nes-proj/platform/avr-ravenlcd/key.c

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/*
* Copyright (c) 2008 Swedish Institute of Computer Science
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of the copyright holders nor the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* \brief
* This file provides joystick operations. Combined with ADC functions.
*
* \author
* Mike Vidales mavida404@gmail.com
*
*/
#include "key.h"
#include "uart.h"
#include "main.h"
#include "adc.h"
/**
* \addtogroup lcd
* \{
*/
/*---------------------------------------------------------------------------*/
/**
* \brief This will intialize the joystick and the ADC for button readings.
*/
void
key_init(void)
{
/* Disable digital input buffer for joystick signal */
DIDR0 |= (1 << ADC1D);
/* Enter is input w/pullup */
ENTER_DDR &= ~(1<<ENTER_PIN);
ENTER_PUR |= (1<<ENTER_PIN);
/* Joystick is input wo/pullup (all though normal port function is overridden by ADC module when reading) */
KEY_DDR &= ~(1<<KEY_PIN);
KEY_PUR &= ~(1<<KEY_PIN);
/* Get the ADC ready to use */
adc_init(ADC_CHAN_ADC1, ADC_TRIG_FREE_RUN, ADC_REF_AVCC, ADC_PS_128);
}
/*---------------------------------------------------------------------------*/
/**
* \brief This will disable the ADC used for button readings.
*/
void
key_deinit(void)
{
/* Turn off the ADC */
adc_deinit();
}
/*---------------------------------------------------------------------------*/
/**
* \brief This will poll run key_task() to determine if a button has been pressed.
*
* \retval True if button is pressed
* \retval False if button is not pressed
*/
uint8_t
is_button(void)
{
/* Return true if button has been pressed. */
if (key_task() == KEY_NO_KEY){
return false;
}
else{
return true;
}
}
/*---------------------------------------------------------------------------*/
/**
* \brief This function will wait for a user to press a button.
*
* \return retval Returns the global button state.
*/
uint8_t
get_button(void)
{
uint8_t retval;
while (!is_button())
;
retval = button;
button = KEY_STATE_DONE;
return retval;
}
/*---------------------------------------------------------------------------*/
/**
* \brief This will check the joystick state to return the current button status.
*
* \return button Current button state.
*/
key_state_t
key_task(void)
{
key_state_t key_state;
/* Check joystick state. Post event if any change since last */
key_state = key_state_get();
if (key_state == KEY_STATE_NO_KEY){
if (button == KEY_STATE_DONE){
button = KEY_STATE_NO_KEY;
}
return KEY_NO_KEY;
}
/* Key_state is button press code */
if (button == KEY_STATE_DONE){
/*
* Button has already been used, don't return any more presses
* until the button is released/re-pressed
*/
return KEY_NO_KEY;
}
/* Button has been pressed for the first time */
button = key_state;
return button;
}
/*---------------------------------------------------------------------------*/
/**
* \brief This function will start the ADC conversion and read the current
* converstion value to determine the button position.
*
* \retval KEY_ENTER Enter button has been pressed.
* \retval KEY_UP Up Button has been pressed.
* \retval KEY_RIGHT Right Button has been pressed.
* \retval KEY_LEFT Left Button has been pressed.
* \retval KEY_DOWN Down Button has been pressed.
* \retval KEY_NO_KEY No Button has been pressed.
*/
key_state_t
key_state_get(void)
{
int16_t reading;
/* Start the A/D conversion */
adc_conversion_start();
/* Wait for conversion to finish */
while ((reading = adc_result_get(ADC_ADJ_RIGHT)) == EOF )
;
/* Determine which button (if any) is being pressed */
if (!(ENTER_PORT & (1<<ENTER_PIN))){
return KEY_ENTER;
}
if (reading < 0x00A0){
return KEY_UP;
}
if (reading < 0x0180){
return KEY_RIGHT;
}
if (reading < 0x0280){
return KEY_LEFT;
}
if (reading < 0x0380){
return KEY_DOWN;
}
return KEY_NO_KEY;
}
/** \} */