Arduino for STM32

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// Here is the sine wave.  It is a one cycle of sine tone, 255 8 bit samples, in hex values
// you could put any wave form you line in here...
uint8_t sineTable[]={
  0x80,0x83,0x86,0x89,0x8c,0x8f,0x92,0x95,0x98,0x9c,0x9f,0xa2,0xa5,0xa8,0xab,0xae,
  0xb0,0xb3,0xb6,0xb9,0xbc,0xbf,0xc1,0xc4,0xc7,0xc9,0xcc,0xce,0xd1,0xd3,0xd5,0xd8,
  0xda,0xdc,0xde,0xe0,0xe2,0xe4,0xe6,0xe8,0xea,0xec,0xed,0xef,0xf0,0xf2,0xf3,0xf5,
  0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfc,0xfd,0xfe,0xfe,0xff,0xff,0xff,0xff,0xff,
  0xff,0xff,0xff,0xff,0xff,0xff,0xfe,0xfe,0xfd,0xfc,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,
  0xf6,0xf5,0xf3,0xf2,0xf0,0xef,0xed,0xec,0xea,0xe8,0xe6,0xe4,0xe2,0xe0,0xde,0xdc,
  0xda,0xd8,0xd5,0xd3,0xd1,0xce,0xcc,0xc9,0xc7,0xc4,0xc1,0xbf,0xbc,0xb9,0xb6,0xb3,
  0xb0,0xae,0xab,0xa8,0xa5,0xa2,0x9f,0x9c,0x98,0x95,0x92,0x8f,0x8c,0x89,0x86,0x83,
  0x80,0x7c,0x79,0x76,0x73,0x70,0x6d,0x6a,0x67,0x63,0x60,0x5d,0x5a,0x57,0x54,0x51,
  0x4f,0x4c,0x49,0x46,0x43,0x40,0x3e,0x3b,0x38,0x36,0x33,0x31,0x2e,0x2c,0x2a,0x27,
  0x25,0x23,0x21,0x1f,0x1d,0x1b,0x19,0x17,0x15,0x13,0x12,0x10,0x0f,0x0d,0x0c,0x0a,
  0x09,0x08,0x07,0x06,0x05,0x04,0x03,0x03,0x02,0x01,0x01,0x00,0x00,0x00,0x00,0x00,
  0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x01,0x02,0x03,0x03,0x04,0x05,0x06,0x07,0x08,
  0x09,0x0a,0x0c,0x0d,0x0f,0x10,0x12,0x13,0x15,0x17,0x19,0x1b,0x1d,0x1f,0x21,0x23,
  0x25,0x27,0x2a,0x2c,0x2e,0x31,0x33,0x36,0x38,0x3b,0x3e,0x40,0x43,0x46,0x49,0x4c,
  0x4f,0x51,0x54,0x57,0x5a,0x5d,0x60,0x63,0x67,0x6a,0x6d,0x70,0x73,0x76,0x79,0x7c};

// final sample that goes tote DAC
uint16_t sample;

// the two bytes that go to the DAC over SPI
uint8_t dacSPI0;
uint8_t dacSPI1;

// variables for oscillators
uint16_t accumulator = 0;  // large number holds phase
uint8_t index = 0;        // index for wave lookup (the upper 8 bits of the accumulator)
uint16_t oscil = 8;        // oscillator output

#define PP_LED 8   // LED on pocket piano

// holds frequency value used for oscillator in phase steps
// this is an integer proportial to Hertz in the following way:
// frequency  = (FrequencyInHertz * 65536) / SampleRate, here sample rate is 15625
uint32_t frequency = 0;

uint8_t gain = 0xff;      // gain of oscillator

int pitchScale;

void setup(){

  //Timer2 setup  This is the audio rate timer, fires an interrupt at 15625 Hz sampling rate
  TIMSK2 = 1<<OCIE2A;  // interrupt enable audio timer
  OCR2A = 127;
  TCCR2A = 2;               // CTC mode, counts up to 127 then resets
  TCCR2B = 0<<CS22 | 1<<CS21 | 0<<CS20;   // different for atmega8 (no 'B' i think)
  SPCR = 0x50;   // set up SPI port
  SPSR = 0x01;
  DDRB |= 0x2E;       // PB output for DAC CS, and SPI port
  PORTB |= (1<<1);
  //led
  pinMode(PP_LED, OUTPUT);

  Serial.begin(9600);
  Serial.println("hello");
  Serial.println("welcome to synthesizer");
//
  sei();			// global interrupt enable
}


void loop(void)
{
  
  float frequencyInHertz = 440.0;   // use this to hold a frequency in hertz
                                    // normally we wouldn't use floats, and just use integers,
                                    // but it is convinient here to show freqency calculation

  // using formula above, calculate correct oscillator frequency value
  frequency =  (frequencyInHertz * 65536.0) / 15625.0; 
  Serial.println("playing");
}

// timer 2 is audio interrupt timer
ISR(TIM2_COMPA_vect) {
  OCR2A = 127;
  
  // calculate frequency mod
  accumulator = accumulator + frequency;  // add in pith, the higher the number, the faster it rolls over, the more cycles per second
  index = accumulator >> 8;   // use top 8 bits as wavetable index

  oscil = sineTable[index];    // get sample from wave table

  sample = oscil << 8;   // sample format for DAC is 12 bit, left justified

  // format sample for SPI port
  dacSPI0 = sample >> 8;
  dacSPI0 >>= 4;
  dacSPI0 |= 0x30;
  dacSPI1 = sample >> 4;

  // transmit value out the SPI port
  PORTB &= ~(1<<1); // Frame sync low
  SPDR = dacSPI0;
  while (!(SPSR & (1<<SPIF)));
  SPDR = dacSPI1;
  while (!(SPSR & (1<<SPIF)));
  PORTB |= (1<<1); // Frame sync high
}

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#include <SPI.h>
void setup() {
   SPI.begin();
  SPI.beginTransaction(SPISettings(36000000, MSBFIRST, SPI_MODE0)); // must be called after SPI.begin() 
}
void loop() {
   SPI.transfer(x);  // send byte
}

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#define LED_RATE 500000    // in microseconds; should give 0.5Hz toggles

// We'll use timer 2
HardwareTimer timer(2);

void setup() {
    // Set up the LED to blink
    pinMode(BOARD_LED_PIN, OUTPUT);

    // Pause the timer while we're configuring it
    timer.pause();

    // Set up period
    timer.setPeriod(LED_RATE); // in microseconds

    // Set up an interrupt on channel 1
    timer.setChannel1Mode(TIMER_OUTPUT_COMPARE);
    timer.setCompare(TIMER_CH1, 1);  // Interrupt 1 count after each update
    timer.attachCompare1Interrupt(handler_led);

    // Refresh the timer's count, prescale, and overflow
    timer.refresh();

    // Start the timer counting
    timer.resume();
}

void loop() {
    // Nothing! It's all in the handler_led() interrupt:
}

void handler_led(void) {
    toggleLED();
}