sys: s/adc_util/analog_util/ and added DAC mapping

sys/analog_util/adc_util.c

@@ -7,7 +7,7 @@
  */
 
 /**
- * @ingroup     sys_adc_util
+ * @ingroup     sys_analog_util
  * @{
  *
  * @file
@@ -18,7 +18,7 @@
  * @}
  */
 
-#include "adc_util.h"
+#include "analog_util.h"
 
 /* keep a max value to ADC resolution mapping for quick access in the ROM */
 static const int val_max[] = {
@@ -28,7 +28,7 @@ static const int val_max[] = {
     [ADC_RES_12BIT] =   0x0fff,
     [ADC_RES_14BIT] =   0x3fff,
     [ADC_RES_16BIT] =   0xffff
-}
+};
 
 int adc_util_map(int sample, adc_res_t res, int min, int max)
 {

sys/analog_util/dac_util.c

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2015 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     sys_analog_util
+ * @{
+ *
+ * @file
+ * @brief       DAC utility function implementation
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <limits.h>
+
+#include "analog_util.h"
+
+uint16_t dac_util_map(int value, int min, int max)
+{
+    return (uint16_t)((value - min) * UINT16_MAX) / (max - min);
+}
+
+uint16_t dac_util_mapf(float value, float min, float max)
+{
+    return (uint16_t)(((value - min) * UINT16_MAX) / (max - min));
+}

sys/include/analog_util.h

@@ -7,19 +7,19 @@
  */
 
 /**
- * @defgroup    sys_adc_util ADC utilities
+ * @defgroup    sys_analog_util Analog data conversion utilities
  * @ingroup     sys
- * @brief       Utility functions for handling ADC samples
+ * @brief       Utility functions for converting analog data samples
  *
  * @{
  * @file
- * @brief       ADC utility function interfaces
+ * @brief       Analog utility function interfaces
  *
  * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
  */
 
-#ifndef ADC_UTIL_H
-#define ADC_UTIL_H
+#ifndef ANALOG_UTIL_H
+#define ANALOG_UTIL_H
 
 #include "periph/adc.h"
 
@@ -59,9 +59,36 @@ int adc_util_map(int sample, adc_res_t res, int min, int max);
  */
 float adc_util_mapf(int sample, adc_res_t res, float min, float max);
 
+/**
+ * @brief   Map a value out of the given range to a 16-bit unsigned int
+ *
+ * The min value is assumed to be smaller than max value and value is assumed
+ * to be between min and max.
+ *
+ * @param[in] value        value to map to a DAC set value
+ * @param[in] min          the lower bound of the source interval
+ * @param[in] max          the upper bound of the source interval
+ *
+ * @return                 the mapped value
+ */
+uint16_t dac_util_map(int value, int min, int max);
+
+/**
+ * @brief Helper function to map a given float value range to a valid DAC value.
+ *
+ * @see dac_util_map
+ *
+ * @param[in] value        value to map to a DAC set value
+ * @param[in] min          the lower bound of the source interval
+ * @param[in] max          the upper bound of the source interval
+ *
+ * @return                 the mapped value
+ */
+uint16_t dac_util_mapf(float value, float min, float max);
+
 #ifdef __cplusplus
 }
 #endif
 
-#endif /* ADC_UTIL_H */
+#endif /* ANALOG_UTIL_H */
 /** @} */