Objective

The objective of this tutorial is to explore an easy way to write visually logic code for the CrcDuino
that repeats the loop() part of the code as fast as possible (scan time minimization), all while
allowing to perform actions in a sequential, orderly and predictable manner.

2 coding methods are shown. Both accomplish the same thing, using the same wiring.

Using IF statements: the easiest, most visual way to go for beginners.
Using a Switch-Case statement: a more compact and efficient way to go, to use once you’re comfortable with the why’s and how’s of the IF statement method.

Tutorial 11 gives a walkthrough of a similar program structure.

Wiring schematics and complete presentation

Code - Using IF statements

Download the Arduino IDE .ino file:

This is a transcript of the code:

//***************************************************************************
// CrcDuino Tutorial05.1 - example of a sequential program structure for autonomous robots; using if statements
//NOTE: In contrary to the other tutorials, the Normally Closed contact of the buttons and limit switch is used here.
//      This means that, when the button or switch is not press, "LOW" will be read since an electrical continuity to GND
//      is established. When they are pressed, the pin will therefore read "HIGH".
//      Why do we do that here, instead of the method using the NO contact? Just to show you that all paths lead to Rome :)
//***************************************************************************
#include <CrcLib.h>

//Renaming pins with significant names
#define NEXT_STEP_ODD CRC_DIG_1
#define NEXT_STEP_EVEN CRC_DIG_2

//Variable declaration
//Step management variables
bool stepSleep = LOW;
bool step1 = LOW;
bool step2 = LOW;
bool step3 = LOW;

//***************************************************************************

void setup() {
  CrcLib::Initialize();
  
  Serial.begin(2000000);  //Start the Serial Monitor communication for on computer screen display, at a high baud rate for faster code execution

  CrcLib::SetDigitalPinMode(NEXT_STEP_ODD,INPUT); //Digital ports need to be tell wether they are used as inputs or outputs
  CrcLib::SetDigitalPinMode(NEXT_STEP_EVEN,INPUT);
  
  //We want to be in sleep mode upon startup
  stepSleep = HIGH; step1 = LOW; step2 = LOW; step3 = LOW;
  
}

//***************************************************************************

void loop() {
  CrcLib::Update();
  //We continuously want to print on serial monitor the state of our program (what step it's in)
  //So we will print at every program scan ( a scan being an exectuion of "loop()"
  //Remember: LOW means "0", and HIGH means "anything but "0"
  Serial.print("stepSleep: "); Serial.print(stepSleep);
  Serial.print(" step1: "); Serial.print(step1);
  Serial.print(" step2: "); Serial.print(step2);
  Serial.print(" step3: "); Serial.print(step3);
  Serial.print(" scan time: "); Serial.println( CrcLib::GetDeltaTimeMicros() ); //Print the value returned by GetDeltaTime, which is the scan time 

//------------------
  if(stepSleep)
  {

    //The code you'd want to execute during stepSleep would go here

    //When the step exiting condition is met (we press the button/switch and the other one is not pressed)...
    if( CrcLib::GetDigitalInput(NEXT_STEP_ODD) == HIGH && CrcLib::GetDigitalInput(NEXT_STEP_EVEN) == LOW)  
    {
      //...we change the steps configuration to take another branch ( if() statement ) during the next scans
      stepSleep = LOW; step1 = HIGH; step2 = LOW; step3 = LOW;
    }
  }
//------------------
  if(step1)
  {

    //The code you'd want to execute during step1 would go here

    //When the step exiting condition is met (we press the button/switch and the other one is not pressed)...
    if( CrcLib::GetDigitalInput(NEXT_STEP_EVEN) == HIGH && CrcLib::GetDigitalInput(NEXT_STEP_ODD) == LOW )
    {
      //...we change the steps configuration to take another branch ( if() statement ) during the next scans
      stepSleep = LOW; step1 = LOW; step2 = HIGH; step3 = LOW;
    }  
  }
//------------------
  if(step2)
  {
    //The code you'd want to execute during step2 would go here

