Duncan Parker
/
digitalInPolling_sample
main.cpp
- Committer:
- duncangparker
- Date:
- 2019-01-24
- Revision:
- 4:fd867d8afe4f
- Parent:
- 3:8d87cbabe37e
File content as of revision 4:fd867d8afe4f:
#include "mbed.h" // Labs 2: Example program for polling an input // -------------------------------------------- // The program uses a thread to poll a digital input // - The thread monitors the position of the button // - When the button transitions up and down, a press event is signaled // - Button bounce is guarded against // A second thread (the default one) checks for the press event and toggles the LED DigitalIn b1(PTD0, PullUp); DigitalOut led(LED1); Thread pollT ; // thread to poll volatile int pressEvent = 0 ; // Variabe set by the polling thread enum buttonPos { up, down, bounce }; // Button positions void polling() { buttonPos pos = up ; int bcounter = 0 ; while (true) { switch (pos) { case up : if (!b1.read()) { // now down pressEvent = 1 ; // transition occurred pos = down ; } break ; case down : if (b1 == 1) { // no longer down bcounter = 3 ; // wait four cycles pos = bounce ; } break ; case bounce : if (b1 == 0) { // down again - button has bounced pos = down ; // no event } else if (bcounter == 0) { pos = up ; // delay passed - reset to up } else { bcounter-- ; // continue waiting } break ; } wait(0.03); } } /* ---- Main function (default thread) ---- Note that if this thread completes, nothing else works */ int main() { led = 1 ; // Initially off pollT.start(callback(polling)); int counter = 2; int rate = 1; //functions with counter while(1){ if(pressEvent){ pressEvent = 0; rate = rate + 2; if(rate > 10){ rate = 1; } } counter--; if(counter == 0){ led = !led; counter = rate; } wait(0.1); } // Functions float LED_SW = 0.2; while(1){ if (pressEvent) { pressEvent = 0; LED_SW = LED_SW + 0.2; if (LED_SW > 1){ LED_SW = 0.2; } } led = !led; wait(LED_SW); } }