Biorobotics 7 / Mbed 2 deprecated State_Machine

State machine

Dependencies:   mbed Adafruit_GFX BioroboticsMotorControl MODSERIAL BioroboticsEMGFilter

Button.h@51:e0e4d7e3de93, 2018-11-05 (annotated)

Committer:
MAHCSnijders
Date:
Mon Nov 05 16:03:39 2018 +0000
Revision:
51:e0e4d7e3de93
Parent:
9:27d00b64076e 
Fixed comments

Who changed what in which revision?

UserRevisionLine numberNew contents of line
brass_phoenix 1:cfa5abca6d43 1 #pragma once
brass_phoenix 1:cfa5abca6d43 2
brass_phoenix 1:cfa5abca6d43 3 #include "mbed.h"
brass_phoenix 1:cfa5abca6d43 4
brass_phoenix 3:4b19b6cf6cc7 5 class Button
brass_phoenix 3:4b19b6cf6cc7 6 {
brass_phoenix 1:cfa5abca6d43 7 private:
brass_phoenix 7:e7f808875bc4 8 DigitalIn pin;
brass_phoenix 3:4b19b6cf6cc7 9
brass_phoenix 7:e7f808875bc4 10 volatile bool last_state;
brass_phoenix 1:cfa5abca6d43 11 volatile bool pressed;
brass_phoenix 3:4b19b6cf6cc7 12
brass_phoenix 1:cfa5abca6d43 13 volatile bool just_switched_to_pressed;
brass_phoenix 1:cfa5abca6d43 14 volatile bool just_got_pressed;
brass_phoenix 3:4b19b6cf6cc7 15
brass_phoenix 1:cfa5abca6d43 16 public:
brass_phoenix 1:cfa5abca6d43 17 Button(PinName pin_name):
brass_phoenix 3:4b19b6cf6cc7 18 pin(pin_name) {
brass_phoenix 3:4b19b6cf6cc7 19
brass_phoenix 7:e7f808875bc4 20 last_state = false;
brass_phoenix 1:cfa5abca6d43 21 pressed = false;
brass_phoenix 7:e7f808875bc4 22
brass_phoenix 7:e7f808875bc4 23 just_switched_to_pressed = false;
brass_phoenix 7:e7f808875bc4 24 just_got_pressed = false;
brass_phoenix 7:e7f808875bc4 25 }
brass_phoenix 7:e7f808875bc4 26
brass_phoenix 7:e7f808875bc4 27 void poll_pin() {
brass_phoenix 7:e7f808875bc4 28 // We need to poll the pins periodically.
brass_phoenix 7:e7f808875bc4 29 // Normally one would use rise and fall interrupts, so this wouldn't be
brass_phoenix 7:e7f808875bc4 30 // needed. But the buttons we use generate so much chatter that
brass_phoenix 7:e7f808875bc4 31 // sometimes a rising or a falling edge doesn't get registered.
brass_phoenix 7:e7f808875bc4 32 // With all the confusion that accompanies it.
brass_phoenix 7:e7f808875bc4 33
brass_phoenix 7:e7f808875bc4 34 bool state = !pin;
brass_phoenix 7:e7f808875bc4 35
brass_phoenix 7:e7f808875bc4 36 // Debounce the button by looking over two periods.
brass_phoenix 9:27d00b64076e 37 if (last_state && state && !pressed) {
brass_phoenix 7:e7f808875bc4 38 pressed = true;
brass_phoenix 7:e7f808875bc4 39 just_switched_to_pressed = true;
brass_phoenix 7:e7f808875bc4 40 }
brass_phoenix 7:e7f808875bc4 41
brass_phoenix 7:e7f808875bc4 42 if (!state) {
brass_phoenix 7:e7f808875bc4 43 pressed = false;
brass_phoenix 7:e7f808875bc4 44 }
brass_phoenix 7:e7f808875bc4 45
brass_phoenix 7:e7f808875bc4 46 last_state = state;
brass_phoenix 1:cfa5abca6d43 47 }
brass_phoenix 3:4b19b6cf6cc7 48
brass_phoenix 1:cfa5abca6d43 49 void update() {
brass_phoenix 1:cfa5abca6d43 50 if (just_got_pressed) {
brass_phoenix 1:cfa5abca6d43 51 just_got_pressed = false;
brass_phoenix 1:cfa5abca6d43 52 }
brass_phoenix 1:cfa5abca6d43 53 if (just_switched_to_pressed) {
brass_phoenix 1:cfa5abca6d43 54 just_got_pressed = true;
brass_phoenix 1:cfa5abca6d43 55 just_switched_to_pressed = false;
brass_phoenix 1:cfa5abca6d43 56 }
brass_phoenix 1:cfa5abca6d43 57 }
brass_phoenix 3:4b19b6cf6cc7 58
brass_phoenix 3:4b19b6cf6cc7 59 bool is_pressed() {
brass_phoenix 3:4b19b6cf6cc7 60 return pressed;
brass_phoenix 3:4b19b6cf6cc7 61 };
brass_phoenix 1:cfa5abca6d43 62 // Only active just after a state change from not pressed to pressed.
brass_phoenix 1:cfa5abca6d43 63 // Get's reset after `update()` is called.
brass_phoenix 3:4b19b6cf6cc7 64 bool has_just_been_pressed() {
brass_phoenix 3:4b19b6cf6cc7 65 return just_got_pressed;
brass_phoenix 3:4b19b6cf6cc7 66 };
brass_phoenix 1:cfa5abca6d43 67 };