    //When the step exiting condition is met (we press the button/switch and the other one is not pressed)...
    if( CrcLib::GetDigitalInput(NEXT_STEP_ODD) && CrcLib::GetDigitalInput(NEXT_STEP_EVEN) == LOW )
    {
      stepSleep = LOW; step1 = LOW; step2 = LOW; step3 = HIGH;
    }
  }
//------------------
  if(step3)
  {
    //The code you'd want to execute during step3 would go here

    //When the step exiting condition is met (we press the button/switch and the other one is not pressed)...
    if( CrcLib::GetDigitalInput(NEXT_STEP_EVEN) == HIGH && CrcLib::GetDigitalInput(NEXT_STEP_ODD) == LOW )
    {
      //...we change the steps configuration to take another branch ( if() statement ) during the next scans
      stepSleep = HIGH; step1 = LOW; step2 = LOW; step3 = LOW;
    }
  }
//------------------
}

Code - Using a Switch-Case statement

Download the Arduino IDE .ino file:

This is a transcript of the code:

//***************************************************************************
// CrcDuino Tutorial05.2 - example of a sequential program structure for autonomous robots; using a Switch-Case statement
//NOTE: In contrary to the other tutorials, the Normally Closed contact of the buttons and limit switch is used here.
//      This means that, when the button or switch is not press, "LOW" will be read since an electrical continuity to GND
//      is established. When they are pressed, the pin will therefore read "HIGH".
//      Why do we do that here, instead of the method using the NO contact? Just to show you that all paths lead to Rome :)
//***************************************************************************
#include <CrcLib.h>

//Renaming pins with significant names
#define NEXT_STEP_ODD CRC_DIG_1
#define NEXT_STEP_EVEN CRC_DIG_2

using namespace Crc;

int currentStep = 0; //Step management variable
//***************************************************************************
void setup() {
  CrcLib::Initialize();
  
  Serial.begin(2000000);  //Start the Serial Monitor communication for on computer screen display, at a high baud rate for faster code execution

  CrcLib::SetDigitalPinMode(NEXT_STEP_ODD,INPUT); //Digital ports need to be tell wether they are used as inputs or outputs
  CrcLib::SetDigitalPinMode(NEXT_STEP_EVEN,INPUT);
  
  currentStep = 0; //We want to be in sleep mode upon startup
  
}
//***************************************************************************
void loop() {
  CrcLib::Update();
  //We continuously want to print on serial monitor the state of our program (what step it's in)
  //So we will print at every program scan ( a scan being an exectuion of "loop()"
  //Remember: LOW means "0", and HIGH means "anything but "0"
  Serial.print("Step currently executed "); Serial.print(currentStep);
  Serial.print(" scan time: "); Serial.println( CrcLib::GetDeltaTimeMicros() ); //Print the value returned by GetDeltaTime, which is the scan time 

  switch(currentStep)
  {
//------------------
    case 0:
    
      //The code you'd want to execute during Step0 would go here
      
      if( CrcLib::GetDigitalInput(NEXT_STEP_ODD) == HIGH && CrcLib::GetDigitalInput(NEXT_STEP_EVEN) == LOW)  
      {
        currentStep = 1;
      }
      break;
//------------------
    case 1:
    
      //The code you'd want to execute during Step1 would go here
  
      if( CrcLib::GetDigitalInput(NEXT_STEP_EVEN) == HIGH && CrcLib::GetDigitalInput(NEXT_STEP_ODD) == LOW )
      {
        currentStep = 2;
      }  
      break;
//------------------
    case 2:
    
      //The code you'd want to execute during Step2 would go here
  
      if( CrcLib::GetDigitalInput(NEXT_STEP_ODD) == HIGH && CrcLib::GetDigitalInput(NEXT_STEP_EVEN) == LOW )
      {
        currentStep = 3;
      }
      break;
//------------------
    case 3:
    
      //The code you'd want to execute during Step3 would go here
  
      if( CrcLib::GetDigitalInput(NEXT_STEP_EVEN) == HIGH && CrcLib::GetDigitalInput(NEXT_STEP_ODD) == LOW )
      {
        currentStep = 0;
      }  
      break;
//------------------
  }
}

Système CrcDuino System

Tutorial 05 - Sequential program structure

Analytics

Objective

Wiring schematics and complete presentation

Code - Using IF statements

Code - Using a Switch-Case statement

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