229 lines
12 KiB
C++
229 lines
12 KiB
C++
#ifndef _DDS_H_
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#define _DDS_H_
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#include <avr/pgmspace.h>
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// Use pin 3 for PWM? If not defined, use pin 11
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// Quality on pin 3 is higher than on 11, as it can be clocked faster
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// when the COMPARATOR_BITS value is less than 8
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#define DDS_PWM_PIN_3
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// Normally, we turn on timer2 and timer1, and have ADC sampling as our clock
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// Define this to only use Timer2, and not start the ADC clock
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// #define DDS_USE_ONLY_TIMER2
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// Use a short (16 bit) accumulator. Phase accuracy is reduced, but speed
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// is increased, along with a reduction in memory use.
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#define SHORT_ACCUMULATOR
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#ifdef SHORT_ACCUMULATOR
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#define ACCUMULATOR_BITS 16
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typedef uint16_t ddsAccumulator_t;
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#else
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#define ACCUMULATOR_BITS 32
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typedef uint32_t ddsAccumulator_t;
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#endif
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// If defined, the timer will idle at 50% duty cycle
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// This leaves it floating in the centre of the PWM/DAC voltage range
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#define DDS_IDLE_HIGH
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// Select how fast the PWM is, at the expense of level accuracy.
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// A faster PWM rate will make for easier filtering of the output wave,
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// while a slower one will allow for more accurate voltage level outputs,
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// but will increase the filtering requirements on the output.
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// 8 = 62.5kHz PWM
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// 7 = 125kHz PWM
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// 6 = 250kHz PWM
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#ifdef DDS_PWM_PIN_3
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#define COMPARATOR_BITS 6
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#else // When using pin 11, we always want 8 bits
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#define COMPARATOR_BITS 8
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#endif
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// This is how often we'll perform a phase advance, as well as ADC sampling
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// rate. The higher this value, the smoother the output wave will be, at the
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// expense of CPU time. It maxes out around 62000 (TBD)
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// May be overridden in the sketch to improve performance
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#ifndef DDS_REFCLK_DEFAULT
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#define DDS_REFCLK_DEFAULT 9600
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#endif
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// As each Arduino crystal is a little different, this can be fine tuned to
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// provide more accurate frequencies. Adjustments in the range of hundreds
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// is a good start.
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#ifndef DDS_REFCLK_OFFSET
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#define DDS_REFCLK_OFFSET 0
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#endif
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#ifdef DDS_USE_ONLY_TIMER2
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// TODO: Figure out where this clock value is generated from
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#define DDS_REFCLK_DEFAULT (62500/4)
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#endif
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// Output some of the calculations and information about the DDS over serial
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//#define DDS_DEBUG_SERIAL
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// When defined, use the 1024 element sine lookup table. This improves phase
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// accuracy, at the cost of more flash and CPU requirements.
