I am officially lost with S-Function builder

I was trying to make a simulink S-Function to connect Arduino and it Sensor Adafruit INA219 to simulink, I needed to add the library for the INA219. However it is been frustrating to understand how to do it using matlab. I tried many different sources to understand.

I would appreciate if someone could explain me step by step this procedure.

The wrapper, and the errors:

    /*
     * Include Files
     *
     */
    #if defined(MATLAB_MEX_FILE)
    #include "tmwtypes.h"
    #include "simstruc_types.h"
    #else
    #include "rtwtypes.h"
    #endif

    /* %%%-SFUNWIZ_wrapper_includes_Changes_BEGIN --- EDIT HERE TO _END */
    #ifndef MATLAB_MEX_FILE
    #define ARDUINO 100
    #include <math.h>
    #include <Arduino.h>
    #include <Wire.h>
    #include <Adafruit_INA219.h>
    #include <Adafruit_INA219.cpp>

    #endif
    /* %%%-SFUNWIZ_wrapper_includes_Changes_END --- EDIT HERE TO _BEGIN */
    #define y_width 1

    /*
     * Create external references here.  
     *
     */
    /* %%%-SFUNWIZ_wrapper_externs_Changes_BEGIN --- EDIT HERE TO _END */
    /* extern double func(double a); */
    /* %%%-SFUNWIZ_wrapper_externs_Changes_END --- EDIT HERE TO _BEGIN */

    /*
     * Output functions
     *
     */
    extern "C" void INA219_Outputs_wrapper(uint32_T *busvoltage,
          uint32_T *shuntvoltage,
          uint32_T *loadvoltage,
          uint32_T *current_mA,
          uint32_T *power_mW,
          const real_T *xD)
    {
    /* %%%-SFUNWIZ_wrapper_Outputs_Changes_BEGIN --- EDIT HERE TO _END */
    /* This sample sets the output equal to the input
          y0[0] = u0[0]; 
     For complex signals use: y0[0].re = u0[0].re; 
          y0[0].im = u0[0].im;
          y1[0].re = u1[0].re;
          y1[0].im = u1[0].im;
     */
    #ifdef MATLAB_MEX_FILE
    /* 
      float shuntvoltage = 0;
      float busvoltage = 0;
      float current_mA = 0;
      float loadvoltage = 0;
      float power_mW = 0; 
     */

      shuntvoltage = ina219.getShuntVoltage_mV();
      busvoltage = ina219.getBusVoltage_V();
      current_mA = ina219.getCurrent_mA();
      power_mW = ina219.getPower_mW();
      loadvoltage = busvoltage + (shuntvoltage / 1000);

    #endif
    /* %%%-SFUNWIZ_wrapper_Outputs_Changes_END --- EDIT HERE TO _BEGIN */
    }

    /*
     * Updates function
     *
     */
    void INA219_Update_wrapper(uint32_T *busvoltage,
          uint32_T *shuntvoltage,
          uint32_T *loadvoltage,
          uint32_T *current_mA,
          uint32_T *power_mW,
          real_T *xD)
    {
    /* %%%-SFUNWIZ_wrapper_Update_Changes_BEGIN --- EDIT HERE TO _END */
    /*
     * Code example
     *   xD[0] = u0[0];
     */

    #ifdef MATLAB_MEX_FILE
    Adafruit_INA219 ina219;
    ina219.begin();
    ina219.setCalibration_16V_400mA();

    #endif
    /* %%%-SFUNWIZ_wrapper_Update_Changes_END --- EDIT HERE TO _BEGIN */
    }

   S-function Builder  1 Clear
        10:21 PM Elapsed: 0.42 sec
        INA219_wrapper.c
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(65): error C2065: 'ina219': undeclared identifier
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(65): error C2224: left of '.getShuntVoltage_mV' must have struct/union type
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(66): error C2065: 'ina219': undeclared identifier
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(66): error C2224: left of '.getBusVoltage_V' must have struct/union type
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(67): error C2065: 'ina219': undeclared identifier
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(67): error C2224: left of '.getCurrent_mA' must have struct/union type
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(68): error C2065: 'ina219': undeclared identifier
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(68): error C2224: left of '.getPower_mW' must have struct/union type
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(69): error C2296: '/': illegal, left operand has type 'uint32_T *'
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(93): error C2065: 'Adafruit_INA219': undeclared identifier
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(93): error C2146: syntax error: missing ';' before identifier 'ina219'
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(93): error C2065: 'ina219': undeclared identifier
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(94): error C2065: 'ina219': undeclared identifier
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(94): error C2224: left of '.begin' must have struct/union type
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(95): error C2065: 'ina219': undeclared identifier
        D:\1 - Main\UWF\Office of Undergraduate Research (OUR)\SURP\SURP 2018\MATLAB\INA219\INA219_wrapper.c(95): error C2224: left of '.setCalibration_16V_400mA' must have struct/union type
        Component:S-function Builder | Category:Build error

Answer 1

[Madhu Govindarajan]

The S-function builder approach is quite old and a little difficult, however if you are really set on using that here is a video that I found quite helpful - https://www.youtube.com/watch?v=_OLctOFjjYQ

The recommended approach by MathWorks for the same is to use the System Objects workflow. Here is a detailed documentation on how to build custom support using this workflow - https://www.mathworks.com/help/supportpkg/arduino/device-driver-blocks.html

I have also found this video to be helpful for the recommended workflow - https://www.mathworks.com/videos/creating-a-simulink-block-using-matlab-code-98734.html