University of Plymouth - Stages 1, 2 and 3 / Mbed OS Task327

Lab version

Fork of Task327 by Nicholas Outram

main.cpp@4:c85556b07606, 2017-10-12 (annotated)

Committer:
noutram
Date:
Thu Oct 12 14:57:29 2017 +0000
Revision:
4:c85556b07606
Parent:
3:384a8f9726ac
Child:
5:26484016d498
Now even simpler

Who changed what in which revision?

UserRevisionLine numberNew contents of line
noutram 0:bf0e4c6e1f4d 1 #include "mbed.h"
noutram 0:bf0e4c6e1f4d 2
noutram 3:384a8f9726ac 3 void updateState();
noutram 0:bf0e4c6e1f4d 4 void sw1RisingEdge();
noutram 0:bf0e4c6e1f4d 5 void sw1FallingEdge();
noutram 0:bf0e4c6e1f4d 6
noutram 0:bf0e4c6e1f4d 7 #define EDGE_RISEN 1
noutram 0:bf0e4c6e1f4d 8 #define EDGE_FALLEN 0
noutram 0:bf0e4c6e1f4d 9
noutram 0:bf0e4c6e1f4d 10 //Global Objects
noutram 3:384a8f9726ac 11 DigitalOut led(LED1);
noutram 2:23bd19542152 12 InterruptIn sw1(USER_BUTTON);
noutram 3:384a8f9726ac 13
noutram 3:384a8f9726ac 14 //State
noutram 3:384a8f9726ac 15 static int sw1State = EDGE_FALLEN; //Initial state for switch 1
noutram 0:bf0e4c6e1f4d 16
noutram 0:bf0e4c6e1f4d 17 //Interrupt service routine for handling the timeout
noutram 3:384a8f9726ac 18 void updateState() {
noutram 3:384a8f9726ac 19
noutram 3:384a8f9726ac 20 //Allow for switch bounce
noutram 3:384a8f9726ac 21 wait(0.1);
noutram 3:384a8f9726ac 22
noutram 0:bf0e4c6e1f4d 23 //Which event does this follow?
noutram 0:bf0e4c6e1f4d 24 switch (sw1State) {
noutram 0:bf0e4c6e1f4d 25 case EDGE_RISEN:
noutram 4:c85556b07606 26 sw1.fall(callback(&sw1FallingEdge)); //Now wait for a falling edge
noutram 0:bf0e4c6e1f4d 27 break;
noutram 0:bf0e4c6e1f4d 28 case EDGE_FALLEN:
noutram 4:c85556b07606 29 sw1.rise(callback(&sw1RisingEdge)); //Now wait for a rising edge
noutram 0:bf0e4c6e1f4d 30 break;
noutram 0:bf0e4c6e1f4d 31 } //end switch
noutram 0:bf0e4c6e1f4d 32 }
noutram 0:bf0e4c6e1f4d 33
noutram 0:bf0e4c6e1f4d 34 //Interrupt service routine for a rising edge (press)
noutram 0:bf0e4c6e1f4d 35 void sw1RisingEdge() {
noutram 0:bf0e4c6e1f4d 36 sw1.rise(NULL); //Disable detecting more rising edges
noutram 0:bf0e4c6e1f4d 37 sw1State = EDGE_RISEN; //Flag state
noutram 0:bf0e4c6e1f4d 38 }
noutram 0:bf0e4c6e1f4d 39
noutram 0:bf0e4c6e1f4d 40 //Interrupt service routive for SW1 falling edge (release)
noutram 0:bf0e4c6e1f4d 41 void sw1FallingEdge() {
noutram 3:384a8f9726ac 42 sw1.fall(NULL); //Disable this interrupt
noutram 0:bf0e4c6e1f4d 43 sw1State = EDGE_FALLEN; //Flag state
noutram 0:bf0e4c6e1f4d 44 }
noutram 0:bf0e4c6e1f4d 45
noutram 0:bf0e4c6e1f4d 46 //Main - only has to initialise and sleep
noutram 0:bf0e4c6e1f4d 47 int main() {
noutram 0:bf0e4c6e1f4d 48
noutram 0:bf0e4c6e1f4d 49 //Configure interrupts, wait for first rising edge
noutram 4:c85556b07606 50 sw1.rise(callback(&sw1RisingEdge));
noutram 0:bf0e4c6e1f4d 51
noutram 4:c85556b07606 52 //Set LED to ON
noutram 4:c85556b07606 53 led = 1;
noutram 4:c85556b07606 54
noutram 0:bf0e4c6e1f4d 55 //Main Polling Loop
noutram 0:bf0e4c6e1f4d 56 while (true) {
noutram 4:c85556b07606 57
noutram 0:bf0e4c6e1f4d 58 //Put CPU back to sleep
noutram 3:384a8f9726ac 59 sleep(); //woken by rising edge
noutram 3:384a8f9726ac 60 puts("Rising");
noutram 3:384a8f9726ac 61 updateState();
noutram 3:384a8f9726ac 62
noutram 2:23bd19542152 63 sleep(); //Falling edge
noutram 2:23bd19542152 64 puts("Falling");
noutram 3:384a8f9726ac 65 updateState();
noutram 0:bf0e4c6e1f4d 66
noutram 3:384a8f9726ac 67 //You can ONLY reach this point if an ISR wakes the CPU twice
noutram 4:c85556b07606 68 led = !led;
noutram 0:bf0e4c6e1f4d 69
noutram 0:bf0e4c6e1f4d 70 } //end while
noutram 0:bf0e4c6e1f4d 71
noutram 0:bf0e4c6e1f4d 72 }