More interrupt questions.

Projects Programming
1

I previously posted a question about interrupts, and since managed to get them working. However, I am getting some weird behaviour.

When I press the button, the program doesn't seem to go back to the loop, rather the screen goes blank. The interrupt still works, as if I put a serial output in it, it shows that it is being pressed, but it doesn't seem to go back to the program.

The code is below:

float Version = 0.7;

//Settings
int pulsesPerRev = 4;
int pulsesPerRot = 6;
/*Wheel circumference in metres*/
double wheelCircumference = 1.5;

//Libraries
#include <EEPROM.h>
#include <LiquidCrystal.h>

//LCD Pins
int rs = 32;
int enable = 33;
int d4 = 34;
int d5 = 35;
int d6 = 36;
int d7 = 37;

//LCD Initialisation
LiquidCrystal lcd(rs,enable,d4,d5,d6,d7);

//Pins
//Digital
int RPMPin = 41;
//Analog
int lambdaPin= 0;
int Temp1Pin = 1;
int Temp2Pin = 2;
//Interrupts
/*The line from the speedometer should be attached to digital 2.
  The line from button 1 should be attached to digital 3.
  The line from button 2 should be attached to digital 21. */

//Variables to be loaded from EEPROM
int setting = 0;
int imperialMetric = 0;
/* The total distance travelled in m. */
double TotalDistance = 0;

//External Variables
int numberOfSettings = 2;
int newDisplay = 456;
double speed;
volatile int numPulses = 0;
volatile unsigned long pulseDebounce;
volatile unsigned long buttonDebounce;
unsigned long lastSpeedTime;
int rpmSample = 1000;



void setup(){
  //Start LCD
  lcd.begin(16,2);
  //Setup interrupts.
  attachInterrupt(0,pulse,RISING);
  attachInterrupt(1,button1Press,FALLING);
  attachInterrupt(2,button2Press,FALLING);
  //Display startup on LCD
  lcd.print("Speeduino");
  lcd.setCursor(0,1);
  lcd.print("Version ");
  lcd.print(Version);
  delay(2000);
  lcd.clear();
  pinMode(RPMPin,INPUT);
}
void loop(){
  unsigned long timer;
  if (setting == 0) displayODO();
  if (setting == 1) displayRPM();
  
  if (millis() > timer + 1500){
    updateSpeedDist();
    timer = millis();
  }
}
void pulse(){
  if (millis()> pulseDebounce + 100) {
    numPulses++;
    pulseDebounce = millis();
  }
}
void button1Press(){
  if (millis()>buttonDebounce+100) {
    setting++;
    setting = setting % (numberOfSettings);
    buttonDebounce = millis();
  }
}
void button2Press(){
  if (millis()>buttonDebounce+100) {
    imperialMetric++;
    imperialMetric = imperialMetric % 2;
    buttonDebounce = millis();
    newDisplay = 897;
  }
}
void updateSpeedDist(){
  unsigned long newSpeedTime = millis();
  double speedMps = (((double)numPulses/(double)pulsesPerRot)*wheelCircumference)/(((double)newSpeedTime - (double)lastSpeedTime)/1000);
  speed = speedMps * 2.23693629;
  
  double newDist = (((double) numPulses/(double)pulsesPerRot)*wheelCircumference);
  TotalDistance = newDist + TotalDistance;
  numPulses = 0;
}
int getRPM(){
  unsigned long time = millis();
  int voltage = 1;
  int previousRead = 0;
  int newtime = millis();
  int revCount = 0;
  
  while (newtime < time + rpmSample){
    voltage = digitalRead(RPMPin);
    if ((voltage==HIGH)&&(previousRead==0)) {
      revCount++;
      previousRead = 1;
    }
    else if (voltage == LOW){
      previousRead = 0;
    }
  }
  return (int)((((double)revCount/(double)((double)rpmSample/1000))*60)/(double)pulsesPerRev);
}
void displayODO(){
  if (newDisplay != 0){
    lcd.clear();
    newDisplay = 0;
  }
  lcd.setCursor(0,0);
  if (imperialMetric == 0){
    lcd.print("Speed: ");
    lcd.print(speed);
    lcd.print("mph");
    lcd.setCursor(0,1);
    lcd.print("Dist: ");
    lcd.print((TotalDistance*0.000621371192));
    lcd.print("M");
  }
  if (imperialMetric == 1){
    lcd.print("Speed: ");
    lcd.print(speed*1.609344);
    lcd.print("kph");
    lcd.setCursor(0,1);
    lcd.print("Dist: ");
    lcd.print(TotalDistance*0.0001);;
    lcd.print("km");
  }
}
void displayRPM(){
  if (newDisplay != 1){
    lcd.clear();
    newDisplay = 1;
  }
  int rpm = getRPM();
  lcd.setCursor(0,0);
  if (imperialMetric == 0){
    lcd.print("Speed: ");
    lcd.print(speed);
    lcd.print("mph");
    lcd.setCursor(0,1);
    lcd.print("RPM: ");
    lcd.print(rpm);
  }
  if (imperialMetric == 1){
    lcd.print("Speed: ");
    lcd.print(speed*1.609344);
    lcd.print("kph");
    lcd.setCursor(0,1);
    lcd.print("RPM: ");
    lcd.print(rpm);
  }
}

I only have button 1 connected at the moment, but I don't see why that would make any difference.

Thanks :slight_smile:

2

You have some of your variables that are shared between interrupt and main program declared as 'volatile', which is correct. But shouldn't 'setting' and 'imperialMetric' also be declared 'volatile'?

3

Yes, but that doesn't seem to be the problem having fixed that. Writing a simpler program, I can get the button to work as expected, so it isn't the board. Am I doing something stupid within one of the functions?

4 
attachInterrupt(0,pulse,RISING);
  attachInterrupt(1,button1Press,FALLING);
  attachInterrupt(2,button2Press,FALLING);

Any reason for not using the names that you've given these pins (and any reason those names are not constants)?

5

Umm, mainly because I had forgotten how to define constants? #define pinName x?

6

I'm sorry, I'd assumed these were your pin numbers.

int lambdaPin= 0;
int Temp1Pin = 1;
int Temp2Pin = 2;
7

They are going to be for additional sensors once I have the basics working. If I am right with the define code above, I will swap that in.

If I put a serial output in the loop, it prints until I press the button, and then it stops. Odd.

8

it prints until I press the button

Which button?

9

Reset :wink:

10

AWOL:
Which button?

Button 1.