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1. 

   Darth Maker
   Member

   The button example program does not work properly. While you hold down the button, the LED oscillates off and on rapidly. I suppose it is possible that that is proper operation, it would make more sense to have the switch to the opposite state when the button is pressed.

   This is true in release 0.0.11, using a brand spanking new Maple Mini.

   This should be fixed with the simple addition of a while(isButtonPressed()); statement inside the if block. However, this does not seem to help, even with a 1ms delay added for debounce.

   Ok, I added a 10ms delay, and it seems to work properly now, except that the toggle is happening when I release the button, instead on press like it should.

   void setup() {
// Initialize the built-in LED pin as an output:
pinMode(BOARD_LED_PIN, OUTPUT);
// Initialize the built-in button (labeled BUT) as an input:
pinMode(BOARD_BUTTON_PIN, INPUT);
}

   void loop() {
   // Check if the button is pressed.
   if (isButtonPressed())
   {
   // If so, turn the LED from on to off, or from off to on:
   toggleLED();

   while(isButtonPressed());
delay(10);
}
}

   Posted 4 years ago #
2. 

   robodude666
   Member

   isButtonPressed() is simply poorly named and its functionality is therefore misleading. If you were to use Objective-C's verbose naming scheme it should be called wasButtonPressedAndThenReleased(). In other words:

   uint8 isButtonPressed() {
       if (digitalRead(BOARD_BUTTON_PIN)) {
           delay(BUTTON_DEBOUNCE_DELAY);
           while (digitalRead(BOARD_BUTTON_PIN))
               ;
           return true;
       }
       return false;
   }

   It checks to see if the button was pressed. It then waits a debounce period (1ms), and waits for the button to be released. You may want to try this function for your application:

   bool isButtonDown()
   {
       if (digitalRead(BOARD_BUTTON_PIN))
   	{
           delay(1); // 1ms debounce perioud
           return digitalRead(BOARD_BUTTON_PIN) ? true : false;
       }
       return false;
   }

   This isButtonDown() function simply checks to see if the button is down after a debounce period. With this new function, your code should work as expected:

   void loop()
   {
   
   	if(isButtonDown()) // Is the Button down?
   	{
   		toggleLED(); // Toggle the LED
   		while(isButtonDown()); // Wait for button to be released
   	}
   }

   The last while(isButtonDown()); is required or else isButtonDown() will continuously return true if the button remains down. The while statement, as you previously expected it to, waits for the button to be released. In addition, because of this new "release" check no debounce delay is required in your application itself.

   -robodude666

   Posted 4 years ago #

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