable function and Disable function must not have any input parameters or return values. These functions will be called every time the system is initialized and enabled/disabled.

oStep 3: Define the IRQ function prototype without the semicolon.

This parameter can be used to define the function prototype of the ISR function. This enables the user to specify any input parameters for the ISR.

 

When designing the custom C library, it is important to add the header rtwtypes.h where the Matlab typedefs are defined. These typedefs must be used when developing the custom C library functions.  

 

Demo

Demo file : esp32_irq_customcode_demo.slx

Description

This example shows how to use the IRQ Custom Code Block on ESP32 by implementing a timer interrupt. To observe the interrupt, a GPIO is toggled within the interrupt service routine.

Setup

First, download the irq_customcode_demo_lib.zip and extract the content. Copy the extracted folder to the same folder as the model file. Open the model file from Matlab. In the IRQ Custom Code block mask, browse the Path for include files (*.h) and Path for source files (*.c) to the extracted folder.

An oscilloscope should be connected to the GPIO pin specified in the model (in the example GPIO Pin 2 is selected.)

What should be happening?

After the model file is compiled and uploaded to the ESP32 board, the following output can be seen on the oscilloscope.