Nicholas Outram / Mbed OS Task324Solution_OO

updated for mbed-os 5.5

main.cpp@0:7da792c21683, 2017-07-13 (annotated)

Committer:
noutram
Date:
Thu Jul 13 14:48:19 2017 +0000
Revision:
0:7da792c21683
updated for mbed-os 5.5

Who changed what in which revision?

UserRevisionLine numberNew contents of line
noutram 0:7da792c21683 1 #include "mbed.h"
noutram 0:7da792c21683 2
noutram 0:7da792c21683 3 DigitalOut red_led(D7);
noutram 0:7da792c21683 4 DigitalOut yellow_led(D6);
noutram 0:7da792c21683 5 DigitalOut green_led(D5);
noutram 0:7da792c21683 6 DigitalIn SW1(D4);
noutram 0:7da792c21683 7 DigitalIn SW2(D3);
noutram 0:7da792c21683 8
noutram 0:7da792c21683 9 //This is the solution based on the proposed flowchart.
noutram 0:7da792c21683 10
noutram 0:7da792c21683 11 class SwitchState {
noutram 0:7da792c21683 12 private:
noutram 0:7da792c21683 13 //Enumerated type (integer)
noutram 0:7da792c21683 14 enum STATE { WAITING4PRESS=1, WAITING4BOUNCE_RISING=2, WAITING4RELEASE=4, WAITING4BOUNCE_FALLING=8 };
noutram 0:7da792c21683 15
noutram 0:7da792c21683 16 STATE state; //Current state in the FSM
noutram 0:7da792c21683 17 DigitalIn& sw; //Reference to a GPIO Input
noutram 0:7da792c21683 18 DigitalOut& led; //Reference to a GPIO Output
noutram 0:7da792c21683 19 Timer tmr; //Internal timer used for debounce
noutram 0:7da792c21683 20
noutram 0:7da792c21683 21 //Toggle the LED state
noutram 0:7da792c21683 22 void toggleLed() {
noutram 0:7da792c21683 23 led = !led;
noutram 0:7da792c21683 24 }
noutram 0:7da792c21683 25
noutram 0:7da792c21683 26 //Next state (circular pattern)
noutram 0:7da792c21683 27 void gotoNextState() {
noutram 0:7da792c21683 28 state = (state >> 3) | ((state << 1) & 0b1111);
noutram 0:7da792c21683 29 }
noutram 0:7da792c21683 30
noutram 0:7da792c21683 31 //Constructor
noutram 0:7da792c21683 32 public:
noutram 0:7da792c21683 33 SwitchState(DigitalIn& gpioIn, DigitalOut& gpioOut) : sw(gpioIn), led(gpioOut) {
noutram 0:7da792c21683 34 state = WAITING4PRESS;
noutram 0:7da792c21683 35 tmr.stop();
noutram 0:7da792c21683 36 tmr.reset();
noutram 0:7da792c21683 37 }
noutram 0:7da792c21683 38
noutram 0:7da792c21683 39 //Update the state using polling
noutram 0:7da792c21683 40 void updateState()
noutram 0:7da792c21683 41 {
noutram 0:7da792c21683 42 switch (state) {
noutram 0:7da792c21683 43
noutram 0:7da792c21683 44 //Waiting for switch to be pressed
noutram 0:7da792c21683 45 case WAITING4PRESS:
noutram 0:7da792c21683 46
noutram 0:7da792c21683 47 if (sw == 1) {
noutram 0:7da792c21683 48 //Output: start timer
noutram 0:7da792c21683 49 tmr.reset();
noutram 0:7da792c21683 50 tmr.start();
noutram 0:7da792c21683 51
noutram 0:7da792c21683 52 //Next state
noutram 0:7da792c21683 53 gotoNextState();
noutram 0:7da792c21683 54 puts("Entering state: WAITING4BOUNCE_RISING");
noutram 0:7da792c21683 55 }
noutram 0:7da792c21683 56 break;
noutram 0:7da792c21683 57
noutram 0:7da792c21683 58 //Waiting for 50ms to elapse
