279 lines
11 KiB
C++
279 lines
11 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 38400
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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 uint8_t ddsSineTable[1024] PROGMEM = {
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128,128,129,130,131,131,132,133,134,135,135,136,137,138,138,139,
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140,141,142,142,143,144,145,145,146,147,148,149,149,150,151,152,
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152,153,154,155,155,156,157,158,158,159,160,161,162,162,163,164,
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165,165,166,167,167,168,169,170,170,171,172,173,173,174,175,176,
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176,177,178,178,179,180,181,181,182,183,183,184,185,186,186,187,
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188,188,189,190,190,191,192,192,193,194,194,195,196,196,197,198,
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198,199,200,200,201,202,202,203,203,204,205,205,206,207,207,208,
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208,209,210,210,211,211,212,213,213,214,214,215,215,216,217,217,
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218,218,219,219,220,220,221,221,222,222,223,224,224,225,225,226,
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226,227,227,228,228,228,229,229,230,230,231,231,232,232,233,233,
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234,234,234,235,235,236,236,236,237,237,238,238,238,239,239,240,
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240,240,241,241,241,242,242,242,243,243,243,244,244,244,245,245,
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245,246,246,246,246,247,247,247,248,248,248,248,249,249,249,249,
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250,250,250,250,250,251,251,251,251,251,252,252,252,252,252,252,
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253,253,253,253,253,253,253,254,254,254,254,254,254,254,254,254,
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254,254,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
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255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,254,
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254,254,254,254,254,254,254,254,254,254,253,253,253,253,253,253,
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253,252,252,252,252,252,252,251,251,251,251,251,250,250,250,250,
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250,249,249,249,249,248,248,248,248,247,247,247,246,246,246,246,
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245,245,245,244,244,244,243,243,243,242,242,242,241,241,241,240,
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240,240,239,239,238,238,238,237,237,236,236,236,235,235,234,234,
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234,233,233,232,232,231,231,230,230,229,229,228,228,228,227,227,
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226,226,225,225,224,224,223,222,222,221,221,220,220,219,219,218,
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218,217,217,216,215,215,214,214,213,213,212,211,211,210,210,209,
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208,208,207,207,206,205,205,204,203,203,202,202,201,200,200,199,
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198,198,197,196,196,195,194,194,193,192,192,191,190,190,189,188,
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188,187,186,186,185,184,183,183,182,181,181,180,179,178,178,177,
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176,176,175,174,173,173,172,171,170,170,169,168,167,167,166,165,
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165,164,163,162,162,161,160,159,158,158,157,156,155,155,154,153,
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152,152,151,150,149,149,148,147,146,145,145,144,143,142,142,141,
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140,139,138,138,137,136,135,135,134,133,132,131,131,130,129,128,
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128,127,126,125,124,124,123,122,121,120,120,119,118,117,117,116,
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115,114,113,113,112,111,110,110,109,108,107,106,106,105,104,103,
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103,102,101,100,100,99,98,97,97,96,95,94,93,93,92,91,
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90,90,89,88,88,87,86,85,85,84,83,82,82,81,80,79,
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79,78,77,77,76,75,74,74,73,72,72,71,70,69,69,68,
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67,67,66,65,65,64,63,63,62,61,61,60,59,59,58,57,
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57,56,55,55,54,53,53,52,52,51,50,50,49,48,48,47,
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47,46,45,45,44,44,43,42,42,41,41,40,40,39,38,38,
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37,37,36,36,35,35,34,34,33,33,32,31,31,30,30,29,
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29,28,28,27,27,27,26,26,25,25,24,24,23,23,22,22,
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21,21,21,20,20,19,19,19,18,18,17,17,17,16,16,15,
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15,15,14,14,14,13,13,13,12,12,12,11,11,11,10,10,
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10,9,9,9,9,8,8,8,7,7,7,7,6,6,6,6,
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5,5,5,5,5,4,4,4,4,4,3,3,3,3,3,3,
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2,2,2,2,2,2,2,1,1,1,1,1,1,1,1,1,
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1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,
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1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,
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2,3,3,3,3,3,3,4,4,4,4,4,5,5,5,5,
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5,6,6,6,6,7,7,7,7,8,8,8,9,9,9,9,
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10,10,10,11,11,11,12,12,12,13,13,13,14,14,14,15,
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15,15,16,16,17,17,17,18,18,19,19,19,20,20,21,21,
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21,22,22,23,23,24,24,25,25,26,26,27,27,27,28,28,
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29,29,30,30,31,31,32,33,33,34,34,35,35,36,36,37,
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37,38,38,39,40,40,41,41,42,42,43,44,44,45,45,46,
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47,47,48,48,49,50,50,51,52,52,53,53,54,55,55,56,
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57,57,58,59,59,60,61,61,62,63,63,64,65,65,66,67,
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67,68,69,69,70,71,72,72,73,74,74,75,76,77,77,78,
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79,79,80,81,82,82,83,84,85,85,86,87,88,88,89,90,
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90,91,92,93,93,94,95,96,97,97,98,99,100,100,101,102,
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103,103,104,105,106,106,107,108,109,110,110,111,112,113,113,114,
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115,116,117,117,118,119,120,120,121,122,123,124,124,125,126,127
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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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/*static const uint8_t ddsSineTable[256] PROGMEM = {
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128,131,134,137,140,143,146,149,152,155,158,162,165,167,170,173,
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176,179,182,185,188,190,193,196,198,201,203,206,208,211,213,215,
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218,220,222,224,226,228,230,232,234,235,237,238,240,241,243,244,
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245,246,248,249,250,250,251,252,253,253,254,254,254,255,255,255,
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255,255,255,255,254,254,254,253,253,252,251,250,250,249,248,246,
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245,244,243,241,240,238,237,235,234,232,230,228,226,224,222,220,
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218,215,213,211,208,206,203,201,198,196,193,190,188,185,182,179,
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176,173,170,167,165,162,158,155,152,149,146,143,140,137,134,131,
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128,124,121,118,115,112,109,106,103,100,97,93,90,88,85,82,
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79,76,73,70,67,65,62,59,57,54,52,49,47,44,42,40,
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37,35,33,31,29,27,25,23,21,20,18,17,15,14,12,11,
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10,9,7,6,5,5,4,3,2,2,1,1,1,0,0,0,
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0,0,0,0,1,1,1,2,2,3,4,5,5,6,7,9,
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10,11,12,14,15,17,18,20,21,23,25,27,29,31,33,35,
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37,40,42,44,47,49,52,54,57,59,62,65,67,70,73,76,
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79,82,85,88,90,93,97,100,103,106,109,112,115,118,121,124
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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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