Rev Author Line No. Line
1145 kaklik 1 /*! \file a2d.h \brief Analog-to-Digital converter function library. */
2 //*****************************************************************************
3 //
4 // File Name : 'a2d.h'
5 // Title : Analog-to-digital converter functions
6 // Author : Pascal Stang - Copyright (C) 2002
7 // Created : 4/08/2002
8 // Revised : 4/30/2002
9 // Version : 1.1
10 // Target MCU : Atmel AVR series
11 // Editor Tabs : 4
12 //
13 // This code is distributed under the GNU Public License
14 // which can be found at http://www.gnu.org/licenses/gpl.txt
15 //
16 /// \ingroup driver_avr
17 /// \defgroup a2d A/D Converter Function Library (a2d.c)
18 /// \code #include "a2d.h" \endcode
19 /// \par Overview
20 /// This library provides an easy interface to the analog-to-digital
21 /// converter available on many AVR processors. Updated to support
22 /// the ATmega128.
23 //
24 //****************************************************************************
25 //@{
26  
27 #ifndef A2D_H
28 #define A2D_H
29  
30 // defines
31  
32 // A2D clock prescaler select
33 // *selects how much the CPU clock frequency is divided
34 // to create the A2D clock frequency
35 // *lower division ratios make conversion go faster
36 // *higher division ratios make conversions more accurate
37 #define ADC_PRESCALE_DIV2 0x00 ///< 0x01,0x00 -> CPU clk/2
38 #define ADC_PRESCALE_DIV4 0x02 ///< 0x02 -> CPU clk/4
39 #define ADC_PRESCALE_DIV8 0x03 ///< 0x03 -> CPU clk/8
40 #define ADC_PRESCALE_DIV16 0x04 ///< 0x04 -> CPU clk/16
41 #define ADC_PRESCALE_DIV32 0x05 ///< 0x05 -> CPU clk/32
42 #define ADC_PRESCALE_DIV64 0x06 ///< 0x06 -> CPU clk/64
43 #define ADC_PRESCALE_DIV128 0x07 ///< 0x07 -> CPU clk/128
44 // default value
45 #define ADC_PRESCALE ADC_PRESCALE_DIV64
46 // do not change the mask value
47 #define ADC_PRESCALE_MASK 0x07
48  
49 // A2D voltage reference select
50 // *this determines what is used as the
51 // full-scale voltage point for A2D conversions
52 #define ADC_REFERENCE_AREF 0x00 ///< 0x00 -> AREF pin, internal VREF turned off
53 #define ADC_REFERENCE_AVCC 0x01 ///< 0x01 -> AVCC pin, internal VREF turned off
54 #define ADC_REFERENCE_RSVD 0x02 ///< 0x02 -> Reserved
55 #define ADC_REFERENCE_256V 0x03 ///< 0x03 -> Internal 2.56V VREF
56 // default value
57 #define ADC_REFERENCE ADC_REFERENCE_AVCC
58 // do not change the mask value
59 #define ADC_REFERENCE_MASK 0xC0
60  
61 // bit mask for A2D channel multiplexer
62 #define ADC_MUX_MASK 0x1F
63  
64 // channel defines (for reference and use in code)
65 // these channels supported by all AVRs with A2D
66 #define ADC_CH_ADC0 0x00
67 #define ADC_CH_ADC1 0x01
68 #define ADC_CH_ADC2 0x02
69 #define ADC_CH_ADC3 0x03
70 #define ADC_CH_ADC4 0x04
71 #define ADC_CH_ADC5 0x05
72 #define ADC_CH_ADC6 0x06
73 #define ADC_CH_ADC7 0x07
74 #define ADC_CH_122V 0x1E ///< 1.22V voltage reference
75 #define ADC_CH_AGND 0x1F ///< AGND
76 // these channels supported only in ATmega128
77 // differential with gain
78 #define ADC_CH_0_0_DIFF10X 0x08
79 #define ADC_CH_1_0_DIFF10X 0x09
80 #define ADC_CH_0_0_DIFF200X 0x0A
81 #define ADC_CH_1_0_DIFF200X 0x0B
82 #define ADC_CH_2_2_DIFF10X 0x0C
83 #define ADC_CH_3_2_DIFF10X 0x0D
84 #define ADC_CH_2_2_DIFF200X 0x0E
85 #define ADC_CH_3_2_DIFF200X 0x0F
86 // differential
87 #define ADC_CH_0_1_DIFF1X 0x10
88 #define ADC_CH_1_1_DIFF1X 0x11
89 #define ADC_CH_2_1_DIFF1X 0x12
90 #define ADC_CH_3_1_DIFF1X 0x13
91 #define ADC_CH_4_1_DIFF1X 0x14
92 #define ADC_CH_5_1_DIFF1X 0x15
93 #define ADC_CH_6_1_DIFF1X 0x16
94 #define ADC_CH_7_1_DIFF1X 0x17
95  
96 #define ADC_CH_0_2_DIFF1X 0x18
97 #define ADC_CH_1_2_DIFF1X 0x19
98 #define ADC_CH_2_2_DIFF1X 0x1A
99 #define ADC_CH_3_2_DIFF1X 0x1B
100 #define ADC_CH_4_2_DIFF1X 0x1C
101 #define ADC_CH_5_2_DIFF1X 0x1D
102  
103 // compatibility for new Mega processors
104 // ADCSR hack apparently no longer necessary in new AVR-GCC
105 #ifdef ADCSRA
106 #ifndef ADCSR
107 #define ADCSR ADCSRA
108 #endif
109 #endif
110 #ifdef ADATE
111 #define ADFR ADATE
112 #endif
113  
114 // function prototypes
115  
116 //! Initializes the A/D converter.
117 /// Turns ADC on and prepares it for use.
118 void a2dInit(void);
119  
120 //! Turn off A/D converter
121 void a2dOff(void);
122  
123 //! Sets the division ratio of the A/D converter clock.
124 /// This function is automatically called from a2dInit()
125 /// with a default value.
126 void a2dSetPrescaler(unsigned char prescale);
127  
128 //! Configures which voltage reference the A/D converter uses.
129 /// This function is automatically called from a2dInit()
130 /// with a default value.
131 void a2dSetReference(unsigned char ref);
132  
133 //! sets the a2d input channel
134 void a2dSetChannel(unsigned char ch);
135  
136 //! start a conversion on the current a2d input channel
137 void a2dStartConvert(void);
138  
139 //! return TRUE if conversion is complete
140 u08 a2dIsComplete(void);
141  
142 //! Starts a conversion on A/D channel# ch,
143 /// returns the 10-bit value of the conversion when it is finished.
144 unsigned short a2dConvert10bit(unsigned char ch);
145  
146 //! Starts a conversion on A/D channel# ch,
147 /// returns the 8-bit value of the conversion when it is finished.
148 unsigned char a2dConvert8bit(unsigned char ch);
149  
150 #endif
151 //@}