267 lines
11 KiB
C++
267 lines
11 KiB
C++
#ifndef _DDS_H_
|
|
#define _DDS_H_
|
|
|
|
#include <avr/pgmspace.h>
|
|
|
|
// Use pin 3 for PWM? If not defined, use pin 11
|
|
// Quality on pin 3 is higher than on 11, as it can be clocked faster
|
|
// when the COMPARATOR_BITS value is less than 8
|
|
#define DDS_PWM_PIN_3
|
|
|
|
// Normally, we turn on timer2 and timer1, and have ADC sampling as our clock
|
|
// Define this to only use Timer2, and not start the ADC clock
|
|
// #define DDS_USE_ONLY_TIMER2
|
|
|
|
// Use a short (16 bit) accumulator. Phase accuracy is reduced, but speed
|
|
// is increased, along with a reduction in memory use.
|
|
#define SHORT_ACCUMULATOR
|
|
|
|
#ifdef SHORT_ACCUMULATOR
|
|
#define ACCUMULATOR_BITS 16
|
|
typedef int16_t ddsAccumulator_t;
|
|
#else
|
|
#define ACCUMULATOR_BITS 32
|
|
typedef int32_t ddsAccumulator_t;
|
|
#endif
|
|
|
|
// If defined, the timer will idle at 50% duty cycle
|
|
// This leaves it floating in the centre of the PWM/DAC voltage range
|
|
#define DDS_IDLE_HIGH
|
|
|
|
// Select how fast the PWM is, at the expense of level accuracy.
|
|
// A faster PWM rate will make for easier filtering of the output wave,
|
|
// while a slower one will allow for more accurate voltage level outputs,
|
|
// but will increase the filtering requirements on the output.
|
|
// 8 = 62.5kHz PWM
|
|
// 7 = 125kHz PWM
|
|
// 6 = 250kHz PWM
|
|
#ifdef DDS_PWM_PIN_3
|
|
#define COMPARATOR_BITS 6
|
|
#else // When using pin 11, we always want 8 bits
|
|
#define COMPARATOR_BITS 8
|
|
#endif
|
|
|
|
// This is how often we'll perform a phase advance, as well as ADC sampling
|
|
// rate. The higher this value, the smoother the output wave will be, at the
|
|
// expense of CPU time. It maxes out around 62000 (TBD)
|
|
// May be overridden in the sketch to improve performance
|
|
#ifndef DDS_REFCLK_DEFAULT
|
|
#define DDS_REFCLK_DEFAULT 38400
|
|
#endif
|
|
// As each Arduino crystal is a little different, this can be fine tuned to
|
|
// provide more accurate frequencies. Adjustments in the range of hundreds
|
|
// is a good start.
|
|
#ifndef DDS_REFCLK_OFFSET
|
|
#define DDS_REFCLK_OFFSET 0
|
|
#endif
|
|
|
|
#ifdef DDS_USE_ONLY_TIMER2
|
|
// TODO: Figure out where this clock value is generated from
|
|
#define DDS_REFCLK_DEFAULT (62500/4)
|
|
#endif
|
|
|
|
// When defined, use the 1024 element sine lookup table. This improves phase
|
|
// accuracy, at the cost of more flash and CPU requirements.
