ADC.h 8.76 KB
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/*
             LUFA Library
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     Copyright (C) Dean Camera, 2010.
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  dean [at] fourwalledcubicle [dot] com
      www.fourwalledcubicle.com
*/

/*
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  Copyright 2010  Dean Camera (dean [at] fourwalledcubicle [dot] com)
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  Permission to use, copy, modify, distribute, and sell this 
  software and its documentation for any purpose is hereby granted
  without fee, provided that the above copyright notice appear in 
  all copies and that both that the copyright notice and this
  permission notice and warranty disclaimer appear in supporting 
  documentation, and that the name of the author not be used in 
  advertising or publicity pertaining to distribution of the 
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  software without specific, written prior permission.

  The author disclaim all warranties with regard to this
  software, including all implied warranties of merchantability
  and fitness.  In no event shall the author be liable for any
  special, indirect or consequential damages or any damages
  whatsoever resulting from loss of use, data or profits, whether
  in an action of contract, negligence or other tortious action,
  arising out of or in connection with the use or performance of
  this software.
*/

/** \file
 *
 *  ADC driver for the AT90USB1287, AT90USB1286, AT90USB647, AT90USB646, ATMEGA16U4 and ATMEGA32U4 AVRs.
 *
 *  \note This file should not be included directly. It is automatically included as needed by the ADC driver
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 *        dispatch header located in LUFA/Drivers/Peripheral/ADC.h.
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 */

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/** \ingroup Group_ADC
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 *  @defgroup Group_ADC_AVRU4U6U7 Series U4, U6 and U7 Model ADC Driver
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 *
 *  @{
 */
 
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#ifndef __ADC_AVRU4U6U7_H__
#define __ADC_AVRU4U6U7_H__
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	/* Includes: */
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		#include "../../../Common/Common.h"
		
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		#include <avr/io.h>
		#include <stdbool.h>
		
	/* Enable C linkage for C++ Compilers: */
		#if defined(__cplusplus)
			extern "C" {
		#endif

	/* Preprocessor Checks: */
		#if !defined(INCLUDE_FROM_ADC_H)
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			#error Do not include this file directly. Include LUFA/Drivers/Peripheral/ADC.h instead.
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		#endif

	/* Public Interface - May be used in end-application: */
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		/* Macros: */			
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			/** Reference mask, for using the voltage present at the AVR's AREF pin for the ADC reference. */
			#define  ADC_REFERENCE_AREF              0

			/** Reference mask, for using the voltage present at the AVR's AVCC pin for the ADC reference. */
			#define  ADC_REFERENCE_AVCC              (1 << REFS0)

			/** Reference mask, for using the internally generated 2.56V reference voltage as the ADC reference. */
			#define  ADC_REFERENCE_INT2560MV         ((1 << REFS1)| (1 << REFS0))
			
			/** Left-adjusts the 10-bit ADC result, so that the upper 8 bits of the value returned by the
			 *  ADC_GetResult() macro contain the 8 most significant bits of the result. */
			#define  ADC_LEFT_ADJUSTED               (1 << ADLAR)

			/** Right-adjusts the 10-bit ADC result, so that the lower 8 bits of the value returned by the
			 *  ADC_GetResult() macro contain the 8 least significant bits of the result. */
			#define  ADC_RIGHT_ADJUSTED              (0 << ADLAR)
			
			/** Sets the ADC mode to free running, so that conversions take place continuously as fast as the ADC
			 *  is capable of at the given input clock speed. */
			#define  ADC_FREE_RUNNING                (1 << ADATE)

			/** Sets the ADC mode to single conversion, so that only a single conversion will take place before
			 *  the ADC returns to idle. */
			#define  ADC_SINGLE_CONVERSION           (0 << ADATE)
			
			/** Sets the ADC input clock to prescale by a factor of 2 the AVR's system clock. */
			#define  ADC_PRESCALE_2                  (1 << ADPS0)

			/** Sets the ADC input clock to prescale by a factor of 4 the AVR's system clock. */
			#define  ADC_PRESCALE_4                  (1 << ADPS1)

			/** Sets the ADC input clock to prescale by a factor of 8 the AVR's system clock. */
			#define  ADC_PRESCALE_8                  ((1 << ADPS0) | (1 << ADPS1))

			/** Sets the ADC input clock to prescale by a factor of 16 the AVR's system clock. */
			#define  ADC_PRESCALE_16                 (1 << ADPS2)

			/** Sets the ADC input clock to prescale by a factor of 32 the AVR's system clock. */
			#define  ADC_PRESCALE_32                 ((1 << ADPS2) | (1 << ADPS0))

			/** Sets the ADC input clock to prescale by a factor of 64 the AVR's system clock. */
			#define  ADC_PRESCALE_64                 ((1 << ADPS2) | (1 << ADPS1))

