1 files changed, 245 insertions, 0 deletions
diff --git a/bsps/arm/lpc176x/start/adc.c b/bsps/arm/lpc176x/start/adc.c
new file mode 100755
index 0000000000..7098166718
--- /dev/null
+++ b/bsps/arm/lpc176x/start/adc.c
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+/**
+ * @file adc.c
+ *
+ * @ingroup lpc176x
+ *
+ * @brief ADC library for the lpc176x bsp.
+ */
+
+/*
+ * Copyright (c) 2014 Taller Technologies.
+ *
+ * @author  Diaz Marcos (marcos.diaz@tallertechnologies.com)
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+#include <rtems/status-checks.h>
+#include <bsp/adc.h>
+#include <bsp/adc-defs.h>
+
+static lpc176x_adc_device *const adc_device =
+  (lpc176x_adc_device *) AD0_BASE_ADDR;
+
+static const lpc176x_adc_pin_map adc_pinmap[ ADC_DEVICES_COUNT ] =
+{
+  {
+    .pin_number = 23u,
+    .pin_function = LPC176X_PIN_FUNCTION_01
+  },
+  {
+    .pin_number = 24u,
+    .pin_function = LPC176X_PIN_FUNCTION_01
+  },
+  {
+    .pin_number = 25u,
+    .pin_function = LPC176X_PIN_FUNCTION_01
+  },
+  {
+    .pin_number = 26u,
+    .pin_function = LPC176X_PIN_FUNCTION_01
+  },
+  {
+    .pin_number = 62u,
+    .pin_function = LPC176X_PIN_FUNCTION_11
+  },
+  {
+    .pin_number = 63u,
+    .pin_function = LPC176X_PIN_FUNCTION_11
+  },
+  {
+    .pin_number = 3u,
+    .pin_function = LPC176X_PIN_FUNCTION_10
+  },
+  {
+    .pin_number = 2u,
+    .pin_function = LPC176X_PIN_FUNCTION_10
+  }
+};
+
+/**
+ * @brief Checks for a valid pin number for an ADC
+ *
+ * @param pin_number The pin to check
+ * @param adc_number The returned ADC device corresponding to that pin.
+ *
+ * @return true if valid, false otherwise.
+ */
+static bool valid_pin_number (
+  const lpc176x_pin_number pin_number,
+  lpc176x_adc_number *const adc_number
+  )
+{
+  bool found = false;
+  lpc176x_adc_number adc_device = ADC_0;
+
+  while (!found && (adc_device < ADC_DEVICES_COUNT))
+  {
+    if (adc_pinmap[adc_device].pin_number == pin_number)
+    {
+      *adc_number = adc_device;
+      found = true;
+    }
+    ++adc_device;
+  }
+
+  return found;
+}
+
+/**
+ * @brief Turns on the device and sets its clock divisor.
+ *
+ */
+static void turn_on_and_set_clkdiv( void )
+{
+  const uint32_t clkdiv = LPC176X_CCLK / ( LPC176X_PCLKDIV * MAX_ADC_CLK );
+
+  adc_device->ADCR = ADC_CR_PDN | ADC_CR_CLKDIV( clkdiv );
+}
+
+rtems_status_code adc_open( const lpc176x_pin_number pin_number )
+{
+  rtems_status_code sc = RTEMS_INVALID_NUMBER;
+  lpc176x_adc_number adc_number = 0;
+  if ( valid_pin_number( pin_number, &adc_number ) ) {
+    sc =
+      lpc176x_module_enable( LPC176X_MODULE_ADC, LPC176X_MODULE_PCLK_DEFAULT );
+    RTEMS_CHECK_SC( sc, "enable adc module" );
+
+    turn_on_and_set_clkdiv();
+    lpc176x_pin_select( adc_pinmap[ adc_number ].pin_number,
+      adc_pinmap[ adc_number ].pin_function );
+    lpc176x_pin_set_mode( adc_pinmap[ adc_number ].pin_number,
+      LPC176X_PIN_MODE_NONE );
+  }
+
+  return sc;
+}
+
+rtems_status_code adc_close( void )
+{
+  adc_device->ADCR &= ~ADC_CR_PDN;
+
+  return lpc176x_module_disable( LPC176X_MODULE_ADC );
+}
+
+/**
+ * @brief Starts the conversion for the given channel.
+ *
+ * @param number The channel to start the conversion.
+ */
+static inline void start_conversion( const lpc176x_adc_number number )
+{
+  adc_device->ADCR =
+    ADC_CR_SEL_SET( adc_device->ADCR, ( 1 << number ) ) | ADC_CR_START_NOW;
+}
+
+/**
+ * @brief Stops the conversion.
+ *
+ */
+static inline void stop_conversion( void )
+{
+  adc_device->ADCR &= ~ADC_CR_START_NOW;
+}
+
+/**
+ * @brief Gets float percentage of the result of a conversion.
+ *
+ * @param data The result of a conversion.
+ * @return A float percentage (between 0.0f and 1.0f).
+ */
+static inline float get_float( const uint32_t data )
+{
+  return ( (float) data / (float) ADC_RANGE );
+}
+
+
+/**
+ * @brief Reads the ADC value for the given ADC number.
+ *
+ * @param adc_number Which ADC device read.
+ * @return The read value.
+ */
+static uint32_t read( const lpc176x_adc_number adc_number )
+{
+  uint32_t data;
+
+  start_conversion( adc_number );
+
+  do {
+    data = adc_device->ADGDR;
+  } while ( !ADC_DATA_CONVERSION_DONE( data ) );
+
+  stop_conversion();
+
+  return ADC_DR_VALUE( data );
+}
+
+/**
+ * @brief Checks if the passed parameters are ordered from lowest
+ *  to highest.
+ *
+ *  @param a The suggested lowest value.
+ *  @param b The suggested middle value.
+ *  @param c The suggested highest value.
+ *  @return  True if it is in the right order, false otherwise.
+ */
+static inline bool lowest_to_highest_ordered(
+  const uint32_t a,
+  const uint32_t b,
+  const uint32_t c
+)
+{
+  return ( ( a <= b ) && ( b <= c ) );
+}
+
+/**
+ * @brief Gets median value from the three passed parameters.
+ *
+ * @param  a The first parameter.
+ * @param  b The second parameter.
+ * @param  c The third parameter.
+ *
+ * @return  The median of the three parameters.
+ */
+static uint32_t get_median(
+  const uint32_t a,
+  const uint32_t b,
+  const uint32_t c
+)
+{
+  uint32_t median;
+
+  if ( lowest_to_highest_ordered( a, b, c)
+              || lowest_to_highest_ordered( c, b, a ) ) {
+    median = b;
+  } else if ( lowest_to_highest_ordered( b, a, c )
+              || lowest_to_highest_ordered( c, a, b ) ) {
+    median = a;
+  } else {
+    median = c;
+  }
+
+  return median;
+}
+
+rtems_status_code adc_read(
+  const lpc176x_pin_number pin_number ,
+  float *const             result
+)
+{
+  rtems_status_code sc = RTEMS_INVALID_NUMBER;
+  lpc176x_adc_number adc_number = 0;
+  if ( valid_pin_number( pin_number, &adc_number ) ) {
+    const uint32_t first = read( adc_number );
+    const uint32_t second = read( adc_number );
+    const uint32_t third = read( adc_number );
+    const uint32_t median = get_median( first, second, third );
+    *result = get_float( median );
+    sc = RTEMS_SUCCESSFUL;
+  }
+
+  return sc;
+}