Arduino/build/shared/lib/avrlib/a2d.h

/*! \file a2d.h \brief Analog-to-Digital converter function library. */
//*****************************************************************************
//
// File Name	: 'a2d.h'
// Title		: Analog-to-digital converter functions
// Author		: Pascal Stang - Copyright (C) 2002
// Created		: 4/08/2002
// Revised		: 4/30/2002
// Version		: 1.1
// Target MCU	: Atmel AVR series
// Editor Tabs	: 4
//
// This code is distributed under the GNU Public License
//		which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************

#ifndef A2D_H
#define A2D_H

// defines

// A2D clock prescaler select
//		*selects how much the CPU clock frequency is divided
//		to create the A2D clock frequency
//		*lower division ratios make conversion go faster
//		*higher division ratios make conversions more accurate
#define ADC_PRESCALE_DIV2		0x00	///< 0x01,0x00 -> CPU clk/2
#define ADC_PRESCALE_DIV4		0x02	///< 0x02 -> CPU clk/4
#define ADC_PRESCALE_DIV8		0x03	///< 0x03 -> CPU clk/8
#define ADC_PRESCALE_DIV16		0x04	///< 0x04 -> CPU clk/16
#define ADC_PRESCALE_DIV32		0x05	///< 0x05 -> CPU clk/32
#define ADC_PRESCALE_DIV64		0x06	///< 0x06 -> CPU clk/64
#define ADC_PRESCALE_DIV128		0x07	///< 0x07 -> CPU clk/128
// default value
#define ADC_PRESCALE			ADC_PRESCALE_DIV64
// do not change the mask value
#define ADC_PRESCALE_MASK		0x07

// A2D voltage reference select
//		*this determines what is used as the
//		full-scale voltage point for A2D conversions
#define ADC_REFERENCE_AREF		0x00	///< 0x00 -> AREF pin, internal VREF turned off
#define ADC_REFERENCE_AVCC		0x01	///< 0x01 -> AVCC pin, internal VREF turned off
#define ADC_REFERENCE_RSVD		0x02	///< 0x02 -> Reserved
#define ADC_REFERENCE_256V		0x03	///< 0x03 -> Internal 2.56V VREF
// default value
#define ADC_REFERENCE			ADC_REFERENCE_AVCC
// do not change the mask value
#define ADC_REFERENCE_MASK		0xC0

// bit mask for A2D channel multiplexer
#define ADC_MUX_MASK			0x1F

// channel defines (for reference and use in code)
// these channels supported by all AVRs with A2D
#define ADC_CH_ADC0				0x00
#define ADC_CH_ADC1				0x01
#define ADC_CH_ADC2				0x02
#define ADC_CH_ADC3				0x03
#define ADC_CH_ADC4				0x04
#define ADC_CH_ADC5				0x05
#define ADC_CH_ADC6				0x06
#define ADC_CH_ADC7				0x07
#define ADC_CH_122V				0x1E	///< 1.22V voltage reference
#define ADC_CH_AGND				0x1F	///< AGND
// these channels supported only in ATmega128
// differential with gain
#define ADC_CH_0_0_DIFF10X		0x08
#define ADC_CH_1_0_DIFF10X		0x09
#define ADC_CH_0_0_DIFF200X		0x0A
#define ADC_CH_1_0_DIFF200X		0x0B
#define ADC_CH_2_2_DIFF10X		0x0C
#define ADC_CH_3_2_DIFF10X		0x0D
#define ADC_CH_2_2_DIFF200X		0x0E
#define ADC_CH_3_2_DIFF200X		0x0F
// differential
#define ADC_CH_0_1_DIFF1X		0x10
#define ADC_CH_1_1_DIFF1X		0x11
#define ADC_CH_2_1_DIFF1X		0x12
#define ADC_CH_3_1_DIFF1X		0x13
#define ADC_CH_4_1_DIFF1X		0x14
#define ADC_CH_5_1_DIFF1X		0x15
#define ADC_CH_6_1_DIFF1X		0x16
#define ADC_CH_7_1_DIFF1X		0x17

#define ADC_CH_0_2_DIFF1X		0x18
#define ADC_CH_1_2_DIFF1X		0x19
#define ADC_CH_2_2_DIFF1X		0x1A
#define ADC_CH_3_2_DIFF1X		0x1B
#define ADC_CH_4_2_DIFF1X		0x1C
#define ADC_CH_5_2_DIFF1X		0x1D

// compatibility for new Mega processors
// ADCSR hack apparently no longer necessary in new AVR-GCC
#ifdef ADCSRA
#ifndef ADCSR
	#define ADCSR	ADCSRA
#endif
#endif
#ifdef ADATE
	#define ADFR	ADATE
#endif

// function prototypes

//! Initializes the A/D converter
// (turns ADC on and prepares it for use)
void a2dInit(void);

//! Turn off A/D converter
void a2dOff(void);

//! sets the division ratio of the A/D converter clock
// this function is automatically called from a2dInit()
// with a default value
void a2dSetPrescaler(unsigned char prescale);

//! configures which voltage reference the A/D converter uses
// this function is automatically called from a2dInit()
// with a default value
void a2dSetReference(unsigned char ref);

//! sets the a2d input channel
void a2dSetChannel(unsigned char ch);

//! start a conversion on the current a2d input channel
void a2dStartConvert(void);

//! return TRUE if conversion is complete
u08 a2dIsComplete(void);

//! starts a conversion on A/D channel# ch,
// returns the 10-bit value of the conversion when it is finished
unsigned short a2dConvert10bit(unsigned char ch);

//! starts a conversion on A/D channel# ch,
// returns the 8-bit value of the conversion when it is finished
unsigned char a2dConvert8bit(unsigned char ch);

#endif