Andrea Vicari / Mbed OS BlinkButton2Sec

Create an Mbed program that - Outputs a string every time the button is pressed - Blinks LED1 if the button is pressed twice within two seconds - Use time_t seconds = time(NULL) to get current time

main.cpp@1:916c0b2b9f1c, 2018-11-29 (annotated)

Committer:
vicara
Date:
Thu Nov 29 17:23:36 2018 +0000
Revision:
1:916c0b2b9f1c
Parent:
0:9758d6dc0132 
2;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
vicara 0:9758d6dc0132 1 #include "mbed.h"
vicara 0:9758d6dc0132 2
vicara 0:9758d6dc0132 3 DigitalOut led1(LED1);
vicara 0:9758d6dc0132 4 InterruptIn button(USER_BUTTON);
vicara 0:9758d6dc0132 5 EventQueue queue(32 * EVENTS_EVENT_SIZE);
vicara 0:9758d6dc0132 6 Thread t;
vicara 0:9758d6dc0132 7 time_t pressed_seconds = time(NULL);
vicara 0:9758d6dc0132 8
vicara 0:9758d6dc0132 9 void blink_led(){
vicara 1:916c0b2b9f1c 10 // Blink the led two times if button pressed two times in two seconds
vicara 0:9758d6dc0132 11 led1 = !led1;
vicara 0:9758d6dc0132 12 wait(0.5);
vicara 0:9758d6dc0132 13 led1 = !led1;
vicara 0:9758d6dc0132 14 wait(0.5);
vicara 0:9758d6dc0132 15 led1 = !led1;
vicara 0:9758d6dc0132 16 wait(0.5);
vicara 0:9758d6dc0132 17 led1 = !led1;
vicara 0:9758d6dc0132 18 }
vicara 0:9758d6dc0132 19 void rise_handler_thread_context(void) {
vicara 0:9758d6dc0132 20 if(pressed_seconds - time(NULL) > 2){
vicara 0:9758d6dc0132 21 pressed_seconds = time(NULL);
vicara 0:9758d6dc0132 22 } else {
vicara 0:9758d6dc0132 23 blink_led();
vicara 0:9758d6dc0132 24 pressed_seconds = time(NULL);
vicara 0:9758d6dc0132 25 }
vicara 0:9758d6dc0132 26 }
vicara 0:9758d6dc0132 27
vicara 0:9758d6dc0132 28 void rise_handler_iterrupt_context(void) {
vicara 0:9758d6dc0132 29 // Execute the time critical part first
vicara 0:9758d6dc0132 30 // The rest can execute later in user context (and can contain code that's not interrupt safe)
vicara 0:9758d6dc0132 31 // We use the 'queue.call' function to add an event (the call to 'rise_handler_user_context') to the queue
vicara 0:9758d6dc0132 32 queue.call(rise_handler_thread_context);
vicara 0:9758d6dc0132 33 }
vicara 0:9758d6dc0132 34
vicara 0:9758d6dc0132 35 void fall_handler(void) {
vicara 0:9758d6dc0132 36 printf("I am a string\n");
vicara 0:9758d6dc0132 37 }
vicara 0:9758d6dc0132 38
vicara 0:9758d6dc0132 39 int main() {
vicara 0:9758d6dc0132 40 // Start the event queue
vicara 0:9758d6dc0132 41 t.start(callback(&queue, &EventQueue::dispatch_forever));
vicara 0:9758d6dc0132 42 printf("Starting in context %p\r\n", Thread::gettid());
vicara 0:9758d6dc0132 43 // The 'rise' handler will execute in IRQ context
vicara 0:9758d6dc0132 44 button.rise(rise_handler_iterrupt_context);
vicara 0:9758d6dc0132 45 // The 'fall' handler will execute in the context of thread 't'
vicara 0:9758d6dc0132 46 button.fall(queue.event(fall_handler));
vicara 0:9758d6dc0132 47 }