223 lines
7.4 KiB
C
223 lines
7.4 KiB
C
/*
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* Copyright (c) 2008 Swedish Institute of Computer Science
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of the copyright holders nor the names of
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \file
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*
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* \brief
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* Driver for the on board temperature sensor.
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*
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* \author
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* Mike Vidales mavida404@gmail.com
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*
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*/
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#include "key.h"
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#include "temp.h"
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#include <avr/pgmspace.h>
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/**
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* \addtogroup lcd
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* \{
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*/
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/** Type used together with find_temp() to find temperature */
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typedef enum {
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TEMP_ZERO_OFFSET_CELCIUS = -15,
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TEMP_ZERO_OFFSET_FAHRENHEIT = 0
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} temp_zero_offset_t;
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#if defined( DOXYGEN )
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static uint16_t temp_table_celcius[];
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static uint16_t temp_table_fahrenheit[];
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#else /* !DOXYGEN */
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/** Celcius temperatures (ADC-value) from -15 to 60 degrees */
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static uint16_t temp_table_celcius[] PROGMEM = {
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923,917,911,904,898,891,883,876,868,860,851,843,834,825,815,
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806,796,786,775,765,754,743,732,720,709,697,685,673,661,649,
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636,624,611,599,586,574,562,549,537,524,512,500,488,476,464,
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452,440,429,418,406,396,385,374,364,354,344,334,324,315,306,
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297,288,279,271,263,255,247,240,233,225,219,212,205,199,193,
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187,
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};
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/** Fahrenheit temperatures (ADC-value) from 0 to 140 degrees */
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static uint16_t temp_table_fahrenheit[] PROGMEM = {
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938, 935, 932, 929, 926, 923, 920, 916, 913, 909, 906, 902, 898,
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894, 891, 887, 882, 878, 874, 870, 865, 861, 856, 851, 847, 842,
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837, 832, 827, 822, 816, 811, 806, 800, 795, 789, 783, 778, 772,
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766, 760, 754, 748, 742, 735, 729, 723, 716, 710, 703, 697, 690,
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684, 677, 670, 663, 657, 650, 643, 636, 629, 622, 616, 609, 602,
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595, 588, 581, 574, 567, 560, 553, 546, 539, 533, 526, 519, 512,
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505, 498, 492, 485, 478, 472, 465, 459, 452, 446, 439, 433, 426,
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420, 414, 408, 402, 396, 390, 384, 378, 372, 366, 360, 355, 349,
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344, 338, 333, 327, 322, 317, 312, 307, 302, 297, 292, 287, 282,
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277, 273, 268, 264, 259, 255, 251, 246, 242, 238, 234, 230, 226,
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222, 219, 215, 211, 207, 204, 200, 197, 194, 190, 187,
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};
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#endif /* !DOXYGEN */
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/** Flag indicating initialized or not */
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bool temp_initialized = false;
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/** \brief Find array index corresponding to input ADC value
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*
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* Returned array index is actual temperature + zero offset. To
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* get actual temperature, the zero offset (\ref temp_zero_offset_t)
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* has to be subtracted.
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*
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* \param[in] value Value to seracah for in table
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* \param[in] array Pointer to array in which to look for ADC value
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* \param[in] count Size of array
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*
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*
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* \return EOF on error
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*/
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static int find_temp(int16_t value, uint16_t* array, int count);
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/*---------------------------------------------------------------------------*/
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/**
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* \brief This will initialize the digital IO and adc channel for temperture readings.
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*
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* \retval 0 Place holder for returning status.
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*/
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int
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temp_init(void)
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{
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/* Disable the Digital IO for the analog readings. */
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DIDR0 |= (1 << ADC4D);
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/* Temp sens power pin as output */
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TEMP_DDR |= (1 << TEMP_BIT_PWR);
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/* Power off temp sensor */
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TEMP_PORT &= ~(1 << TEMP_BIT_PWR);
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/* Temp sens input, no pullup */
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TEMP_DDR &= ~(1 << TEMP_BIT_IN);
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TEMP_PORT &= ~(1 << TEMP_BIT_IN);
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temp_initialized = true;
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return 0;
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}
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/*---------------------------------------------------------------------------*/
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/**
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* \brief This will disable temperature readings by reseting the initialed flag.
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*/
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void
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temp_deinit(void)
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{
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temp_initialized = false;
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}
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/*---------------------------------------------------------------------------*/
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/**
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* \brief This will turn on the adc channel for reading the temp sensor.
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*
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* After the raw adc value is stored, it will be used to lookup a degree conversion
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* based on the tables for F or C.
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*
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* \param unit Used to determine what unit needs to be appended with the value.
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*
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* \return EOF This is an uninitialized adc error.
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* \retval temp The newly converted value in degrees F or C.
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*/
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int16_t
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temp_get(temp_unit_t unit)
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{
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int16_t res;
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int16_t temp;
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/* Return if temp sensor driver not initialized */
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if (temp_initialized == false) {
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return EOF;
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}
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/* Power up sensor */
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TEMP_PORT |= (1 << TEMP_BIT_PWR);
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/* Init ADC and measure */
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adc_init(ADC_CHAN_ADC4, ADC_TRIG_FREE_RUN, ADC_REF_AVCC, ADC_PS_128);
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adc_conversion_start();
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while ((res = adc_result_get(ADC_ADJ_RIGHT)) == EOF ){
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;
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}
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adc_deinit();
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/* Re-init the adc for buttons. */
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key_init();
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/* Power down sensor */
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TEMP_PORT &= ~(1 << TEMP_BIT_PWR);
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/* Get corresponding temperature from table */
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if (unit == TEMP_UNIT_CELCIUS) {
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temp = find_temp(res, temp_table_celcius, sizeof(temp_table_celcius)/sizeof(int)) + TEMP_ZERO_OFFSET_CELCIUS;
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} else /*unit == TEMP_UNIT_FAHRENHEIT*/{
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temp = find_temp(res, temp_table_fahrenheit, sizeof(temp_table_fahrenheit)/sizeof(int)) + TEMP_ZERO_OFFSET_FAHRENHEIT;
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}
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return temp;
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}
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/*---------------------------------------------------------------------------*/
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/**
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* \brief Find array index corresponding to input ADC value
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*
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* Returned array index is actual temperature + zero offset. To
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* get actual temperature, the zero offset (\ref temp_zero_offset_t)
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* has to be subtracted.
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*
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* \param[in] value Value to search for in table
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* \param[in] array Pointer to array in which to look for ADC value
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* \param[in] count Size of array
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*
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* \return EOF on error
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*/
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static int
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find_temp(int16_t value, uint16_t* array, int count)
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{
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int i = 0;
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int table_val = 0;
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do{
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table_val = pgm_read_word(&array[i]);
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if (table_val < value) {
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return i;
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}
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} while(++i<count);
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return EOF;
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}
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/** \} */
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