Add some utility to read the temperature sensor on chip.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@4790 38d2e660-2303-0410-9eaa-f027e97ec537

diff --git a/boards/sam3x-ek/hw/hw_adc.h b/boards/sam3x-ek/hw/hw_adc.h
new file mode 100644 (file)
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+++ b/boards/sam3x-ek/hw/hw_adc.h
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+/**
+ * \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 2011 Develer S.r.l. (http://www.develer.com/)
+ * All Rights Reserved.
+ * -->
+ *
+ * \brief Some ADC utilis.
+ *
+ * \author Daniele Basile <asterix@develer.com>
+ */
+
+#ifndef HW_ADC_H
+#define HW_ADC_H
+
+#include <io/cm3.h>
+
+
+/*
+ * Enable temperature sensor
+ */
+INLINE void hw_enableTempRead(void)
+{
+
+       ADC_ACR = BV(ADC_TSON);
+}
+
+
+/*
+ * The VT voltage equals 0.8V at 27°C with a +/-15% accuracy.
+ * The VT output voltage linearly varies with a temperature slope dVT/dT = 2.65.
+ * So the formula is: x = (vol - 800) / 2.65 + 27.
+ */
+INLINE uint16_t hw_convertToDegree(uint16_t raw_temp)
+{
+       raw_temp = raw_temp * 3300 * 10 / 4096;
+       return ((raw_temp - 8000) * 100 / 265 + 270);
+}
+
+#endif /* HW_ADC_H */