81 lines
2.7 KiB
C
81 lines
2.7 KiB
C
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/**
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* \file
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* <!--
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* This file is part of BeRTOS.
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*
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* Bertos is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* As a special exception, you may use this file as part of a free software
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* library without restriction. Specifically, if other files instantiate
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* templates or use macros or inline functions from this file, or you compile
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* this file and link it with other files to produce an executable, this
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* file does not by itself cause the resulting executable to be covered by
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* the GNU General Public License. This exception does not however
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* invalidate any other reasons why the executable file might be covered by
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* the GNU General Public License.
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*
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* Copyright 2009 Develer S.r.l. (http://www.develer.com/)
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*
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* -->
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*
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* \brief MPXX6115A Pressure Sensor convert formula.
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*
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* This module convert read voltage value from MPXX6115A
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* pressure sensor into hPascal value unit.
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*
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* \author Daniele Basile <asterix@develer.com>
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*
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* $WIZ$ module_name = "mpxx6115a"
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* $WIZ$ module_depends = "adc"
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* $WIZ$ module_configuration = ""
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* $WIZ$ module_hw = ""
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*/
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#ifndef DRV_MPXX6115A_H
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#define DRV_MPXX6115A_H
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#include <drv/adc.h>
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#define MPXX6115A_DIV_CONST 0.009f
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#define MPXX6115A_ADD_CONST 0.095f
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/**
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* Convert read voltage from MPXX6115A Pressure Sensor in hPascal value.
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*
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* The conversion formula may be consulted on constructor datasheet
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* (see Freescale Semiconductor MP3H6115A, MPXAZ6115A).
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*
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* \param vout output voltage read from pin sensor.
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* \param vref reference voltage that supplies the MPXX6115A sensor.
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*
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* \return integer value that represent measured pressure in hPascal.
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*
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* \note: To compute the pressure we use the Vout/Vref ratio, so
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* these two values can be expressed in any unit, even ADC levels.
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*
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*/
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INLINE int16_t mpxx6115a_press(adcread_t vout, adcread_t vref)
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{
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float tmp;
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tmp = (float)vout/(float)vref + MPXX6115A_ADD_CONST;
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// To return hpascal we should multiply by 10 because the ratio is in kpascal
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return (int16_t)(tmp / MPXX6115A_DIV_CONST * 10);
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}
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#endif /* DRV_MPXX6115A_H */
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