|
|
// #define DDS_TABLE_LARGE
|
|
|
|
#ifdef DDS_TABLE_LARGE
|
|
// How many bits to keep from the accumulator to look up in this table
|
|
#define ACCUMULATOR_BIT_SHIFT (ACCUMULATOR_BITS-10)
|
|
static const uint8_t ddsSineTable[1024] PROGMEM = {
|
|
128,128,129,130,131,131,132,133,134,135,135,136,137,138,138,139,
|
|
140,141,142,142,143,144,145,145,146,147,148,149,149,150,151,152,
|
|
152,153,154,155,155,156,157,158,158,159,160,161,162,162,163,164,
|
|
165,165,166,167,167,168,169,170,170,171,172,173,173,174,175,176,
|
|
176,177,178,178,179,180,181,181,182,183,183,184,185,186,186,187,
|
|
188,188,189,190,190,191,192,192,193,194,194,195,196,196,197,198,
|
|
198,199,200,200,201,202,202,203,203,204,205,205,206,207,207,208,
|
|
208,209,210,210,211,211,212,213,213,214,214,215,215,216,217,217,
|
|
218,218,219,219,220,220,221,221,222,222,223,224,224,225,225,226,
|
|
226,227,227,228,228,228,229,229,230,230,231,231,232,232,233,233,
|
|
234,234,234,235,235,236,236,236,237,237,238,238,238,239,239,240,
|
|
240,240,241,241,241,242,242,242,243,243,243,244,244,244,245,245,
|
|
245,246,246,246,246,247,247,247,248,248,248,248,249,249,249,249,
|
|
250,250,250,250,250,251,251,251,251,251,252,252,252,252,252,252,
|
|
253,253,253,253,253,253,253,254,254,254,254,254,254,254,254,254,
|
|
254,254,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
|
|
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,254,
|
|
254,254,254,254,254,254,254,254,254,254,253,253,253,253,253,253,
|
|
253,252,252,252,252,252,252,251,251,251,251,251,250,250,250,250,
|
|
250,249,249,249,249,248,248,248,248,247,247,247,246,246,246,246,
|
|
245,245,245,244,244,244,243,243,243,242,242,242,241,241,241,240,
|
|
240,240,239,239,238,238,238,237,237,236,236,236,235,235,234,234,
|
|
234,233,233,232,232,231,231,230,230,229,229,228,228,228,227,227,
|
|
226,226,225,225,224,224,223,222,222,221,221,220,220,219,219,218,
|
|
218,217,217,216,215,215,214,214,213,213,212,211,211,210,210,209,
|
|
208,208,207,207,206,205,205,204,203,203,202,202,201,200,200,199,
|
|
198,198,197,196,196,195,194,194,193,192,192,191,190,190,189,188,
|
|
188,187,186,186,185,184,183,183,182,181,181,180,179,178,178,177,
|
|
176,176,175,174,173,173,172,171,170,170,169,168,167,167,166,165,
|
|
165,164,163,162,162,161,160,159,158,158,157,156,155,155,154,153,
|
|
152,152,151,150,149,149,148,147,146,145,145,144,143,142,142,141,
|
|
140,139,138,138,137,136,135,135,134,133,132,131,131,130,129,128,
|
|
128,127,126,125,124,124,123,122,121,120,120,119,118,117,117,116,
|
|
115,114,113,113,112,111,110,110,109,108,107,106,106,105,104,103,
|
|
103,102,101,100,100,99,98,97,97,96,95,94,93,93,92,91,
|
|
90,90,89,88,88,87,86,85,85,84,83,82,82,81,80,79,
|
|
79,78,77,77,76,75,74,74,73,72,72,71,70,69,69,68,
|
|
67,67,66,65,65,64,63,63,62,61,61,60,59,59,58,57,
|
|
57,56,55,55,54,53,53,52,52,51,50,50,49,48,48,47,
|
|
47,46,45,45,44,44,43,42,42,41,41,40,40,39,38,38,
|
|
37,37,36,36,35,35,34,34,33,33,32,31,31,30,30,29,
|
|
29,28,28,27,27,27,26,26,25,25,24,24,23,23,22,22,
|
|
21,21,21,20,20,19,19,19,18,18,17,17,17,16,16,15,
|
|
15,15,14,14,14,13,13,13,12,12,12,11,11,11,10,10,
|
|
10,9,9,9,9,8,8,8,7,7,7,7,6,6,6,6,
|
|
5,5,5,5,5,4,4,4,4,4,3,3,3,3,3,3,
|
|
2,2,2,2,2,2,2,1,1,1,1,1,1,1,1,1,
|
|
1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
|
|
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,
|
|
1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,
|
|
2,3,3,3,3,3,3,4,4,4,4,4,5,5,5,5,
|
|
5,6,6,6,6,7,7,7,7,8,8,8,9,9,9,9,
