buttons_irq.c File Reference

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

Go to the source code of this file.

Classes
struct	InterruptHandlerWrapper

Functions
void	handle_debouncing (void)
	RIT job for managing debouncing.
BUTTON_Error	BUTTON_EnableSource (BUTTON_Source source, u8 int_priority)
	Enables the interrupt generation of the given source, provided that there's a function associated to it.
void	BUTTON_DisableSource (BUTTON_Source source)
	Disables the interrupt generation of the given source, but it leaves the function binding.
void	BUTTON_SetFunction (BUTTON_Source source, BUTTON_Function func)
	Binds a given interrupt to a functionality.
void	BUTTON_UnsetFunction (BUTTON_Source source)
	Unbinds the previously set function from the selected interrupt source.
void	EINT0_IRQHandler (void)
void	EINT1_IRQHandler (void)
void	EINT2_IRQHandler (void)

Variables
_PRIVATE InterruptHandlerWrapper	handlers [BTN_SRC_COUNT] = {NULL}
	Array of function pointers to the interrupt handlers for each BUTTON peripheral. This is defined regardless of the debouncing option, since the handlers will be used by the debouncing code as well. Hence the array is marked _USED_EXTERNALLY.
_PRIVATE u8	eint0_down
	Flag to indicate if the button is currently pressed. Used for debouncing.
_PRIVATE u8	eint1_down
_PRIVATE u8	eint2_down
_DECL_EXTERNALLY bool	debouncer_on
	Flag to indicate if the debouncer is currently active.

Function Documentation

BUTTON_DisableSource()

void BUTTON_DisableSource

(

BUTTON_Source

source

)

Disables the interrupt generation of the given source, but it leaves the function binding.

Parameters

source

THe source to disable.

Definition at line 121 of file buttons_irq.c.

{
    if (!handlers[source].handler)
        return; // No handler associated
 
    handlers[source].source_enabled = false;
}

BUTTON_EnableSource()

BUTTON_Error BUTTON_EnableSource	(	BUTTON_Source	source,
		u8	int_priority
	)

Enables the interrupt generation of the given source, provided that there's a function associated to it.

Parameters

source	The source to enable.
int_priority	The priority to assign to the specified source.

Definition at line 84 of file buttons_irq.c.

{
    if (!handlers[source].handler)
        return BTN_ERR_NO_HANDLER_TO_ENABLE; // No handler associated
 
    handlers[source].source_enabled = true;
 
    switch (source)
    {
    case BTN_SRC_EINT0:
        NVIC_EnableIRQ(EINT0_IRQn);
        if (!IS_DEF_PRIORITY(int_priority) && IS_BETWEEN_EQ(int_priority, 0, 15))
            NVIC_SetPriority(EINT0_IRQn, int_priority);
        else
            return BTN_ERR_INT_PRIO_INVALID;
        break;
    case BTN_SRC_EINT1:
        NVIC_EnableIRQ(EINT1_IRQn);
        if (!IS_DEF_PRIORITY(int_priority) && IS_BETWEEN_EQ(int_priority, 0, 15))
            NVIC_SetPriority(EINT1_IRQn, int_priority);
        else
            return BTN_ERR_INT_PRIO_INVALID;
        break;
    case BTN_SRC_EINT2:
        NVIC_EnableIRQ(EINT2_IRQn);
        if (!IS_DEF_PRIORITY(int_priority) && IS_BETWEEN_EQ(int_priority, 0, 15))
            NVIC_SetPriority(EINT2_IRQn, int_priority);
        else
            return BTN_ERR_INT_PRIO_INVALID;
        break;
    default:
        return BTN_ERR_NO_HANDLER_TO_ENABLE;
    }
 
    return BTN_ERR_OK;
}

BUTTON_SetFunction()

void BUTTON_SetFunction	(	BUTTON_Source	source,
		BUTTON_Function	func
	)

Binds a given interrupt to a functionality.

Parameters

source	Button interrupt source (enum BUTTON_Source)
handler	Function pointer to the interrupt handler.
int_priority	The priority to assign to the interrupts coming from the selected source.
enable	Whether to enable the function binding right away.

