AD9833 Portable Function Generator

#ifndef AD9833_H
#define AD9833_H

#include <SPI.h>
//#include "LiquidCrystal_I2C.h"

class AD9833
{
  public:
    //Initialise the AD9833
    //_FYNC is the pin on the uC where FYNC is connected
    //_mclk is the frequency of the crystal generator 
    AD9833(int _FSYNC, unsigned long _mclk);
    //Set and get for frequency
    void setFreq(unsigned long _freq);
    unsigned long getFreq();
    //Set and get for phase
    void setPhase(int _phase);
    int getPhase();
    //Set and get for control register
    void setCtrlReg(unsigned long _controlRegister);
    int getCtrlReg();
    //Send data to AD9833
    void writeData(int data);
    //Send the control register
    void writeCtrlReg();
    //Update the control register with appopiate values for sleep/reset/mode
    //s = 0 No power down
    //s = 1 DAC powered down
    //s = 2 Internal clock powered down
    //s = 3 Both DAC and internal clock powered down
    void sleep(int s);
    //r = 0 Disable Reset
    //r = 1 Enable Reset
    void reset(int r);
    //m = 0 Sine
    //m = 1 Triangle
    //m = 2 Clock (rectangle)
    void mode(int m);
    //r = 0 FREQ0 and PHASE0 are used
    //r = 1 FREQ1 and PHASE1 are used
    void setFPRegister(int r);
    //void lcdDebugInit(LiquidCrystal_I2C *);
    //void lcdDebug(String);

  private:
    int FSYNC;          //FSYNC Pin of AD9833 has to be connected to a GPIO pin
    unsigned long freq; //Output frequency
    int phase;          //Signal phase shift
    unsigned long mclk; //External oscillator frequency
    int fqRegister;    //Switch between Frequency and Phase register 1/0
    int pRegister;
    int controlRegister;
    //LiquidCrystal_I2C *debugger; //Debugging stuff through I2C
    //boolean debugging;
};

#endif

#include <SPI.h>
#include "AD9833.h"

AD9833::AD9833(int _FSYNC, unsigned long _mclk) {
  FSYNC = _FSYNC;
  pinMode(FSYNC, OUTPUT);     // Set FSYNC pin as input
  mclk = _mclk;               // Set the oscillator used, for example 24MHz
  controlRegister = 0x2000;   // Default control register : FREQ0, PHASE0, Sine
  fqRegister = 0x4000;        // Default frequency register is 0
  pRegister = 0xC000;         // Default phase register is 0
  SPI.begin();                // Initialise the SPI BUS
  SPI.setDataMode(SPI_MODE2); // Set SPI in mode2, this should be moved in
  // methods when SPI.transfer is called in case you
  // have multiple devices using the SPI bus
}

void AD9833::writeData(int data) {
  // FSYNC pin must be pulled low when new data is received by AD9833
  digitalWrite(FSYNC, LOW);
  // Send the first 8 MSBs of data
  SPI.transfer(highByte(data));
  // Send the last 8 LSBs of data
  SPI.transfer(lowByte(data));
  // Set the FSYNC pin to high then end SPI transaction
  digitalWrite(FSYNC, HIGH);
  // debugging
/*  
  if (debugging) {
    lcdDebug(String(data, HEX));
  }
*/
}

void AD9833::setFreq(unsigned long _freq) {
  // First check that the data received is fine
  unsigned long freqReg;
  // Frequency cannot be negative
  if (_freq < 0) {
    freqReg = 0;
    freq = 0;
  }
  // If the frequency is more than maximum frequency, just set it to maximum
  else if (_freq > mclk) {
    freqReg = pow(2, 28) - 1;
    freq = mclk / 2;
  }
  // If all is good, compute the freqReg knowhing that the analog output is
  // (mclk/2^28) * freqReg
  else {
    freq = _freq;
    freqReg = (freq * pow(2, 28)) / mclk;
  }
  // Initialise two variables that are 16bit long which we use to divide the
  // freqReg in two words
  // set D15 to 0 and D14 to 1 to put data in FREQ0/1 register
  int MSW = ((int)(freqReg >> 14)) | fqRegister; // Take out the first 14bits
  // and set D15 to 0 and D14 to
  // 1 or viceversa depending on
  // FREQ reg
  int LSW = ((int)(freqReg & 0x3FFF)) |
            fqRegister; // Take only the last 14bits using a mask and set D15 to
  // 0 and D14 to 1 or viceversa depending on FREQ reg
  // Send the data, most significant word first
  writeData(LSW);
  writeData(MSW);
}
unsigned long AD9833::getFreq() {
  return freq;
}
void AD9833::setPhase(int _phase) {
  // Phase cannot be negative
  if (_phase < 0) {
    phase = 0;
  }
  // Phase maximum is 2^12
  else if (_phase >= 4096) {
    phase = 4096 - 1;
  }
  // If all is good, set the new phase value
  else {
    phase = _phase;
  }
  // Extract the 12 bits from the freqReg and set D15-1, D14-1, D13-0, D12-X to
  // put data in PHASE0/1 register
  int phaseData = phase | pRegister;
  int LSW = (phase & 0x3FFF) | pRegister;
  writeData(phaseData);
}
int AD9833::getPhase() {
  return phase;
}