|
|
10,10,10,11,11,11,12,12,12,13,13,13,14,14,14,15,
|
|
15,15,16,16,17,17,17,18,18,19,19,19,20,20,21,21,
|
|
21,22,22,23,23,24,24,25,25,26,26,27,27,27,28,28,
|
|
29,29,30,30,31,31,32,33,33,34,34,35,35,36,36,37,
|
|
37,38,38,39,40,40,41,41,42,42,43,44,44,45,45,46,
|
|
47,47,48,48,49,50,50,51,52,52,53,53,54,55,55,56,
|
|
57,57,58,59,59,60,61,61,62,63,63,64,65,65,66,67,
|
|
67,68,69,69,70,71,72,72,73,74,74,75,76,77,77,78,
|
|
79,79,80,81,82,82,83,84,85,85,86,87,88,88,89,90,
|
|
90,91,92,93,93,94,95,96,97,97,98,99,100,100,101,102,
|
|
103,103,104,105,106,106,107,108,109,110,110,111,112,113,113,114,
|
|
115,116,117,117,118,119,120,120,121,122,123,124,124,125,126,127
|
|
};
|
|
#else
|
|
#define ACCUMULATOR_BIT_SHIFT (ACCUMULATOR_BITS-8)
|
|
static const int8_t ddsSineTable[256] PROGMEM = {
|
|
0, 3, 6, 9, 12, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49,
|
|
51, 54, 57, 60, 63, 65, 68, 71, 73, 76, 78, 81, 83, 85, 88, 90,
|
|
92, 94, 96, 98, 100, 102, 104, 106, 107, 109, 111, 112, 113, 115,
|
|
116, 117, 118, 120, 121, 122, 122, 123, 124, 125, 125, 126, 126,
|
|
126, 127, 127, 127, 127, 127, 127, 127, 126, 126, 126, 125, 125,
|
|
124, 123, 122, 122, 121, 120, 118, 117, 116, 115, 113, 112, 111,
|
|
109, 107, 106, 104, 102, 100, 98, 96, 94, 92, 90, 88, 85, 83, 81,
|
|
78, 76, 73, 71, 68, 65, 63, 60, 57, 54, 51, 49, 46, 43, 40, 37,
|
|
34, 31, 28, 25, 22, 19, 16, 12, 9, 6, 3, 0, -3, -6, -9, -12, -16,
|
|
-19, -22, -25, -28, -31, -34, -37, -40, -43, -46, -49, -51, -54,
|
|
-57, -60, -63, -65, -68, -71, -73, -76, -78, -81, -83, -85, -88,
|
|
-90, -92, -94, -96, -98, -100, -102, -104, -106, -107, -109, -111,
|
|
-112, -113, -115, -116, -117, -118, -120, -121, -122, -122, -123,
|
|
-124, -125, -125, -126, -126, -126, -127, -127, -127, -127, -127,
|
|
-127, -127, -126, -126, -126, -125, -125, -124, -123, -122, -122,
|
|
-121, -120, -118, -117, -116, -115, -113, -112, -111, -109, -107,
|
|
-106, -104, -102, -100, -98, -96, -94, -92, -90, -88, -85, -83,
|
|
-81, -78, -76, -73, -71, -68, -65, -63, -60, -57, -54, -51, -49,
|
|
-46, -43, -40, -37, -34, -31, -28, -25, -22, -19, -16, -12, -9, -6, -3
|
|
};
|
|
/*static const uint8_t ddsSineTable[256] PROGMEM = {
|
|
128,131,134,137,140,143,146,149,152,155,158,162,165,167,170,173,
|
|
176,179,182,185,188,190,193,196,198,201,203,206,208,211,213,215,
|
|
218,220,222,224,226,228,230,232,234,235,237,238,240,241,243,244,
|
|
245,246,248,249,250,250,251,252,253,253,254,254,254,255,255,255,
|
|
255,255,255,255,254,254,254,253,253,252,251,250,250,249,248,246,
|
|
245,244,243,241,240,238,237,235,234,232,230,228,226,224,222,220,
|
|
218,215,213,211,208,206,203,201,198,196,193,190,188,185,182,179,
|
|
176,173,170,167,165,162,158,155,152,149,146,143,140,137,134,131,
|
|
128,124,121,118,115,112,109,106,103,100,97,93,90,88,85,82,
|
|
79,76,73,70,67,65,62,59,57,54,52,49,47,44,42,40,
|
|
37,35,33,31,29,27,25,23,21,20,18,17,15,14,12,11,
|
|
10,9,7,6,5,5,4,3,2,2,1,1,1,0,0,0,
|
|
0,0,0,0,1,1,1,2,2,3,4,5,5,6,7,9,
|
|
10,11,12,14,15,17,18,20,21,23,25,27,29,31,33,35,
|
|
37,40,42,44,47,49,52,54,57,59,62,65,67,70,73,76,
|
|
79,82,85,88,90,93,97,100,103,106,109,112,115,118,121,124
|
|
};*/
|
|
#endif /* DDS_TABLE_LARGE */
|
|
|
|
class DDS {
|
|
public:
|
|
DDS(): refclk(DDS_REFCLK_DEFAULT), accumulator(0), running(false),
|
|
timeLimited(false), tickDuration(0), amplitude(255)
|
|
{};
|
|
|
|
// Start all of the timers needed
|
|
void start();
|
|
// Is the DDS presently producing a tone?