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// #define DDS_TABLE_LARGE
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#ifdef DDS_TABLE_LARGE
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// How many bits to keep from the accumulator to look up in this table
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#define ACCUMULATOR_BIT_SHIFT (ACCUMULATOR_BITS-10)
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static const int8_t ddsSineTable[1024] PROGMEM = {
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0, 0, 1, 2, 3, 3, 4, 5, 6, 7, 7, 8, 9, 10, 10, 11, 12, 13, 13, 14, 15, 16, 17, 17, 18, 19, 20, 20, 21, 22, 23, 24,
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24, 25, 26, 27, 27, 28, 29, 30, 30, 31, 32, 33, 33, 34, 35, 36, 36, 37, 38, 39, 39, 40, 41, 42, 42, 43, 44, 44, 45, 46, 47, 47,
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48, 49, 50, 50, 51, 52, 52, 53, 54, 55, 55, 56, 57, 57, 58, 59, 59, 60, 61, 61, 62, 63, 63, 64, 65, 65, 66, 67, 67, 68, 69, 69,
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70, 71, 71, 72, 73, 73, 74, 75, 75, 76, 76, 77, 78, 78, 79, 79, 80, 81, 81, 82, 82, 83, 84, 84, 85, 85, 86, 87, 87, 88, 88, 89,
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89, 90, 90, 91, 91, 92, 93, 93, 94, 94, 95, 95, 96, 96, 97, 97, 98, 98, 99, 99, 100, 100, 101, 101, 102, 102, 102, 103, 103, 104, 104, 105,
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105, 106, 106, 106, 107, 107, 108, 108, 108, 109, 109, 110, 110, 110, 111, 111, 112, 112, 112, 113, 113, 113, 114, 114, 114, 115, 115, 115, 116, 116, 116, 117,
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117, 117, 117, 118, 118, 118, 119, 119, 119, 119, 120, 120, 120, 120, 121, 121, 121, 121, 121, 122, 122, 122, 122, 123, 123, 123, 123, 123, 123, 124, 124, 124,
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124, 124, 124, 124, 125, 125, 125, 125, 125, 125, 125, 125, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126,
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127, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 126, 125, 125, 125, 125, 125, 125, 125, 125, 124, 124, 124,
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124, 124, 124, 124, 123, 123, 123, 123, 123, 123, 122, 122, 122, 122, 121, 121, 121, 121, 121, 120, 120, 120, 120, 119, 119, 119, 119, 118, 118, 118, 117, 117,
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117, 117, 116, 116, 116, 115, 115, 115, 114, 114, 114, 113, 113, 113, 112, 112, 112, 111, 111, 110, 110, 110, 109, 109, 108, 108, 108, 107, 107, 106, 106, 106,
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105, 105, 104, 104, 103, 103, 102, 102, 102, 101, 101, 100, 100, 99, 99, 98, 98, 97, 97, 96, 96, 95, 95, 94, 94, 93, 93, 92, 91, 91, 90, 90,
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89, 89, 88, 88, 87, 87, 86, 85, 85, 84, 84, 83, 82, 82, 81, 81, 80, 79, 79, 78, 78, 77, 76, 76, 75, 75, 74, 73, 73, 72, 71, 71,
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70, 69, 69, 68, 67, 67, 66, 65, 65, 64, 63, 63, 62, 61, 61, 60, 59, 59, 58, 57, 57, 56, 55, 55, 54, 53, 52, 52, 51, 50, 50, 49,
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48, 47, 47, 46, 45, 44, 44, 43, 42, 42, 41, 40, 39, 39, 38, 37, 36, 36, 35, 34, 33, 33, 32, 31, 30, 30, 29, 28, 27, 27, 26, 25,
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24, 24, 23, 22, 21, 20, 20, 19, 18, 17, 17, 16, 15, 14, 13, 13, 12, 11, 10, 10, 9, 8, 7, 7, 6, 5, 4, 3, 3, 2, 1, 0,
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0, 0, -1, -2, -3, -3, -4, -5, -6, -7, -7, -8, -9, -10, -10, -11, -12, -13, -13, -14, -15, -16, -17, -17, -18, -19, -20, -20, -21, -22, -23, -24,
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-24, -25, -26, -27, -27, -28, -29, -30, -30, -31, -32, -33, -33, -34, -35, -36, -36, -37, -38, -39, -39, -40, -41, -42, -42, -43, -44, -44, -45, -46, -47, -47,
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-48, -49, -50, -50, -51, -52, -52, -53, -54, -55, -55, -56, -57, -57, -58, -59, -59, -60, -61, -61, -62, -63, -63, -64, -65, -65, -66, -67, -67, -68, -69, -69,
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-70, -71, -71, -72, -73, -73, -74, -75, -75, -76, -76, -77, -78, -78, -79, -79, -80, -81, -81, -82, -82, -83, -84, -84, -85, -85, -86, -87, -87, -88, -88, -89,
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-89, -90, -90, -91, -91, -92, -93, -93, -94, -94, -95, -95, -96, -96, -97, -97, -98, -98, -99, -99, -100, -100, -101, -101, -102, -102, -102, -103, -103, -104, -104, -105,
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-105, -106, -106, -106, -107, -107, -108, -108, -108, -109, -109, -110, -110, -110, -111, -111, -112, -112, -112, -113, -113, -113, -114, -114, -114, -115, -115, -115, -116, -116, -116, -117,
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-117, -117, -117, -118, -118, -118, -119, -119, -119, -119, -120, -120, -120, -120, -121, -121, -121, -121, -121, -122, -122, -122, -122, -123, -123, -123, -123, -123, -123, -124, -124, -124,
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-124, -124, -124, -124, -125, -125, -125, -125, -125, -125, -125, -125, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126,
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-127, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -126, -125, -125, -125, -125, -125, -125, -125, -125, -124, -124, -124,
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-124, -124, -124, -124, -123, -123, -123, -123, -123, -123, -122, -122, -122, -122, -121, -121, -121, -121, -121, -120, -120, -120, -120, -119, -119, -119, -119, -118, -118, -118, -117, -117,