void AD9833::setCtrlReg(unsigned long _controlRegister) {
  // Just make sure that the first two bits are set to 0
  controlRegister = _controlRegister & 0x3FFF;
  writeCtrlReg();
}

int AD9833::getCtrlReg() {
  return controlRegister;
}

void AD9833::writeCtrlReg() {
  writeData(controlRegister);
}

void AD9833::sleep(int s) {
  switch (s) {

    case 0: {
        controlRegister &= 0xFF3F; // No power-down: D7-0 and D6-0
      } break;

    case 1: {
        controlRegister &= 0xFF7F; // DAC powered down: D7-0 and D6-1
        controlRegister |= 0x0040;
      } break;

    case 2: {
        controlRegister &= 0xFFBF; // Internal clock disabled: D7-1 and D6-0
        controlRegister |= 0x0080;
      } break;

    case 3: {
        controlRegister |=
          0x00C0; // Both DAC powered down and internal clock disabled
      } break;
  }
  // Update the control register
  writeCtrlReg();
}

void AD9833::reset(int r) {
  if (r == 0) {
    controlRegister &= 0xFEFF; // Set D8 to 0
  }

  else if (r == 1) {
    controlRegister |= 0x0100; // Set D8 to 1
  }
  writeCtrlReg();
}

void AD9833::mode(int m) {
  switch (m) {
    case 0: {
        controlRegister &= 0xFFDD; // Output sine: D5-0 and D1-0
      } break;
    case 1: {
        controlRegister &= 0xFFDF; // Output triangle: D5-0 and D1-1
        controlRegister |= 0x0002;
      } break;
    case 2: {
        controlRegister &= 0xFFFD; // Output clock (rectangle): D5-1 and D1-0
        controlRegister |= 0x0020;
      } break;
  }
  writeCtrlReg();
}

void AD9833::setFPRegister(int r) {
  if (r == 0) {
    controlRegister &= 0xF3FF; // Set D11 and D10 in control register to 0
    fqRegister = 0x4000; // Set D15 to 0 and D14 to 1 in a variable that will
    // later choose the FREQ0 register
    pRegister =
      0xC000; // Set D15 to 1 and D14 to 1 and D13 to 0 for the PHASE register
  } else if (r == 1) {
    controlRegister |= 0x0C00; // Set D11 and D10 in control register to 1
    fqRegister = 0x8000; // Set D15 to 1 and D14 to 0 in a variable that will
    // later choose the FREQ1 register
    pRegister =
      0xD000; // Set D15 to 1 and D14 to 1 and D13 to 1 for the PHASE register
  }
  writeCtrlReg();
}

/*
void AD9833::lcdDebugInit(LiquidCrystal_I2C *_debugger) {
  debugger = _debugger;
  debugging = true;
}

void AD9833::lcdDebug(String message) {
  if (debugging) {
    debugger->setCursor(0, 1);
    debugger->print(message);
  }
}
*/

/*
 * Rotary encoder library for Arduino.
 */

#ifndef rotary_h
#define rotary_h

#include "Arduino.h"

// Enable this to emit codes twice per step.
//#define HALF_STEP

// Enable weak pullups
#define ENABLE_PULLUPS

// Values returned by 'process'
// No complete step yet.
#define DIR_NONE 0x0
// Clockwise step.
#define DIR_CW 0x10
// Anti-clockwise step.
#define DIR_CCW 0x20

class Rotary
{
  public:
    Rotary(char, char);
    // Process pin(s)
    unsigned char process();
  private:
    unsigned char state;
    unsigned char pin1;
    unsigned char pin2;
};

