Alix Germany / Mbed OS Coursework_Version_5

Version 5

Dependencies:   BMP280 TextLCD BME280

SWPoll.hpp@9:f5eae5211225, 2018-12-07 (annotated)

Committer:
Alix955
Date:
Fri Dec 07 13:24:50 2018 +0000
Revision:
9:f5eae5211225
Parent:
0:f9a18207d99c 
Version 5, mine & sams versions merged

Who changed what in which revision?

UserRevisionLine numberNew contents of line
O_Thom 0:f9a18207d99c 1 #include "mbed.h"
O_Thom 0:f9a18207d99c 2 class SWPoll {
O_Thom 0:f9a18207d99c 3 private:
O_Thom 0:f9a18207d99c 4 enum State {LOW, LOW_DEBOUNCE, HIGH, HIGH_DEBOUNCE};
O_Thom 0:f9a18207d99c 5 State state; // Internal state
O_Thom 0:f9a18207d99c 6 DigitalIn& sw; // These are references (aliases) and MUST be initialised
O_Thom 0:f9a18207d99c 7 int status; // ""
O_Thom 0:f9a18207d99c 8 Timer t; // Each instance has it's own timer, so this is is finite
O_Thom 0:f9a18207d99c 9
O_Thom 0:f9a18207d99c 10 public:
O_Thom 0:f9a18207d99c 11 //Constructor - MUST be given two parameters (for the switch and led) BY REFERENCE
O_Thom 0:f9a18207d99c 12 SWPoll(DigitalIn& gpioIn, int flag) : sw(gpioIn), status(flag) {
O_Thom 0:f9a18207d99c 13 state = LOW;
O_Thom 0:f9a18207d99c 14 t.reset();
O_Thom 0:f9a18207d99c 15 flag = 0;
O_Thom 0:f9a18207d99c 16 }
O_Thom 0:f9a18207d99c 17 //Destructor - should the instance go out of scope, this is called
O_Thom 0:f9a18207d99c 18 ~SWPoll() {
O_Thom 0:f9a18207d99c 19 //Shut down
O_Thom 0:f9a18207d99c 20 t.stop();
O_Thom 0:f9a18207d99c 21 t.reset();
O_Thom 0:f9a18207d99c 22 flag = 0;
O_Thom 0:f9a18207d99c 23 }
O_Thom 0:f9a18207d99c 24 //The public API - poll the switches
O_Thom 0:f9a18207d99c 25 //Bascially, a mealy machine - uses a timer to manage switch bounce
O_Thom 0:f9a18207d99c 26 void poll() {
O_Thom 0:f9a18207d99c 27 switch (state)
O_Thom 0:f9a18207d99c 28 {
O_Thom 0:f9a18207d99c 29 //Waiting for switch to rise:
O_Thom 0:f9a18207d99c 30 case LOW:
O_Thom 0:f9a18207d99c 31 if (sw == 1) {
O_Thom 0:f9a18207d99c 32 state = LOW_DEBOUNCE;
O_Thom 0:f9a18207d99c 33 t.reset();
O_Thom 0:f9a18207d99c 34 t.start();
O_Thom 0:f9a18207d99c 35 }
O_Thom 0:f9a18207d99c 36 break;
O_Thom 0:f9a18207d99c 37
O_Thom 0:f9a18207d99c 38 case LOW_DEBOUNCE:
O_Thom 0:f9a18207d99c 39 if (t.read_ms() >= 200) {
O_Thom 0:f9a18207d99c 40 state = HIGH;
O_Thom 0:f9a18207d99c 41 t.stop();
O_Thom 0:f9a18207d99c 42 t.reset();
O_Thom 0:f9a18207d99c 43 }
O_Thom 0:f9a18207d99c 44 break;
O_Thom 0:f9a18207d99c 45
O_Thom 0:f9a18207d99c 46 case HIGH:
O_Thom 0:f9a18207d99c 47 if (sw == 0) {
O_Thom 0:f9a18207d99c 48 flag = !flag; //Toggle output on state transition
O_Thom 0:f9a18207d99c 49 state = HIGH_DEBOUNCE;
O_Thom 0:f9a18207d99c 50 t.reset(); //(purely defensive)
O_Thom 0:f9a18207d99c 51 t.start();
O_Thom 0:f9a18207d99c 52 }
O_Thom 0:f9a18207d99c 53 break;
O_Thom 0:f9a18207d99c 54 case HIGH_DEBOUNCE:
O_Thom 0:f9a18207d99c 55 if (t.read_ms() >= 200) {
O_Thom 0:f9a18207d99c 56 state = LOW;
O_Thom 0:f9a18207d99c 57 t.stop();
O_Thom 0:f9a18207d99c 58 t.reset();
O_Thom 0:f9a18207d99c 59 }
O_Thom 0:f9a18207d99c 60 break;
O_Thom 0:f9a18207d99c 61 default:
O_Thom 0:f9a18207d99c 62 t.stop();
O_Thom 0:f9a18207d99c 63 t.reset();
O_Thom 0:f9a18207d99c 64 state = LOW;
O_Thom 0:f9a18207d99c 65 break;
O_Thom 0:f9a18207d99c 66 } //end switch
O_Thom 0:f9a18207d99c 67
O_Thom 0:f9a18207d99c 68 //This is a Mealy Machine - so no output logic follows
O_Thom 0:f9a18207d99c 69 }
O_Thom 0:f9a18207d99c 70 };