Natalia Govor / Mbed OS lab2_digitalInInterrupt

Implemented interrupt code to handle presses of two buttons and control 2 leds separately.

Fork of digitalInInterrupt_sample by William Marsh

main.cpp@4:c8b84240732a, 2018-02-01 (annotated)

Committer:
natgovor
Date:
Thu Feb 01 12:30:18 2018 +0000
Revision:
4:c8b84240732a
Parent:
3:05b6a1431a6b 
Implemented interrupt code to handle presses of two buttons and control 2 leds separately.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
WilliamMarshQMUL 0:a66a8cb0012c 1 #include "mbed.h"
WilliamMarshQMUL 0:a66a8cb0012c 2
WilliamMarshQMUL 1:13e0c1956b54 3 // Labs 2: Example program for using an interrupt (or callback)
WilliamMarshQMUL 1:13e0c1956b54 4 // -----------------------------------------------------------
WilliamMarshQMUL 1:13e0c1956b54 5 // A callback function (corresponding to an ISR) is called when a button
WilliamMarshQMUL 1:13e0c1956b54 6 // is pressed
WilliamMarshQMUL 1:13e0c1956b54 7 // The callback uses a shared variable to signal another thread
WilliamMarshQMUL 0:a66a8cb0012c 8
natgovor 4:c8b84240732a 9 InterruptIn redButton(PTD0);
natgovor 4:c8b84240732a 10 InterruptIn blueButton(PTD5);
natgovor 4:c8b84240732a 11 DigitalOut redLed(LED_RED);
natgovor 4:c8b84240732a 12 DigitalOut blueLed(LED_BLUE);
WilliamMarshQMUL 0:a66a8cb0012c 13
natgovor 4:c8b84240732a 14 volatile int redPressEvent = 0;
natgovor 4:c8b84240732a 15 volatile int bluePressEvent = 0;
WilliamMarshQMUL 0:a66a8cb0012c 16
WilliamMarshQMUL 3:05b6a1431a6b 17 // This function is invoked when then interrupt occurs
WilliamMarshQMUL 3:05b6a1431a6b 18 // Signal that the button has been pressed
WilliamMarshQMUL 1:13e0c1956b54 19 // Note: bounce may occur
natgovor 4:c8b84240732a 20 void redButtonCallback(){
natgovor 4:c8b84240732a 21 redPressEvent = 1 ;
natgovor 4:c8b84240732a 22 }
natgovor 4:c8b84240732a 23
natgovor 4:c8b84240732a 24 void blueButtonCallback(){
natgovor 4:c8b84240732a 25 bluePressEvent = 1 ;
WilliamMarshQMUL 0:a66a8cb0012c 26 }
WilliamMarshQMUL 0:a66a8cb0012c 27
WilliamMarshQMUL 3:05b6a1431a6b 28 /* ---- Main function (default thread) ----
WilliamMarshQMUL 3:05b6a1431a6b 29 Note that if this thread completes, nothing else works
WilliamMarshQMUL 3:05b6a1431a6b 30 */
WilliamMarshQMUL 3:05b6a1431a6b 31 int main() {
natgovor 4:c8b84240732a 32 // LEDa are on by default
natgovor 4:c8b84240732a 33 redLed = 0;
natgovor 4:c8b84240732a 34 blueLed = 0;
natgovor 4:c8b84240732a 35
natgovor 4:c8b84240732a 36 int flashPeriod = 5;
natgovor 4:c8b84240732a 37 int redBtnCounter = flashPeriod;
natgovor 4:c8b84240732a 38 int blueBtnCounter = flashPeriod;
natgovor 4:c8b84240732a 39
natgovor 4:c8b84240732a 40 bool redIsFlashing = true;
natgovor 4:c8b84240732a 41 bool blueIsFlashing = true;
natgovor 4:c8b84240732a 42
natgovor 4:c8b84240732a 43 redButton.mode(PullUp); // Ensure button i/p has pull up
natgovor 4:c8b84240732a 44 redButton.fall(&redButtonCallback) ; // Attach function to falling edge
natgovor 4:c8b84240732a 45 blueButton.mode(PullUp); // Ensure button i/p has pull up
natgovor 4:c8b84240732a 46 blueButton.fall(&blueButtonCallback) ; // Attach function to falling edge
WilliamMarshQMUL 3:05b6a1431a6b 47
WilliamMarshQMUL 0:a66a8cb0012c 48 while(true) {
natgovor 4:c8b84240732a 49 Thread::wait(100);
natgovor 4:c8b84240732a 50 if (redIsFlashing) {
natgovor 4:c8b84240732a 51 redBtnCounter--;
natgovor 4:c8b84240732a 52 }
natgovor 4:c8b84240732a 53 if (blueIsFlashing) {
natgovor 4:c8b84240732a 54 blueBtnCounter--;
natgovor 4:c8b84240732a 55 }
natgovor 4:c8b84240732a 56
natgovor 4:c8b84240732a 57 if (redBtnCounter == 0) {
natgovor 4:c8b84240732a 58 redLed = !redLed;
natgovor 4:c8b84240732a 59 redBtnCounter = flashPeriod;
WilliamMarshQMUL 0:a66a8cb0012c 60 }
natgovor 4:c8b84240732a 61 if (blueBtnCounter == 0) {
natgovor 4:c8b84240732a 62 blueLed = !blueLed;
natgovor 4:c8b84240732a 63 blueBtnCounter = flashPeriod;
natgovor 4:c8b84240732a 64 }
natgovor 4:c8b84240732a 65
natgovor 4:c8b84240732a 66 // Stop flashing (freeze in the current state) every time the button is pressed
natgovor 4:c8b84240732a 67 if (redPressEvent) {
natgovor 4:c8b84240732a 68 redIsFlashing = !redIsFlashing;
natgovor 4:c8b84240732a 69 redPressEvent = 0; // Clear the event variable
natgovor 4:c8b84240732a 70 }
natgovor 4:c8b84240732a 71 if (bluePressEvent) {
natgovor 4:c8b84240732a 72 blueIsFlashing = !blueIsFlashing;
natgovor 4:c8b84240732a 73 bluePressEvent = 0; // Clear the event variable
natgovor 4:c8b84240732a 74 }
WilliamMarshQMUL 0:a66a8cb0012c 75 }
WilliamMarshQMUL 0:a66a8cb0012c 76 }