How to exit a nested if statement

Projects Programming
12

I would also use a state machine approach. Here’s a barebones outline. It include just enough stuff to compile without errors. Doesn’t include all the setup() stuff you need for your hardware, ISR, etc.

You didn’t say how your button is wired. But, if one terminal is connected to PIN 3 and the other to +5, then it’s wrong. Connect it between PIN 3 and ground and use INPUT_PULLUP when you set the pin mode. The logic will be reversed -- PIN 3 will read LOW when button is pushed. But, that’s the right way to do it.

Things you’ll need to read up on:

#include<SD.h>

enum States {initialize, logging, paused};
States currentState = initialize;

uint8_t lastButtonState;
const uint8_t button_in = 3;
volatile bool mpuInterrupt = false;
bool dmpReady = false;
File myFile;

void setup() {
  Serial.begin(57600);
  //
  // Setup your hardware, interrupts, etc. here
  //

  // Start the SD system, but don't open a file yet. Will do that in initialize state
  if(!SD.begin(4)) {
    Serial.println("SD initialization failed");
    while(1) {}
  }

  pinMode(button_in, INPUT_PULLUP);
  lastButtonState = digitalRead(button_in);

}

void loop() {
  uint8_t currentButtonState = digitalRead(button_in);

  switch (currentState) {
    case initialize:
      myFile = SD.open("Use a unique filename here every time", FILE_WRITE);
      currentState = logging;
      break;

    case logging:
      if (dmpReady) {
        mpuInterrupt = false;
        //
        // process sensor data here, log to file, print to Serial, etc.
        //
      }

      if (currentButtonState != lastButtonState) {
        if (currentButtonState == LOW) {
          currentState = paused;
          //
          // close the SD card file here, print results summary, etc.
          //
        }
      }
      break;

    case paused:
      // Don't do anything unless button is pushed again
      if (currentButtonState != lastButtonState) {
        if (currentButtonState == LOW) {
          currentState = initialize;
        }
      }
      break;

    default:
      break;
  }

  lastButtonState = currentButtonState;

  // You can do any other processing you want here because you're not stuck in a while loop waiting for an interrupt
}