Add driver for mpxx6115a pressure sensor.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@3044 38d2e660-2303-0410-9eaa-f027e97ec537

diff --git a/bertos/drv/mpxx6115a.h b/bertos/drv/mpxx6115a.h
new file mode 100644 (file)
index 0000000..9e3178a
--- /dev/null
+++ b/bertos/drv/mpxx6115a.h
@@ -0,0 +1,71 @@
+/**
+ * \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 2009 Develer S.r.l. (http://www.develer.com/)
+ *
+ * -->
+ *
+ * \brief Covert read voltage from MPXX6115A Pressure Sensor in hPascal value.
+ *
+ * \author Daniele Basile <asterix@develer.com>
+ *
+ */
+
+#ifndef DRV_MPXX6115A_H
+#define DRV_MPXX6115A_H
+
+#define MPXX6115A_DIV_CONST    0.009f
+#define MPXX6115A_ADD_CONST    0.095f
+
+
+/**
+ * Covert read voltage from MPXX6115A Pressure Sensor in hPascal value.
+ *
+ * The convertion formula may be consulted on costructor datasheet
+ * (see Freescale Semiconductor MP3H6115A, MPXAZ6115A).
+ *
+ * \param vout output voltage read from pin sensor.
+ * \param vref reference voltage that supplies the MPXX6115A sensor.
+ *
+ * \return interger value that represent measured pressure in hPascal.
+ *
+ * \note: To compute the pressure we use the Vout/Vref ratio, so
+ * these two values can be expressed in any unit, even adc levels.
+ *
+ */
+INLINE int16_t mpxx6115a_press(adcread_t vout,  adcread_t vref)
+{
+       float tmp;
+
+       tmp = (float)vout/(float)vref  + MPXX6115A_ADD_CONST;
+
+       // To return hpascal we should multiply by 10 because the ratio is in kpascal
+       return (int16_t)(tmp / MPXX6115A_DIV_CONST * 10);
+}
+
+#endif /* DRV_MPXX6115A_H */