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-117, -117, -116, -116, -116, -115, -115, -115, -114, -114, -114, -113, -113, -113, -112, -112, -112, -111, -111, -110, -110, -110, -109, -109, -108, -108, -108, -107, -107, -106, -106, -106,
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-105, -105, -104, -104, -103, -103, -102, -102, -102, -101, -101, -100, -100, -99, -99, -98, -98, -97, -97, -96, -96, -95, -95, -94, -94, -93, -93, -92, -91, -91, -90, -90,
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-89, -89, -88, -88, -87, -87, -86, -85, -85, -84, -84, -83, -82, -82, -81, -81, -80, -79, -79, -78, -78, -77, -76, -76, -75, -75, -74, -73, -73, -72, -71, -71,
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-70, -69, -69, -68, -67, -67, -66, -65, -65, -64, -63, -63, -62, -61, -61, -60, -59, -59, -58, -57, -57, -56, -55, -55, -54, -53, -52, -52, -51, -50, -50, -49,
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-48, -47, -47, -46, -45, -44, -44, -43, -42, -42, -41, -40, -39, -39, -38, -37, -36, -36, -35, -34, -33, -33, -32, -31, -30, -30, -29, -28, -27, -27, -26, -25,
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-24, -24, -23, -22, -21, -20, -20, -19, -18, -17, -17, -16, -15, -14, -13, -13, -12, -11, -10, -10, -9, -8, -7, -7, -6, -5, -4, -3, -3, -2, -1, 0
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};
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#else
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#define ACCUMULATOR_BIT_SHIFT (ACCUMULATOR_BITS-8)
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static const int8_t ddsSineTable[256] PROGMEM = {
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0, 3, 6, 9, 12, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49,
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51, 54, 57, 60, 63, 65, 68, 71, 73, 76, 78, 81, 83, 85, 88, 90,
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92, 94, 96, 98, 100, 102, 104, 106, 107, 109, 111, 112, 113, 115,
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116, 117, 118, 120, 121, 122, 122, 123, 124, 125, 125, 126, 126,
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126, 127, 127, 127, 127, 127, 127, 127, 126, 126, 126, 125, 125,
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124, 123, 122, 122, 121, 120, 118, 117, 116, 115, 113, 112, 111,
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109, 107, 106, 104, 102, 100, 98, 96, 94, 92, 90, 88, 85, 83, 81,
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78, 76, 73, 71, 68, 65, 63, 60, 57, 54, 51, 49, 46, 43, 40, 37,
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34, 31, 28, 25, 22, 19, 16, 12, 9, 6, 3, 0, -3, -6, -9, -12, -16,
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-19, -22, -25, -28, -31, -34, -37, -40, -43, -46, -49, -51, -54,
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-57, -60, -63, -65, -68, -71, -73, -76, -78, -81, -83, -85, -88,
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-90, -92, -94, -96, -98, -100, -102, -104, -106, -107, -109, -111,
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-112, -113, -115, -116, -117, -118, -120, -121, -122, -122, -123,
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-124, -125, -125, -126, -126, -126, -127, -127, -127, -127, -127,
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-127, -127, -126, -126, -126, -125, -125, -124, -123, -122, -122,
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-121, -120, -118, -117, -116, -115, -113, -112, -111, -109, -107,
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-106, -104, -102, -100, -98, -96, -94, -92, -90, -88, -85, -83,
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-81, -78, -76, -73, -71, -68, -65, -63, -60, -57, -54, -51, -49,
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-46, -43, -40, -37, -34, -31, -28, -25, -22, -19, -16, -12, -9, -6, -3
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};
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#endif /* DDS_TABLE_LARGE */
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class DDS {
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public:
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DDS(): refclk(DDS_REFCLK_DEFAULT), refclkOffset(DDS_REFCLK_OFFSET),
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accumulator(0), running(false),
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timeLimited(false), tickDuration(0), amplitude(255)
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{};
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// Start all of the timers needed
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void start();
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// Is the DDS presently producing a tone?
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const bool isRunning() { return running; };
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// Stop the DDS timers
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void stop();
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// Start and stop the PWM output
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void on() {
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timeLimited = false;
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running = true;
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}
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// Provide a duration in ms for the tone
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void on(unsigned short duration) {