Definition at line 129 of file buttons_irq.c.

{
    handlers[source] = (InterruptHandlerWrapper){
        .handler = func,
        .source_enabled = false,
    };
}

BUTTON_UnsetFunction()

void BUTTON_UnsetFunction

(

BUTTON_Source

source

)

Unbinds the previously set function from the selected interrupt source.

Parameters

source

Interrupt source (enum BUTTON_Source)

Definition at line 137 of file buttons_irq.c.

{
    handlers[source] = (InterruptHandlerWrapper){
        .handler = NULL,
        .source_enabled = false,
    };
}

EINT0_IRQHandler()

void EINT0_IRQHandler ( void  )

extern

Note

3rd button on the board (next to RESET)

Definition at line 148 of file buttons_irq.c.

{
    if (!handlers[BTN_SRC_EINT0].source_enabled || !handlers[BTN_SRC_EINT0].handler)
        return;
 
    if (debouncer_on)
    {
        eint0_down = 1;
        NVIC_DisableIRQ(EINT0_IRQn);
        CLR_BIT(LPC_PINCON->PINSEL4, 20); // Set P2.10 to 00 (GPIO, previously EINT0)
    }
    else
        handlers[BTN_SRC_EINT0].handler();
 
    LPC_SC->EXTINT &= 1; // Clear the interrupt flag
}

EINT1_IRQHandler()

void EINT1_IRQHandler ( void  )

extern

Note

Left-most button on the board

Definition at line 166 of file buttons_irq.c.

{
    if (!handlers[BTN_SRC_EINT1].source_enabled || !handlers[BTN_SRC_EINT1].handler)
        return;
 
    if (debouncer_on)
    {
        eint1_down = 1;
        NVIC_DisableIRQ(EINT1_IRQn);
        CLR_BIT(LPC_PINCON->PINSEL4, 22); // Set P2.11 to 00 (GPIO, previously EINT1)
    }
    else
        handlers[BTN_SRC_EINT1].handler();
 
    LPC_SC->EXTINT &= 1 << 1; // Clear the interrupt flag
}

EINT2_IRQHandler()

void EINT2_IRQHandler ( void  )

extern

Note

2nd button from the left on the board

Definition at line 184 of file buttons_irq.c.

{
    if (!handlers[BTN_SRC_EINT2].source_enabled || !handlers[BTN_SRC_EINT1].handler)
        return;
 
    if (debouncer_on)
    {
        eint2_down = 1;
        NVIC_DisableIRQ(EINT2_IRQn);
        CLR_BIT(LPC_PINCON->PINSEL4, 24); // Set P2.12 to 00 (GPIO, previously EINT2)
    }
    else
        handlers[BTN_SRC_EINT2].handler();
 
    LPC_SC->EXTINT &= 1 << 2; // Clear the interrupt flag
}

handle_debouncing()

void handle_debouncing

(

void

)

RIT job for managing debouncing.

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

_DECL_EXTERNALLY bool debouncer_on

Flag to indicate if the debouncer is currently active.

Definition at line 26 of file buttons_irq.c.

eint0_down

_PRIVATE u8 eint0_down

Flag to indicate if the button is currently pressed. Used for debouncing.

Definition at line 23 of file buttons_irq.c.

eint1_down

_PRIVATE u8 eint1_down

Definition at line 23 of file buttons_irq.c.

eint2_down

_PRIVATE u8 eint2_down

Definition at line 23 of file buttons_irq.c.

handlers

_PRIVATE InterruptHandlerWrapper handlers[BTN_SRC_COUNT] = {NULL}

Array of function pointers to the interrupt handlers for each BUTTON peripheral. This is defined regardless of the debouncing option, since the handlers will be used by the debouncing code as well. Hence the array is marked _USED_EXTERNALLY.

Note

This array is updated by BUTTON_SetInterruptHandler() and BUTTON_UnsetInterruptHandler().

Definition at line 20 of file buttons_irq.c.

{NULL};