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button.c
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Sun, May 5, 17:51

button.c
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/*
* Copyright (C) 2017 EPFL-LSRO (Laboratoire de Systemes Robotiques).
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "button.h"
#include "../communication.h"
#define BOARD_BUTTON_PORT GPIOE
#define BOARD_BUTTON_PIN GPIO_Pin_2
#define USER_BUTTON_IRQ_CHANNEL EXTI2_IRQn
#define USER_BUTTON_IRQ_LINE EXTI_Line2
#define USER_BUTTON_IRQ_PINSOURCE EXTI_PinSource2
#define USER_BUTTON_IRQ_SOURCE EXTI_PortSourceGPIOE
void (*userButtonStateChangedCallback)(bool); ///< Function called when the button state changes. The bool parameter is true if the button was released.
/**
* @brief Initializes the button module.
* @param stateChangedCallback function pointer to the callback function that
* should be called when the button state changes. If this feature is not used,
* NULL can be passed instead.
*/
void but_Init(void (*stateChangedCallback)(bool))
{
GPIO_InitTypeDef GPIO_InitStruct;
EXTI_InitTypeDef EXTI_InitStruct;
NVIC_InitTypeDef NVIC_InitStruct;
// Initialize the pin as input.
GPIO_InitStruct.GPIO_Pin = BOARD_BUTTON_PIN;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(BOARD_BUTTON_PORT, &GPIO_InitStruct);
// Optionally setup the callback that triggers when the button is pressed or
// released.
userButtonStateChangedCallback = stateChangedCallback;
if(stateChangedCallback != NULL)
{
SYSCFG_EXTILineConfig(USER_BUTTON_IRQ_SOURCE,
USER_BUTTON_IRQ_PINSOURCE);
EXTI_InitStruct.EXTI_Line = USER_BUTTON_IRQ_LINE;
EXTI_InitStruct.EXTI_LineCmd = ENABLE;
EXTI_InitStruct.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStruct.EXTI_Trigger = EXTI_Trigger_Rising_Falling;
EXTI_Init(&EXTI_InitStruct);
NVIC_InitStruct.NVIC_IRQChannel = USER_BUTTON_IRQ_CHANNEL;
NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = USER_BUTTON_IRQ_PRIORITY;
NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0x0;
NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStruct);
}
}
/**
* @brief Gets the current state of the user button.
* @return the state of the button (1=released, 0=pressed).
*/
bool but_GetState(void)
{
return GPIO_ReadInputDataBit(BOARD_BUTTON_PORT, BOARD_BUTTON_PIN) != 0;
}
/**
* @brief Calls the user button callback function.
* @remark: this function is called automatically by the pin change interrupt of
* the user button.
*/
void EXTI2_IRQHandler(void)
{
if(EXTI_GetITStatus(USER_BUTTON_IRQ_LINE) != RESET)
{
if(userButtonStateChangedCallback != NULL)
userButtonStateChangedCallback(but_GetState());
// Clear interrupt flag.
EXTI_ClearITPendingBit(USER_BUTTON_IRQ_LINE);
}
}

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