+++ /dev/null
-/**
- * \file
- * <!--
- * This file is part of BeRTOS.
- *
- * Bertos is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * As a special exception, you may use this file as part of a free software
- * library without restriction. Specifically, if other files instantiate
- * templates or use macros or inline functions from this file, or you compile
- * this file and link it with other files to produce an executable, this
- * file does not by itself cause the resulting executable to be covered by
- * the GNU General Public License. This exception does not however
- * invalidate any other reasons why the executable file might be covered by
- * the GNU General Public License.
- *
- * Copyright 2004, 2005 Develer S.r.l. (http://www.de+veler.com/)
- * All Rights Reserved.
- * -->
- *
- * \brief Driver for NTC (reads a temperature through an ADC)
- *
- * \version $Id$
- *
- * \author Giovanni Bajo <rasky@develer.com>
- * \author Francesco Sacchi <batt@develer.com>
- *
- *
- * This module handles an external NTC bound to an AD converter. As usual,
- * it relies on a low-level API (ntc_hw_*) (see below):
- *
- */
-
-/*#*
- *#* $Log$
- *#* Revision 1.2 2006/07/19 12:56:26 bernie
- *#* Convert to new Doxygen style.
- *#*
- *#* Revision 1.1 2005/11/04 17:59:47 bernie
- *#* Import into DevLib.
- *#*
- *#* Revision 1.1 2005/05/24 09:17:58 batt
- *#* Move drivers to top-level.
- *#*/
-
-#include <drv/ntc.h>
-#include <hw_ntc.h>
-#include <ntc_map.h>
-
-#include <cfg/debug.h>
-
-DB(bool ntc_initialized;)
-
-/**
- * Find in a table of values \a orig_table of size \a size, the index which
- * value is less or equal to \a val.
- *
- * \retval 0 When \a val is higher than the first table entry.
- * \retval size When \a val is lower than the last table entry.
- * \retval 1..size-1 When \a val is within the table.
- */
-static size_t upper_bound(const res_t *orig_table, size_t size, res_t val)
-{
- const res_t *table = orig_table;
-
- while (size)
- {
- size_t pos = size / 2;
- if (val > table[pos])
- size = pos;
- else
- {
- table += pos+1;
- size -= pos+1;
- }
- }
-
- return table - orig_table;
-}
-
-
-/**
- * Read the temperature for the NTC channel \a dev.
- * First read the resistence of the NTC through ntc_hw_read(), then,
- * for the conversion from resistance to temperature, since the formula
- * varies from device to device, we implemented a generic system using
- * a table of data which maps temperature (index) to resistance (data).
- * The range of the table (min/max temperature) and the step
- * (temperature difference between two consecutive elements of the table)
- * is variable and can be specified. Notice that values inbetween the
- * table elements are still possible as the library does a linear
- * interpolation using the actual calculated resistance to find out
- * the exact temperature.
- *
- * The low-level API provides a function to get access to a description
- * of the NTC (ntc_hw_getInfo()), including the resistance table.
- *
- */
-deg_t ntc_read(NtcDev dev)
-{
- const NtcHwInfo* hw = ntc_hw_getInfo(dev);
- const res_t* r = hw->resistances;
-
- float rx;
- size_t i;
- deg_t degrees;
-
- rx = ntc_hw_read(dev);
-
-
- i = upper_bound(r, hw->num_resistances, rx);
- ASSERT(i <= hw->num_resistances);
-
- if (i >= hw->num_resistances)
- return NTC_SHORT_CIRCUIT;
- else if (i == 0)
- return NTC_OPEN_CIRCUIT;
-
- /*
- * Interpolated value in 0.1 degrees multiplied by 10:
- * delta t step t
- * ---------- = ----------------
- * (rx - r[i]) (r[i-1] - r [i])
- */
- float tmp;
- tmp = 10 * hw->degrees_step * (rx - r[i]) / (r[i - 1] - r[i]);
-
- /*
- * degrees = integer part corresponding to the superior index
- * in the table multiplied by 10
- * - decimal part interpolated (already multiplied by 10)
- */
- degrees = (i * hw->degrees_step + hw->degrees_min) * 10 - (int)(tmp);
-
- //kprintf("dev= %d, I=%d, degrees = %d\n", dev, i , degrees);
-
- return degrees;
-}
-
-
-/**
- * Init NTC hardware.
- */
-void ntc_init(void)
-{
- NTC_HW_INIT;
- DB(ntc_initialized = true;)
-}
-
projects / bertos.git / blobdiff