#include <Arduino.h>
#include <SPI.h>
#include "dac.h"



//#define USE_SPI


#ifdef USE_SPI

#define CS_PIN    10  // SYNC
#define LDAC_PIN  8


#define MODEBIT_PD0  0x1000
#define MODEBIT_PD1  0x2000
#define MODEBIT_BUF  0x4000
#define MODEBIT_ChB  0x8000


#else

#define DAC_PIN   DAC0

#endif // USE_SPI







void dac_init()
{

#if defined(USE_SPI)

    pinMode(CS_PIN, OUTPUT);
    digitalWrite(CS_PIN, HIGH);

    pinMode(LDAC_PIN, OUTPUT);
    digitalWrite(LDAC_PIN, HIGH);

    SPI.begin();
    SPI.setBitOrder(MSBFIRST);
    SPI.setDataMode(SPI_MODE1);

#else

    pinMode(DAC_PIN, OUTPUT);
    analogWriteResolution(12);

#endif // __SAM3X8E__
}


void dac_write(uint32_t dac)
{
    uint32_t value = dac;

#if defined(USE_SPI)

    //value |= MODEBIT_ChB; // channel B

    digitalWrite(CS_PIN, LOW);
    delay(1);
    SPI.transfer((value >> 8) & 0xFF);
    SPI.transfer(value & 0xFF);
    digitalWrite(CS_PIN, HIGH);

    digitalWrite(LDAC_PIN, LOW);
    delay(1);
    digitalWrite(LDAC_PIN, HIGH);

#else

    analogWrite(DAC_PIN, value);

#endif //  __SAM3X8E__
}