#endif
 

/* Rotary encoder handler for arduino. v1.1
 *
 * Copyright 2011 Ben Buxton. Licenced under the GNU GPL Version 3.
 * Contact: bb@cactii.net
 *
 * A typical mechanical rotary encoder emits a two bit gray code
 * on 3 output pins. Every step in the output (often accompanied
 * by a physical 'click') generates a specific sequence of output
 * codes on the pins.
 *
 * There are 3 pins used for the rotary encoding - one common and
 * two 'bit' pins.
 *
 * The following is the typical sequence of code on the output when
 * moving from one step to the next:
 *
 *   Position   Bit1   Bit2
 *   ----------------------
 *     Step1     0      0
 *      1/4      1      0
 *      1/2      1      1
 *      3/4      0      1
 *     Step2     0      0
 *
 * From this table, we can see that when moving from one 'click' to
 * the next, there are 4 changes in the output code.
 *
 * - From an initial 0 - 0, Bit1 goes high, Bit0 stays low.
 * - Then both bits are high, halfway through the step.
 * - Then Bit1 goes low, but Bit2 stays high.
 * - Finally at the end of the step, both bits return to 0.
 *
 * Detecting the direction is easy - the table simply goes in the other
 * direction (read up instead of down).
 *
 * To decode this, we use a simple state machine. Every time the output
 * code changes, it follows state, until finally a full steps worth of
 * code is received (in the correct order). At the final 0-0, it returns
 * a value indicating a step in one direction or the other.
 *
 * It's also possible to use 'half-step' mode. This just emits an event
 * at both the 0-0 and 1-1 positions. This might be useful for some
 * encoders where you want to detect all positions.
 *
 * If an invalid state happens (for example we go from '0-1' straight
 * to '1-0'), the state machine resets to the start until 0-0 and the
 * next valid codes occur.
 *
 * The biggest advantage of using a state machine over other algorithms
 * is that this has inherent debounce built in. Other algorithms emit spurious
 * output with switch bounce, but this one will simply flip between
 * sub-states until the bounce settles, then continue along the state
 * machine.
 * A side effect of debounce is that fast rotations can cause steps to
 * be skipped. By not requiring debounce, fast rotations can be accurately
 * measured.
 * Another advantage is the ability to properly handle bad state, such
 * as due to EMI, etc.
 * It is also a lot simpler than others - a static state table and less
 * than 10 lines of logic.
 */

#include "Arduino.h"
#include "Rotary.h"

/*
 * The below state table has, for each state (row), the new state
 * to set based on the next encoder output. From left to right in,
 * the table, the encoder outputs are 00, 01, 10, 11, and the value
 * in that position is the new state to set.
 */

#define R_START 0x0

#ifdef HALF_STEP
// Use the half-step state table (emits a code at 00 and 11)
#define R_CCW_BEGIN 0x1
#define R_CW_BEGIN 0x2
#define R_START_M 0x3
#define R_CW_BEGIN_M 0x4
#define R_CCW_BEGIN_M 0x5
const unsigned char ttable[6][4] = {
  // R_START (00)
  {R_START_M,            R_CW_BEGIN,     R_CCW_BEGIN,  R_START},
  // R_CCW_BEGIN
  {R_START_M | DIR_CCW, R_START,        R_CCW_BEGIN,  R_START},
  // R_CW_BEGIN
  {R_START_M | DIR_CW,  R_CW_BEGIN,     R_START,      R_START},
  // R_START_M (11)
  {R_START_M,            R_CCW_BEGIN_M,  R_CW_BEGIN_M, R_START},
  // R_CW_BEGIN_M
  {R_START_M,            R_START_M,      R_CW_BEGIN_M, R_START | DIR_CW},
  // R_CCW_BEGIN_M
  {R_START_M,            R_CCW_BEGIN_M,  R_START_M,    R_START | DIR_CCW},
};
#else
// Use the full-step state table (emits a code at 00 only)
#define R_CW_FINAL 0x1
#define R_CW_BEGIN 0x2
#define R_CW_NEXT 0x3
#define R_CCW_BEGIN 0x4
#define R_CCW_FINAL 0x5
#define R_CCW_NEXT 0x6

const unsigned char ttable[7][4] = {
  // R_START
  {R_START,    R_CW_BEGIN,  R_CCW_BEGIN, R_START},
  // R_CW_FINAL
  {R_CW_NEXT,  R_START,     R_CW_FINAL,  R_START | DIR_CW},
  // R_CW_BEGIN
  {R_CW_NEXT,  R_CW_BEGIN,  R_START,     R_START},
  // R_CW_NEXT
  {R_CW_NEXT,  R_CW_BEGIN,  R_CW_FINAL,  R_START},
  // R_CCW_BEGIN
  {R_CCW_NEXT, R_START,     R_CCW_BEGIN, R_START},
  // R_CCW_FINAL
  {R_CCW_NEXT, R_CCW_FINAL, R_START,     R_START | DIR_CCW},
  // R_CCW_NEXT
  {R_CCW_NEXT, R_CCW_FINAL, R_CCW_BEGIN, R_START},
};
#endif

/*
 * Constructor. Each arg is the pin number for each encoder contact.
 */
Rotary::Rotary(char _pin1, char _pin2) {
  // Assign variables.
  pin1 = _pin1;
  pin2 = _pin2;
  // Set pins to input.
  pinMode(pin1, INPUT);
  pinMode(pin2, INPUT);
#ifdef ENABLE_PULLUPS
  digitalWrite(pin1, HIGH);
  digitalWrite(pin2, HIGH);
#endif
  // Initialise state.
  state = R_START;
}

unsigned char Rotary::process() {
  // Grab state of input pins.
  unsigned char pinstate = (digitalRead(pin2) << 1) | digitalRead(pin1);
  // Determine new state from the pins and state table.
  state = ttable[state & 0xf][pinstate];
  // Return emit bits, ie the generated event.
  return state & 0x30;
}