|
|
const bool isRunning() { return running; };
|
|
// Stop the DDS timers
|
|
void stop();
|
|
|
|
// Start and stop the PWM output
|
|
void on() {
|
|
timeLimited = false;
|
|
running = true;
|
|
}
|
|
// Provide a duration in ms for the tone
|
|
void on(unsigned short duration) {
|
|
// Duration in ticks from milliseconds is:
|
|
// t = (1/refclk)
|
|
tickDuration = (unsigned long)((unsigned long)duration * (unsigned long)refclk) / 1000;
|
|
timeLimited = true;
|
|
running = true;
|
|
}
|
|
void off() {
|
|
running = false;
|
|
}
|
|
|
|
// Generate a tone for a specific amount of time
|
|
void play(unsigned short freq, unsigned short duration) {
|
|
setFrequency(freq);
|
|
on(duration);
|
|
}
|
|
// Blocking version
|
|
void playWait(unsigned short freq, unsigned short duration) {
|
|
play(freq, duration);
|
|
delay(duration);
|
|
}
|
|
|
|
// Use these to get some calculated values for specific frequencies
|
|
// or to get the current frequency stepping rate.
|
|
ddsAccumulator_t calcFrequency(unsigned short freq);
|
|
ddsAccumulator_t getPhaseAdvance() { return stepRate; };
|
|
|
|
// Our maximum clock isn't very high, so our highest
|
|
// frequency supported will fit in a short.
|
|
void setFrequency(unsigned short freq) { stepRate = calcFrequency(freq); };
|
|
void setPrecalcFrequency(ddsAccumulator_t freq) { stepRate = freq; };
|
|
|
|
// Handle phase shifts
|
|
void setPhaseDeg(int16_t degrees);
|
|
void changePhaseDeg(int16_t degrees);
|
|
|
|
// Adjustable reference clock. This shoud be done before the timers are
|
|
// started, or they will need to be restarted. Frequencies will need to
|
|
// be set again to use the new clock.
|
|
void setReferenceClock(unsigned long ref) {
|
|
refclk = ref;
|
|
}
|
|
unsigned long getReferenceClock() {
|
|
return refclk;
|
|
}
|
|
|
|
uint8_t getDutyCycle();
|
|
|
|
// Set a scaling factor. To keep things quick, this is a power of 2 value.
|
|
// Set it with 0 for lowest (which will be off), 8 is highest.
|
|
void setAmplitude(unsigned char amp) {
|
|
amplitude = amp;
|
|
}
|
|
|
|
// This is the function called by the ADC_vect ISR to produce the tones
|
|
void clockTick();
|
|
|
|
private:
|
|
volatile bool running;
|
|
volatile unsigned long tickDuration;
|
|
volatile bool timeLimited;
|
|
volatile unsigned char amplitude;
|
|
volatile ddsAccumulator_t accumulator;
|
|
volatile ddsAccumulator_t stepRate;
|
|
ddsAccumulator_t refclk;
|
|
static DDS *sDDS;
|
|
};
|
|
|
|
#endif /* _DDS_H_ */
|