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// Duration in ticks from milliseconds is:
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// t = (1/refclk)
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tickDuration = (unsigned long)((unsigned long)duration * (unsigned long)refclk) / 1000;
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timeLimited = true;
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running = true;
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}
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void off() {
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running = false;
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}
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// Generate a tone for a specific amount of time
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void play(unsigned short freq, unsigned short duration) {
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setFrequency(freq);
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on(duration);
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}
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// Blocking version
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void playWait(unsigned short freq, unsigned short duration) {
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play(freq, duration);
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delay(duration);
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}
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// Use these to get some calculated values for specific frequencies
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// or to get the current frequency stepping rate.
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ddsAccumulator_t calcFrequency(unsigned short freq);
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ddsAccumulator_t getPhaseAdvance() { return stepRate; };
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// Our maximum clock isn't very high, so our highest
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// frequency supported will fit in a short.
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void setFrequency(unsigned short freq) { stepRate = calcFrequency(freq); };
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void setPrecalcFrequency(ddsAccumulator_t freq) { stepRate = freq; };
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// Handle phase shifts
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void setPhaseDeg(int16_t degrees);
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void changePhaseDeg(int16_t degrees);
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// Adjustable reference clock. This shoud be done before the timers are
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// started, or they will need to be restarted. Frequencies will need to
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// be set again to use the new clock.
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void setReferenceClock(unsigned long ref) {
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refclk = ref;
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}
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unsigned long getReferenceClock() {
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return refclk;
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}
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void setReferenceOffset(int16_t offset) {
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refclkOffset = offset;
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}
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int16_t getReferenceOffset() {
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return refclkOffset;
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}
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uint8_t getDutyCycle();
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// Set a scaling factor. To keep things quick, this is a power of 2 value.
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// Set it with 0 for lowest (which will be off), 8 is highest.
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void setAmplitude(unsigned char amp) {
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amplitude = amp;
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}
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// This is the function called by the ADC_vect ISR to produce the tones
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void clockTick();
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private:
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volatile bool running;
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volatile unsigned long tickDuration;
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volatile bool timeLimited;
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volatile unsigned char amplitude;
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volatile ddsAccumulator_t accumulator;
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volatile ddsAccumulator_t stepRate;
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ddsAccumulator_t refclk;
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int16_t refclkOffset;
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static DDS *sDDS;
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};
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#endif /* _DDS_H_ */
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