debounce_button.cpp

00001 #include "debounce_button.h"
00002 
00003 /**
00004     TODO
00005     ----
00006     -   A debouncer has to be present: the built-in buttons of the Nucleo aren't that good, so false positives have to be filtered out. 
00007         Find a method such that false calls of this function are going to be filtered out. 
00008         The main loop also needs to know when it can process the further instructions.
00009         An acceptable time to disable further false positives is between 50ms and 100ms.
00010     -   The user needs to be able to click the button multiple times in 1 second. 
00011         The main loop needs to know how many times the user has pressed the button, such that
00012         it can link different procedures to the different multiclicks. The main loop also needs
00013         to know when this function is counting the clicks. Therefore, it has to wait until the clicks have been counted
00014         before it can proceed.
00015     -   LED1 needs to be turned on while the function is counting the amount of clicks within 1 second.
00016     
00017     Some tips and tricks:
00018     -   To use the built-in LED:
00019             DigitalOut led1(LED1);
00020             ...
00021             led1 = 1;
00022     -   To delay the call of a function:
00023             Timeout someTimeout;
00024             ...
00025             someTimeout.attach(callback(&anotherFunction), 0.5) with 0.5 as 500 milliseconds
00026     -   The variables that are used in interrupt callbacks have to be volatile, 
00027         because these variables can change at any time. Therefore, the compiler is not 
00028         going to make optimisations.
00029     -   Use boolean flags to send information between different processes.
00030     -   In the header file are extra functions and variables that can help you developing these procedures.
00031         You can add, change or remove these functions and variables at any time, as long as it is clear what you've done.
00032 */
00033 
00034 /**
00035     This function is called when the button has been pressed by the user.
00036 */
00037 
00038 Timeout timeout1;
00039 Timeout timeout2;
00040 DigitalOut busy_led(LED1);
00041 volatile bool button1_pressed=false;   // Used in the main loop
00042 volatile bool button1_enabled=true;   // Used for debouncing
00043 volatile int multiclick_state=0;   // Counts how many clicks occured in the time slot, used in main loop
00044 volatile int last_multiclick_state=0;   // Counts how many clicks occured in the previous timeslot
00045 volatile bool button1_busy = false;      // Informs the mainloop that the user is clicking the button
00046 volatile bool result_ready=false;
00047 
00048 void button1_onpressed_cb(void)
00049 {
00050     if(button1_enabled)
00051     {
00052         if(multiclick_state == 0) //first press this second
00053         {
00054             button1_busy=true;
00055             busy_led = 1;
00056             timeout1.attach(callback(&button1_multiclick_reset_cb), 1.0);           
00057         }
00058         multiclick_state += 1;
00059         button1_enabled=false;        
00060         timeout2.attach(callback(&button1_enabled_cb), 0.075);
00061     }
00062 }
00063 
00064 /**
00065     Resets the amount of clicks, but stores this value for the usage in the main loop
00066 */
00067 void button1_multiclick_reset_cb()
00068 {
00069     last_multiclick_state = multiclick_state;
00070     multiclick_state = 0;
00071     button1_busy=false;
00072     result_ready=true;
00073     busy_led=0;
00074 }
00075 
00076 /**
00077     Enables the button again after a timeout, used for debouncing the button 
00078 */
00079 void button1_enabled_cb()
00080 {
00081     button1_enabled=true;
00082 }