File content as of revision 2:4834d4483ea6:

/*
   Nucleo F767 DCO
   2018.07.22

*/
#include "mbed.h"

#include "wavetable_12bit_32k.h"
#define COUNT_OF_ENTRIES  (32768)

#define PIN_CHECK   (1)
#define UART_TRACE  (0)
#define TITLE_STR1  ("Nucleo F767 DCO")
#define TITLE_STR2  ("20180724")

// Pin Assign
AnalogOut Dac1(PA_4);
AnalogOut Dac2(PA_5);

#if (PIN_CHECK)
DigitalOut CheckPin(D4);
#endif

// Parameter
double drate = 1000.0;         // initial output rate (Hz)
const double refclk = 200000;  // Hz

// Interruput
Ticker ticker;

// DDS
volatile uint32_t phaccu;
volatile uint32_t tword_m;

//-------------------------------------------------------------------------------------------------
// Interrupt Service Routine
//

// param
//   val: 0 .. 4095
void InternalDacWrite(uint16_t val)
{
    // avoid distortion of built-in DAC
    uint16_t v = ((val + 1024) << 3);
    
    Dac2.write_u16(v);
}

void update()
{
#if (PIN_CHECK)
    CheckPin.write(1);
#endif

    phaccu = phaccu + tword_m;
    uint16_t idx = phaccu >> 17;  // use upper 15 bits
    
    InternalDacWrite(sin_12bit_32k[idx]);

#if (PIN_CHECK)
    CheckPin.write(0);
#endif
}

//-------------------------------------------------------------------------------------------------
// Main routine
//

int main()
{
    tword_m = pow(2.0, 32) * drate / refclk;  // calculate DDS tuning word;
    
    float interruptPeriodUs = 1000000.0 / refclk; 
    ticker.attach_us(&update, interruptPeriodUs);
    
    while (1) {
    }
}