noutram 0:7da792c21683 59 case WAITING4BOUNCE_RISING:
noutram 0:7da792c21683 60 if (tmr.read_ms() > 50) {
noutram 0:7da792c21683 61 //Outputs: Stop timer
noutram 0:7da792c21683 62 tmr.stop();
noutram 0:7da792c21683 63 //Next state
noutram 0:7da792c21683 64 gotoNextState();
noutram 0:7da792c21683 65 puts("Entering state: WAITING4RELEASE");
noutram 0:7da792c21683 66 }
noutram 0:7da792c21683 67 break;
noutram 0:7da792c21683 68
noutram 0:7da792c21683 69 //Waiting for switch to be released
noutram 0:7da792c21683 70 case WAITING4RELEASE:
noutram 0:7da792c21683 71 if (sw == 0) {
noutram 0:7da792c21683 72 //Outputs: Toggle the LED and start timer
noutram 0:7da792c21683 73 toggleLed();
noutram 0:7da792c21683 74 tmr.reset();
noutram 0:7da792c21683 75 tmr.start();
noutram 0:7da792c21683 76 //Next state
noutram 0:7da792c21683 77 gotoNextState();
noutram 0:7da792c21683 78 puts("Entering state: WAITING4BOUNCE_FALLING");
noutram 0:7da792c21683 79 }
noutram 0:7da792c21683 80 break;
noutram 0:7da792c21683 81
noutram 0:7da792c21683 82 //Waiting 50ms for switch bounce
noutram 0:7da792c21683 83 case WAITING4BOUNCE_FALLING:
noutram 0:7da792c21683 84 if (tmr.read_ms() > 50) {
noutram 0:7da792c21683 85 //Outputs: Reset timer 1
noutram 0:7da792c21683 86 tmr.stop();
noutram 0:7da792c21683 87 tmr.reset();
noutram 0:7da792c21683 88
noutram 0:7da792c21683 89 //Next state:
noutram 0:7da792c21683 90 gotoNextState();
noutram 0:7da792c21683 91 puts("Entering state: WAITING4PRESS");
noutram 0:7da792c21683 92 }
noutram 0:7da792c21683 93 break;
noutram 0:7da792c21683 94
noutram 0:7da792c21683 95 default:
noutram 0:7da792c21683 96 //Something has gone very wrong
noutram 0:7da792c21683 97 tmr.stop();
noutram 0:7da792c21683 98 tmr.reset();
noutram 0:7da792c21683 99 led = 0;
noutram 0:7da792c21683 100 state = WAITING4PRESS;
noutram 0:7da792c21683 101 puts("ERROR");
noutram 0:7da792c21683 102 break;
noutram 0:7da792c21683 103
noutram 0:7da792c21683 104 } //end switch
noutram 0:7da792c21683 105
noutram 0:7da792c21683 106 }
noutram 0:7da792c21683 107 };
noutram 0:7da792c21683 108
noutram 0:7da792c21683 109
noutram 0:7da792c21683 110 int main() {
noutram 0:7da792c21683 111
noutram 0:7da792c21683 112 //Initial logging message
noutram 0:7da792c21683 113 puts("START");
noutram 0:7da792c21683 114
noutram 0:7da792c21683 115 //Create two objects using different inputs and outputs
noutram 0:7da792c21683 116 SwitchState s1(SW1, red_led);
noutram 0:7da792c21683 117 SwitchState s2(SW2, green_led);
noutram 0:7da792c21683 118
noutram 0:7da792c21683 119 //Main Polling Loop
noutram 0:7da792c21683 120 while (true) {
noutram 0:7da792c21683 121
noutram 0:7da792c21683 122 s1.updateState();
noutram 0:7da792c21683 123 s2.updateState();
noutram 0:7da792c21683 124
noutram 0:7da792c21683 125 } //end while
noutram 0:7da792c21683 126
noutram 0:7da792c21683 127 }
noutram 0:7da792c21683 128
noutram 0:7da792c21683 129