buttons.c File Reference

#include "buttons.h"
#include "rit.h"
#include <LPC17xx.h>
#include <stdbool.h>

Go to the source code of this file.

Functions
_DECL_EXTERNALLY void	handle_debouncing (void)
	RIT job for handling debouncing. Defined & used in button_irq.c.
BUTTON_Error	BUTTON_Init (u8 options)
	Initializes the BUTTON peripherals.
void	BUTTON_Deinit (void)
	Deinitializes the buttons, by removing all jobs, disabling the interrupts, and removing the debouncing job from the RIT.

Variables
_USED_EXTERNALLY bool	debouncer_on = false
	Flag to indicate if the debouncer is currently active. Used in button_irq.c.

Function Documentation

BUTTON_Deinit()

void BUTTON_Deinit

(

void

)

Deinitializes the buttons, by removing all jobs, disabling the interrupts, and removing the debouncing job from the RIT.

Definition at line 43 of file buttons.c.

{
    // Disabling EINT[0..2] in PINSEL4. In the table, these PINS behave
    // like EINTs when set to 01.
    LPC_PINCON->PINSEL4 &= ~(0b010101 << 20);
    LPC_SC->EXTMODE = 0x0;
    LPC_SC->EXTPOLAR = 0x0;
 
    NVIC_DisableIRQ(EINT0_IRQn);
    NVIC_DisableIRQ(EINT1_IRQn);
    NVIC_DisableIRQ(EINT2_IRQn);
 
    if (debouncer_on)
    {
        debouncer_on = false;
        RIT_RemoveJob(handle_debouncing);
    }
}

BUTTON_Init()

BUTTON_Error BUTTON_Init

(

u8

options

)

Initializes the BUTTON peripherals.

Parameters

options

Button options from the BUTTON_Config enum

Returns

BUTTON_Error The error.

Definition at line 15 of file buttons.c.

{
    // Enabling EINT[0..2] in PINSEL4. In the table, these PINS behave
    // like EINTs when set to 01.
    LPC_PINCON->PINSEL4 |= (0b010101 << 20);
 
    // EITs mapped to PINs 2.[10..12]. Need to set them to 0, i.e. input.
    LPC_GPIO2->FIODIR &= ~(0b111 << 10);
 
    // Setting how EINTs are raised using EXTMODE in SC. Setting 1 to the
    // bottom 3 bits to set interrupt edge sensitive. Since we're not modifying
    // EXTPOLAR in SC, ints are raised on FALLING EDGE.
    LPC_SC->EXTMODE = 0x7;
    LPC_SC->EXTPOLAR = 0x0;
    
    if (options & BTN_DEBOUNCE_WITH_RIT)
    {
        if (!RIT_IsEnabled())
            return BTN_ERR_RIT_UNINIT;
 
        debouncer_on = true;
        RIT_AddJob(handle_debouncing, RIT_NO_DIVIDER);
        RIT_EnableJob(handle_debouncing);
    }
 
    return BTN_ERR_OK;
}

handle_debouncing()

_DECL_EXTERNALLY void handle_debouncing

(

void

)

RIT job for handling debouncing. Defined & used in button_irq.c.

RIT job for handling debouncing. Defined & used in button_irq.c.

Definition at line 29 of file buttons_irq.c.

{
    if (eint0_down)
    {
        eint0_down++;
 
        // If P2.10 is low, button is pressed
        if ((LPC_GPIO2->FIOPIN & (1 << 10)) == 0)
        {
            if (eint0_down == 2 && handlers[BTN_SRC_EINT0].handler)
                handlers[BTN_SRC_EINT0].handler();
        }
        else
        {
            eint0_down = 0;
            NVIC_EnableIRQ(EINT0_IRQn);       // Enabling the interrupt again
            SET_BIT(LPC_PINCON->PINSEL4, 20); // Set P2.10 back to 01 (EINT0)
        }
    }
 
    if (eint1_down)
    {
        eint1_down++;
        if ((LPC_GPIO2->FIOPIN & (1 << 11)) == 0)
        {
            if (eint1_down == 2 && handlers[BTN_SRC_EINT1].handler)
                handlers[BTN_SRC_EINT1].handler();
        }
        else
        {
            eint1_down = 0;
            NVIC_EnableIRQ(EINT1_IRQn);       // Enabling the interrupt again
            SET_BIT(LPC_PINCON->PINSEL4, 22); // Set P2.11 back to 01 (EINT1)
        }
    }
 
    if (eint2_down)
    {
        eint2_down++;
        if ((LPC_GPIO2->FIOPIN & (1 << 12)) == 0)
        {
            if (eint2_down == 2 && handlers[BTN_SRC_EINT2].handler)
                handlers[BTN_SRC_EINT2].handler();
        }
        else
        {
            eint2_down = 0;
            NVIC_EnableIRQ(EINT2_IRQn);       // Enabling the interrupt again
            SET_BIT(LPC_PINCON->PINSEL4, 24); // Set P2.12 back to 01 (EINT2)
        }
    }
}

Variable Documentation

debouncer_on

_USED_EXTERNALLY bool debouncer_on = false

Flag to indicate if the debouncer is currently active. Used in button_irq.c.

Definition at line 8 of file buttons.c.