Martin Allen / Mbed OS Task324SolutionWORKING

Toggle 2 Leds with two switches

Fork of Task324Solution by University of Plymouth - Stages 1, 2 and 3

main.cpp@1:b7cc6bbb077d, 2018-03-08 (annotated)

Committer:
martinjamesallen1991
Date:
Thu Mar 08 03:25:49 2018 +0000
Revision:
1:b7cc6bbb077d
Parent:
0:3590cc227050
Child:
2:1874cdaec623
Working Revision

Who changed what in which revision?

UserRevisionLine numberNew contents of line
noutram 0:3590cc227050 1 #include "mbed.h"
noutram 0:3590cc227050 2
noutram 0:3590cc227050 3 DigitalOut red_led(D7);
noutram 0:3590cc227050 4 DigitalOut green_led(D5);
noutram 0:3590cc227050 5 DigitalIn SW1(D4);
noutram 0:3590cc227050 6 DigitalIn SW2(D3);
noutram 0:3590cc227050 7 Timer tmr1;
noutram 0:3590cc227050 8 Timer tmr2;
noutram 0:3590cc227050 9
noutram 0:3590cc227050 10 #define WAITING4PRESS 0
noutram 0:3590cc227050 11 #define WAITING4BOUNCE_RISING 1
noutram 0:3590cc227050 12 #define WAITING4RELEASE 2
noutram 0:3590cc227050 13 #define WAITING4BOUNCE_FALLING 4
noutram 0:3590cc227050 14
noutram 0:3590cc227050 15 // Update the state for a given switch and LED pair
noutram 0:3590cc227050 16 // Parameters:
noutram 0:3590cc227050 17 // sw is the switch input, 0 for released and 1 for pressed, passed by value
noutram 0:3590cc227050 18 // swState is an integer that keeps a record of state, passed by reference (updated by the function)
noutram 0:3590cc227050 19 // led is of type DigitalOut, connected to a LED
noutram 0:3590cc227050 20 // tmr is of type Timer, a reference to unique instance of a timer
noutram 0:3590cc227050 21 // This function cannot be called by an ISR
martinjamesallen1991 1:b7cc6bbb077d 22
noutram 0:3590cc227050 23 void updateState(int sw, int &swState, DigitalOut &led, Timer &tmr)
noutram 0:3590cc227050 24 {
noutram 0:3590cc227050 25 //LED
noutram 0:3590cc227050 26 switch (swState) {
noutram 0:3590cc227050 27
noutram 0:3590cc227050 28 //Waiting for switch to be pressed
noutram 0:3590cc227050 29 case WAITING4PRESS:
noutram 0:3590cc227050 30
noutram 0:3590cc227050 31 if (sw == 1) {
noutram 0:3590cc227050 32 //Output: start timer
noutram 0:3590cc227050 33 tmr.reset();
noutram 0:3590cc227050 34 tmr.start();
noutram 0:3590cc227050 35
noutram 0:3590cc227050 36 //Next state
noutram 0:3590cc227050 37 swState = WAITING4BOUNCE_RISING;
noutram 0:3590cc227050 38 puts("Entering state: WAITING4BOUNCE_RISING");
noutram 0:3590cc227050 39 }
noutram 0:3590cc227050 40 break;
noutram 0:3590cc227050 41
noutram 0:3590cc227050 42 //Waiting for 50ms to elapse
noutram 0:3590cc227050 43 case WAITING4BOUNCE_RISING:
noutram 0:3590cc227050 44 if (tmr.read_ms() > 50) {
noutram 0:3590cc227050 45 //Outputs: Stop timer
noutram 0:3590cc227050 46 tmr.stop();
noutram 0:3590cc227050 47 //Next state
noutram 0:3590cc227050 48 swState = WAITING4RELEASE;
noutram 0:3590cc227050 49 puts("Entering state: WAITING4RELEASE");
noutram 0:3590cc227050 50 }
noutram 0:3590cc227050 51 break;
noutram 0:3590cc227050 52
noutram 0:3590cc227050 53 //Waiting for switch to be released
noutram 0:3590cc227050 54 case WAITING4RELEASE:
noutram 0:3590cc227050 55 if (sw == 0) {
noutram 0:3590cc227050 56 //Outputs: Toggle the LED and start timer
noutram 0:3590cc227050 57 led = !led;
noutram 0:3590cc227050 58 tmr.reset();