			/** Sets the ADC input clock to prescale by a factor of 128 the AVR's system clock. */
			#define  ADC_PRESCALE_128                ((1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0))

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		/* Pseudo-Function Macros: */
			#if defined(__DOXYGEN__)
				/** Initializes the ADC, ready for conversions. This must be called before any other ADC operations.
				 *  The "mode" parameter should be a mask comprised of a conversion mode (free running or single) and
				 *  prescaler masks.
				 *
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				 *  \param[in] Mode  Mask of ADC settings, including adjustment, prescale, mode and reference
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				 */
				static inline void ADC_Init(uint8_t Mode);
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				/** Turns off the ADC. If this is called, any further ADC operations will require a call to
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				 *  \ref ADC_Init() before the ADC can be used again.
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				 */
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				static inline void ADC_ShutDown(void);
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				/** Indicates if the ADC is currently enabled.
				 *
				 *  \return Boolean true if the ADC subsystem is currently enabled, false otherwise.
				 */
				static inline bool ADC_GetStatus(void);
				
				/** Indicates if the current ADC conversion is completed, or still in progress.
				 *
				 *  \return Boolean false if the reading is still taking place, or true if the conversion is
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				 *          complete and ready to be read out with \ref ADC_GetResult()
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				 */
				static inline bool ADC_IsReadingComplete(void);
				
				/** Retrieves the conversion value of the last completed ADC conversion.
				 *
				 *  \return The result of the last ADC conversion
				 */
				static inline uint16_t ADC_GetResult(void);
			#else
				#define  ADC_Init(mode)          MACROS{ ADCSRA = ((1 << ADEN) | mode);         }MACROE

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				#define  ADC_ShutDown()          MACROS{ ADCSRA = 0;                            }MACROE
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				#define  ADC_GetStatus()               ((ADCSRA & (1 << ADEN)) ? true : false)

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				#define  ADC_IsReadingComplete()        (ADCSRA & (1 << ADSC))
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				#define  ADC_GetResult()                 ADC			
			#endif
			
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		/* Inline Functions: */
			/** Configures the given ADC channel, ready for ADC conversions. This function sets the
			 *  associated port pin as an input and disables the digital portion of the I/O to reduce
			 *  power consumption.
			 *
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			 *  \param[in] Channel  ADC channel number to set up for conversions
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			 */
			static inline void ADC_SetupChannel(const uint8_t Channel)
			{
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				#if (defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB646__) || \
					 defined(__AVR_AT90USB1287__) || defined(__AVR_AT90USB647__) || \
					 defined(__AVR_ATmega32U6__))				
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				DDRF  &= ~(1 << Channel);
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				DIDR0 |=  (1 << Channel);
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				#elif (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
				if (Channel < 8)
				{
					DDRF  &= ~(1 << Channel);
					DIDR0 |=  (1 << Channel);
				}
				else if (Channel == 8)
				{
					DDRD  &= ~(1 << 4);
					DIDR2 |=  (1 << 0);
				}
				else if (Channel < 11)
				{
					DDRD  &= ~(1 << (Channel - 3));
					DIDR2 |=  (1 << (Channel - 8));
				}
				else
				{
					DDRB  &= ~(1 << (Channel - 7));
					DIDR2 |=  (1 << (Channel - 8));
				}
				#endif
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			}
			
			/** Starts the reading of the given channel, but does not wait until the conversion has completed.
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			 *  Once executed, the conversion status can be determined via the \ref ADC_IsReadingComplete() macro and
			 *  the result read via the \ref ADC_GetResult() macro.
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			 *
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			 *  \param[in] MUXMask  Mask comprising of an ADC channel number, reference mask and adjustment mask
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			 */
			static inline void ADC_StartReading(const uint8_t MUXMask)
			{
				ADMUX = MUXMask;
			
				ADCSRA |= (1 << ADSC);
			}

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			/** Performs a complete single reading from channel, including a polling spin-loop to wait for the
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			 *  conversion to complete, and the returning of the converted value.
			 *
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			 *  \param[in] MUXMask  Mask comprising of an ADC channel number, reference mask and adjustment mask
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			 */
			static inline uint16_t ADC_GetChannelReading(const uint8_t MUXMask) ATTR_WARN_UNUSED_RESULT;
			static inline uint16_t ADC_GetChannelReading(const uint8_t MUXMask)
			{
				ADC_StartReading(MUXMask);
	
				while (!(ADC_IsReadingComplete()));
	
				return ADC_GetResult();
			}

	/* Disable C linkage for C++ Compilers: */
		#if defined(__cplusplus)
			}
		#endif
		
#endif
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/** @} */