contiki/platform/avr-ravenlcd/temp.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
* Driver for the on board temperature sensor.
*
* \author
* Mike Vidales mavida404@gmail.com
*
*/
#include "key.h"
#include "temp.h"
#include "lcd.h"
/**
* \addtogroup lcd
* \{
*/
/** Type used together with find_temp() to find temperature */
typedef enum {
TEMP_ZERO_OFFSET_CELCIUS = -15,
TEMP_ZERO_OFFSET_FAHRENHEIT = 0
} temp_zero_offset_t;
#if defined( DOXYGEN )
static uint16_t temp_table_celcius[];
static uint16_t temp_table_fahrenheit[];
#else /* !DOXYGEN */
/** Celcius temperatures (ADC-value) from -15 to 60 degrees */
static uint16_t temp_table_celcius[] PROGMEM = {
923,917,911,904,898,891,883,876,868,860,851,843,834,825,815,
806,796,786,775,765,754,743,732,720,709,697,685,673,661,649,
636,624,611,599,586,574,562,549,537,524,512,500,488,476,464,
452,440,429,418,406,396,385,374,364,354,344,334,324,315,306,
297,288,279,271,263,255,247,240,233,225,219,212,205,199,193,
187,
};
/** Fahrenheit temperatures (ADC-value) from 0 to 140 degrees */
static uint16_t temp_table_fahrenheit[] PROGMEM = {
938, 935, 932, 929, 926, 923, 920, 916, 913, 909, 906, 902, 898,
894, 891, 887, 882, 878, 874, 870, 865, 861, 856, 851, 847, 842,
837, 832, 827, 822, 816, 811, 806, 800, 795, 789, 783, 778, 772,
766, 760, 754, 748, 742, 735, 729, 723, 716, 710, 703, 697, 690,
684, 677, 670, 663, 657, 650, 643, 636, 629, 622, 616, 609, 602,
595, 588, 581, 574, 567, 560, 553, 546, 539, 533, 526, 519, 512,
505, 498, 492, 485, 478, 472, 465, 459, 452, 446, 439, 433, 426,
420, 414, 408, 402, 396, 390, 384, 378, 372, 366, 360, 355, 349,
344, 338, 333, 327, 322, 317, 312, 307, 302, 297, 292, 287, 282,
277, 273, 268, 264, 259, 255, 251, 246, 242, 238, 234, 230, 226,
222, 219, 215, 211, 207, 204, 200, 197, 194, 190, 187,
};
#endif /* !DOXYGEN */
/** Flag indicating initialized or not */
bool temp_initialized = false;
/** \brief Find array index corresponding to input ADC value
*
* Returned array index is actual temperature + zero offset. To
* get actual temperature, the zero offset (\ref temp_zero_offset_t)
* has to be subtracted.
*
* \param[in] value Value to seracah for in table
* \param[in] array Pointer to array in which to look for ADC value
* \param[in] count Size of array
*
*
* \return EOF on error
*/
static int find_temp(int16_t value, uint16_t* array, int count);
/*---------------------------------------------------------------------------*/
/**
* \brief This will initialize the digital IO and adc channel for temperture readings.
*
* \retval 0 Place holder for returning status.
*/
int
temp_init(void)
{
/* Disable the Digital IO for the analog readings. */
DIDR0 |= (1 << ADC4D);
/* Temp sens power pin as output */
TEMP_DDR |= (1 << TEMP_BIT_PWR);
/* Power off temp sensor */
TEMP_PORT &= ~(1 << TEMP_BIT_PWR);
/* Temp sens input, no pullup */
TEMP_DDR &= ~(1 << TEMP_BIT_IN);
TEMP_PORT &= ~(1 << TEMP_BIT_IN);
temp_initialized = true;
return 0;
}
/*---------------------------------------------------------------------------*/
/**
* \brief This will disable temperature readings by reseting the initialed flag.
*/
void
temp_deinit(void)
{
temp_initialized = false;
}
/*---------------------------------------------------------------------------*/
/**
* \brief This will turn on the adc channel for reading the temp sensor.
*
* After the raw adc value is stored, it will be used to lookup a degree conversion
* based on the tables for F or C.
*
* \param unit Used to determine what unit needs to be appended with the value.
*
* \return EOF This is an uninitialized adc error.
* \retval temp The newly converted value in degrees F or C.
*/
int16_t
temp_get(temp_unit_t unit)
{
int16_t res;
int16_t temp;
/* Return if temp sensor driver not initialized */
if (temp_initialized == false) {
return EOF;
}
/* Power up sensor */
TEMP_PORT |= (1 << TEMP_BIT_PWR);
/* Init ADC and measure */
adc_init(ADC_CHAN_ADC4, ADC_TRIG_FREE_RUN, ADC_REF_AVCC, ADC_PS_128);
adc_conversion_start();
while ((res = adc_result_get(ADC_ADJ_RIGHT)) == EOF ){
;
}
adc_deinit();
/* Re-init the adc for buttons. */
key_init();
/* Power down sensor */
TEMP_PORT &= ~(1 << TEMP_BIT_PWR);
/* Get corresponding temperature from table */
if (unit == TEMP_UNIT_CELCIUS) {
temp = find_temp(res, temp_table_celcius, sizeof(temp_table_celcius)/sizeof(int)) + TEMP_ZERO_OFFSET_CELCIUS;
} else /*unit == TEMP_UNIT_FAHRENHEIT*/{
temp = find_temp(res, temp_table_fahrenheit, sizeof(temp_table_fahrenheit)/sizeof(int)) + TEMP_ZERO_OFFSET_FAHRENHEIT;
}
return temp;
}
/*---------------------------------------------------------------------------*/
/**
* \brief Find array index corresponding to input ADC value
*
* Returned array index is actual temperature + zero offset. To
* get actual temperature, the zero offset (\ref temp_zero_offset_t)
* has to be subtracted.
*
* \param[in] value Value to search for in table
* \param[in] array Pointer to array in which to look for ADC value
* \param[in] count Size of array
*
* \return EOF on error
*/
static int
find_temp(int16_t value, uint16_t* array, int count)
{
int i = 0;
int table_val = 0;
do{
table_val = pgm_read_word(&array[i]);
if (table_val < value) {
return i;
}
} while(++i<count);
return EOF;
}
/** \} */