noutram 0:3590cc227050 59 tmr.start();
noutram 0:3590cc227050 60 //Next state
noutram 0:3590cc227050 61 swState = WAITING4BOUNCE_FALLING;
noutram 0:3590cc227050 62 puts("Entering state: WAITING4BOUNCE_FALLING");
noutram 0:3590cc227050 63 }
noutram 0:3590cc227050 64 break;
noutram 0:3590cc227050 65
noutram 0:3590cc227050 66 //Waiting 50ms for switch bounce
noutram 0:3590cc227050 67 case WAITING4BOUNCE_FALLING:
noutram 0:3590cc227050 68 if (tmr.read_ms() > 50) {
noutram 0:3590cc227050 69 //Outputs: Reset timer 1
noutram 0:3590cc227050 70 tmr.stop();
noutram 0:3590cc227050 71 tmr.reset();
noutram 0:3590cc227050 72
noutram 0:3590cc227050 73 //Next state:
noutram 0:3590cc227050 74 swState = WAITING4PRESS;
noutram 0:3590cc227050 75 puts("Entering state: WAITING4PRESS");
noutram 0:3590cc227050 76 }
noutram 0:3590cc227050 77 break;
noutram 0:3590cc227050 78
noutram 0:3590cc227050 79 default:
noutram 0:3590cc227050 80 //Something has gone very wrong
noutram 0:3590cc227050 81 tmr.stop();
noutram 0:3590cc227050 82 tmr.reset();
noutram 0:3590cc227050 83 led = 0;
noutram 0:3590cc227050 84 swState = WAITING4PRESS;
noutram 0:3590cc227050 85 puts("ERROR");
noutram 0:3590cc227050 86 break;
noutram 0:3590cc227050 87
noutram 0:3590cc227050 88 } //end switch
martinjamesallen1991 1:b7cc6bbb077d 89 } //end function
martinjamesallen1991 1:b7cc6bbb077d 90
martinjamesallen1991 1:b7cc6bbb077d 91
martinjamesallen1991 1:b7cc6bbb077d 92
martinjamesallen1991 1:b7cc6bbb077d 93 int main() {
martinjamesallen1991 1:b7cc6bbb077d 94 //Initial logging message
martinjamesallen1991 1:b7cc6bbb077d 95 puts("START");
martinjamesallen1991 1:b7cc6bbb077d 96
martinjamesallen1991 1:b7cc6bbb077d 97 //Initial state
martinjamesallen1991 1:b7cc6bbb077d 98 red_led = 0; //Set RED LED to OFF
martinjamesallen1991 1:b7cc6bbb077d 99 green_led = 0;
martinjamesallen1991 1:b7cc6bbb077d 100
martinjamesallen1991 1:b7cc6bbb077d 101 //Switch state
martinjamesallen1991 1:b7cc6bbb077d 102 int sw1State = 0;
martinjamesallen1991 1:b7cc6bbb077d 103 int sw2State = 0;
martinjamesallen1991 1:b7cc6bbb077d 104
martinjamesallen1991 1:b7cc6bbb077d 105 //Timers
martinjamesallen1991 1:b7cc6bbb077d 106 tmr1.stop();
martinjamesallen1991 1:b7cc6bbb077d 107 tmr1.reset();
martinjamesallen1991 1:b7cc6bbb077d 108 tmr2.stop();
martinjamesallen1991 1:b7cc6bbb077d 109 tmr2.reset();
martinjamesallen1991 1:b7cc6bbb077d 110
martinjamesallen1991 1:b7cc6bbb077d 111 //Initial logging message
martinjamesallen1991 1:b7cc6bbb077d 112 puts("Entering state WAITING4PRESS");
martinjamesallen1991 1:b7cc6bbb077d 113
martinjamesallen1991 1:b7cc6bbb077d 114 //Main Polling Loop
martinjamesallen1991 1:b7cc6bbb077d 115 while (true) {
martinjamesallen1991 1:b7cc6bbb077d 116
martinjamesallen1991 1:b7cc6bbb077d 117 //Poll inputs (without blocking)
martinjamesallen1991 1:b7cc6bbb077d 118 int sw1 = SW1;
martinjamesallen1991 1:b7cc6bbb077d 119 int sw2 = SW2;
martinjamesallen1991 1:b7cc6bbb077d 120
martinjamesallen1991 1:b7cc6bbb077d 121 updateState(sw1, sw1State, red_led, tmr1);
martinjamesallen1991 1:b7cc6bbb077d 122 updateState(sw2, sw2State, green_led, tmr2);
martinjamesallen1991 1:b7cc6bbb077d 123
martinjamesallen1991 1:b7cc6bbb077d 124 } //end while
martinjamesallen1991 1:b7cc6bbb077d 125
martinjamesallen1991 1:b7cc6bbb077d 126 }