From 5dd3c9df928fb46c96fb857aab499beec65ba501 Mon Sep 17 00:00:00 2001 From: nick6x Date: Fri, 26 Aug 2016 11:09:36 -0700 Subject: [PATCH] first commit --- README.md | Bin 0 -> 16 bytes library.properties | 10 ++ src/DDS.cpp | 175 ++++++++++++++++++++++++++++++++++ src/DDS.h | 228 +++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 413 insertions(+) create mode 100644 README.md create mode 100644 library.properties create mode 100644 src/DDS.cpp create mode 100644 src/DDS.h diff --git a/README.md b/README.md new file mode 100644 index 0000000000000000000000000000000000000000..4830f6b15c02c9037b6f97fc339c4dc04f9abb90 GIT binary patch literal 16 VcmezWPnki1!379|8F(4E7yv0w12X^s literal 0 HcmV?d00001 diff --git a/library.properties b/library.properties new file mode 100644 index 0000000..29f8f61 --- /dev/null +++ b/library.properties @@ -0,0 +1,10 @@ +name=DDS +version=1.0.2 +author=Morgan Redfield , Casey Halverson +maintainer=Morgan Redfield +sentence=A library for use with HamShield by Enhanced Radio Devices. +paragraph= +category=Device Control +url=http://www.hamshield.com +architectures=* +includes=DDS.h \ No newline at end of file diff --git a/src/DDS.cpp b/src/DDS.cpp new file mode 100644 index 0000000..8772fc7 --- /dev/null +++ b/src/DDS.cpp @@ -0,0 +1,175 @@ +#include +#include "DDS.h" + +// To start the DDS, we use Timer1, set to the reference clock +// We use Timer2 for the PWM output, running as fast as feasible +void DDS::start() { + // Use the clkIO clock rate + ASSR &= ~(_BV(EXCLK) | _BV(AS2)); + + // First, the timer for the PWM output + // Setup the timer to use OC2B (pin 3) in fast PWM mode with a configurable top + // Run it without the prescaler +#ifdef DDS_PWM_PIN_3 + TCCR2A = (TCCR2A | _BV(COM2B1)) & ~(_BV(COM2B0) | _BV(COM2A1) | _BV(COM2A0)) | + _BV(WGM21) | _BV(WGM20); + TCCR2B = (TCCR2B & ~(_BV(CS22) | _BV(CS21))) | _BV(CS20) | _BV(WGM22); +#else + // Alternatively, use pin 11 + // Enable output compare on OC2A, toggle mode + TCCR2A = _BV(COM2A1) | _BV(WGM21) | _BV(WGM20); + //TCCR2A = (TCCR2A | _BV(COM2A1)) & ~(_BV(COM2A0) | _BV(COM2B1) | _BV(COM2B0)) | + // _BV(WGM21) | _BV(WGM20); + TCCR2B = _BV(CS20); +#endif + + // Set the top limit, which will be our duty cycle accuracy. + // Setting Comparator Bits smaller will allow for higher frequency PWM, + // with the loss of resolution. +#ifdef DDS_PWM_PIN_3 + OCR2A = pow(2,COMPARATOR_BITS)-1; + OCR2B = 0; +#else + OCR2A = 0; +#endif + +#ifdef DDS_USE_ONLY_TIMER2 + TIMSK2 |= _BV(TOIE2); +#endif + + // Second, setup Timer1 to trigger the ADC interrupt + // This lets us use decoding functions that run at the same reference + // clock as the DDS. + // We use ICR1 as TOP and prescale by 8 + TCCR1B = _BV(CS10) | _BV(WGM13) | _BV(WGM12); + TCCR1A = 0; + ICR1 = ((F_CPU / 1) / refclk) - 1; +#ifdef DDS_DEBUG_SERIAL + Serial.print(F("DDS SysClk: ")); + Serial.println(F_CPU/8); + Serial.print(F("DDS RefClk: ")); + Serial.println(refclk, DEC); + Serial.print(F("DDS ICR1: ")); + Serial.println(ICR1, DEC); +#endif + + // Configure the ADC here to automatically run and be triggered off Timer1 + ADMUX = _BV(REFS0) | _BV(ADLAR) | 0; // Channel 0, shift result left (ADCH used) + DDRC &= ~_BV(0); + PORTC &= ~_BV(0); + DIDR0 |= _BV(0); + ADCSRB = _BV(ADTS2) | _BV(ADTS1) | _BV(ADTS0); + ADCSRA = _BV(ADEN) | _BV(ADSC) | _BV(ADATE) | _BV(ADIE) | _BV(ADPS2); // | _BV(ADPS0); +} + +void DDS::stop() { + // TODO: Stop the timers. +#ifndef DDS_USE_ONLY_TIMER2 + TCCR1B = 0; +#endif + TCCR2B = 0; +} + +// Set our current sine wave frequency in Hz +ddsAccumulator_t DDS::calcFrequency(unsigned short freq) { + // Fo = (M*Fc)/2^N + // M = (Fo/Fc)*2^N + ddsAccumulator_t newStep; + if(refclk == DDS_REFCLK_DEFAULT) { + // Try to use precalculated values if possible + if(freq == 2200) { + newStep = (2200.0 / (DDS_REFCLK_DEFAULT+DDS_REFCLK_OFFSET)) * pow(2,ACCUMULATOR_BITS); + } else if (freq == 1200) { + newStep = (1200.0 / (DDS_REFCLK_DEFAULT+DDS_REFCLK_OFFSET)) * pow(2,ACCUMULATOR_BITS); + } else if(freq == 2400) { + newStep = (2400.0 / (DDS_REFCLK_DEFAULT+DDS_REFCLK_OFFSET)) * pow(2,ACCUMULATOR_BITS); + } else if (freq == 1500) { + newStep = (1500.0 / (DDS_REFCLK_DEFAULT+DDS_REFCLK_OFFSET)) * pow(2,ACCUMULATOR_BITS); + } else if (freq == 600) { + newStep = (600.0 / (DDS_REFCLK_DEFAULT+DDS_REFCLK_OFFSET)) * pow(2,ACCUMULATOR_BITS); + } + } else { + newStep = pow(2,ACCUMULATOR_BITS)*freq / (refclk+refclkOffset); + } + return newStep; +} + +// Degrees should be between -360 and +360 (others don't make much sense) +void DDS::setPhaseDeg(int16_t degrees) { + accumulator = degrees * (pow(2,ACCUMULATOR_BITS)/360.0); +} +void DDS::changePhaseDeg(int16_t degrees) { + accumulator += degrees * (pow(2,ACCUMULATOR_BITS)/360.0); +} + +// TODO: Clean this up a bit.. +void DDS::clockTick() { +/* if(running) { + accumulator += stepRate; + OCR2A = getDutyCycle(); + } + return;*/ + if(running) { + accumulator += stepRate; + if(timeLimited && tickDuration == 0) { +#ifndef DDS_PWM_PIN_3 + OCR2A = 0; +#else +#ifdef DDS_IDLE_HIGH + // Set the duty cycle to 50% + OCR2B = pow(2,COMPARATOR_BITS)/2; +#else + // Set duty cycle to 0, effectively off + OCR2B = 0; +#endif +#endif + running = false; + accumulator = 0; + } else { +#ifdef DDS_PWM_PIN_3 + OCR2B = getDutyCycle(); +#else + OCR2A = getDutyCycle(); +#endif + } + // Reduce our playback duration by one tick + tickDuration--; + } else { + // Hold it low +#ifndef DDS_PWM_PIN_3 + OCR2A = 0; +#else +#ifdef DDS_IDLE_HIGH + // Set the duty cycle to 50% + OCR2B = pow(2,COMPARATOR_BITS)/2; +#else + // Set duty cycle to 0, effectively off + OCR2B = 0; +#endif +#endif + } +} + +uint8_t DDS::getDutyCycle() { + #if ACCUMULATOR_BIT_SHIFT >= 24 + uint16_t phAng; + #else + uint8_t phAng; + #endif + if(amplitude == 0) // Shortcut out on no amplitude + return 128>>(8-COMPARATOR_BITS); + phAng = (accumulator >> ACCUMULATOR_BIT_SHIFT); + int8_t position = pgm_read_byte_near(ddsSineTable + phAng); //>>(8-COMPARATOR_BITS); + // Apply scaling and return + int16_t scaled = position; + // output = ((duty * amplitude) / 256) + 128 + // This keeps amplitudes centered around 50% duty + if(amplitude != 255) { // Amplitude is reduced, so do the full math + scaled *= amplitude; + scaled >>= 8+(8-COMPARATOR_BITS); + } else { // Otherwise, only shift for the comparator bits + scaled >>= (8-COMPARATOR_BITS); + } + scaled += 128>>(8-COMPARATOR_BITS); + return scaled; +} diff --git a/src/DDS.h b/src/DDS.h new file mode 100644 index 0000000..57cf40b --- /dev/null +++ b/src/DDS.h @@ -0,0 +1,228 @@ +#ifndef _DDS_H_ +#define _DDS_H_ + +#include + +// 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 uint16_t ddsAccumulator_t; +#else +#define ACCUMULATOR_BITS 32 +typedef uint32_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 9600 +#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 + +// Output some of the calculations and information about the DDS over serial +//#define DDS_DEBUG_SERIAL + +// 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 int8_t ddsSineTable[1024] PROGMEM = { + 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, + 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, + 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, + 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, + 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, + 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, + 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, + 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, + 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, + 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, + 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, + 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, + 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, + 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, + 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, + 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, + 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, + -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, + -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, + -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, + -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, + -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, + -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, + -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, + -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, + -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, + -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, + -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, + -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, + -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, + -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, + -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 +}; +#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 + }; +#endif /* DDS_TABLE_LARGE */ + +class DDS { +public: + DDS(): refclk(DDS_REFCLK_DEFAULT), refclkOffset(DDS_REFCLK_OFFSET), + 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; + } + + void setReferenceOffset(int16_t offset) { + refclkOffset = offset; + } + int16_t getReferenceOffset() { + return refclkOffset; + } + + 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; + int16_t refclkOffset; + static DDS *sDDS; +}; + +#endif /* _DDS_H_ */