Button Functions

Functions
enum sd_button_err	sd_button_init (struct sd_button *butt, GPIO_TypeDef *port, uint16_t pin, uint32_t up_to, void(*up_cb)(void), uint32_t down_to, void(*down_cb)(void))
	Initialize Button Port/Pin and State Machine. More...
enum sd_button_err	sd_button_run (struct sd_button *butt)
	Run Button State Machine. More...

Detailed Description

Function Documentation

sd_button_init()

enum sd_button_err sd_button_init	(	struct sd_button *	butt,
		GPIO_TypeDef *	port,
		uint16_t	pin,
		uint32_t	up_to,
		void(*)(void)	up_cb,
		uint32_t	down_to,
		void(*)(void)	down_cb
	)

#include <Src/sd_button.c>

Initialize Button Port/Pin and State Machine.

Parameters

butt	Button to initialize
port	GPIO port of button
pin	GPIO pin of button
up_to	Button up debounce timeout
up_cb	Button up callback function
down_to	Button down debounce timeout
down_cb	Button down callback function

Return values

SD_BUTTON_SUCCESS

on success, error code otherwise

{
    butt->port = port;
    butt->pin = pin;
    butt->state = SD_BUTTON_IDLE;
    
    butt->up_to = up_to;
    butt->up_cb = up_cb;
    
    butt->down_to = down_to;
    butt->down_cb = down_cb;
    
    return SD_BUTTON_SUCCESS;
}

sd_button_run()

enum sd_button_err sd_button_run

(

struct sd_button *

butt

)

#include <Src/sd_button.c>

Run Button State Machine.

Parameters

butt	Button to run state machine

Return values

SD_BUTTON_SUCCESS

on success, error code otherwise

{
    switch (butt->state) {
    case SD_BUTTON_IDLE:    
        if (butt->port->IDR & butt->pin) {
            /* The button is not pressed */
        } else {
            /* Record the timer value before transitioning */
            butt->tick = HAL_GetTick();
            butt->state = SD_BUTTON_DOWN_WAIT;  
        }
        break;
    
    case SD_BUTTON_DOWN_WAIT:
        if (butt->port->IDR & butt->pin) {
            /* Debounce was unsuccessful. Return to idle */
            butt->state = SD_BUTTON_IDLE;
        } else {
            /* Check if the timer has expired */
            if (HAL_GetTick() > (butt->tick + butt->down_to)) {
                butt->down_cb();
                butt->state = SD_BUTTON_DOWN_DEB;
            }
        }
            
        break;
    
    case SD_BUTTON_DOWN_DEB:
        if (butt->port->IDR & butt->pin) {
            /* The button has been released */
            butt->tick = HAL_GetTick();
            butt->state = SD_BUTTON_UP_WAIT;
        } else {
            /* The button is still pressed */
        }
        break;
    
    case SD_BUTTON_UP_WAIT:
        if (butt->port->IDR & butt->pin) {
            /* The button detected as released */
            if (HAL_GetTick() > (butt->tick + butt->up_to)) {
                /* Button debounce successful */
                butt->up_cb();
                butt->state = SD_BUTTON_IDLE;
            }
        } else {
            /* The button was detected as pressed */
            butt->state = SD_BUTTON_DOWN_DEB;
        }
        break;
    }
    return SD_BUTTON_SUCCESS;
}