/*
 * ad9833 basic.cpp
 *
 * Created: 17/04/2018 18:18:25
 * Author : ed
 */ 

#define F_CPU 16000000L
#include <stdint.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include <stdlib.h>
#define USART_BAUDRATE 31250
#define UBRR_VALUE (((F_CPU / (USART_BAUDRATE * 16UL))) - 1)
#define IS_ODD(x)   ((x) & 1)
#define IS_EVEN(x)  (!(IS_ODD(x)))

/*name AD9833 command register bits */
#define AD_B28     0x2000
#define AD_HLB     0x1000
#define AD_FSELECT 0x0800
#define AD_PSELECT 0x0400
#define AD_RESET   0x0100
#define AD_SLEEP1  0x0080
#define AD_SLEEP12 0x0040
#define AD_OPBITEN 0x0020
#define AD_DIV2    0x0008

/* name AD9833 register addresses */
#define AD_FREQ0  0x4000
#define AD_FREQ1  0x8000
#define AD_PHASE0 0xC000
#define AD_PHASE1 0xE000
#define AD_SQUARE (0x2000 | 0x28)
#define AD_SINE   0x2000
#define AD_TRI    0x2002

/* chip select for AD9833 */
#define cs_AD9833_low	PORTB &= ~(1<<PB2);	//CS AD9833 low
#define cs_AD9833_high	PORTB |= (1<<PB2);	// high


/* name AD9833 calculation macros */
#define AD_F_MCLK 16000000 ///<Clock speed of the ad9833 reference clock
#define AD_2POW28 268435456 ///<used in calculating output freq

/* Macro that calculates the value for a ad9833 frequency register from a frequency */
#define AD_FREQ_CALC(calc_freq) (float)(((double)AD_2POW28/(double)AD_F_MCLK*calc_freq)*4)

/* name variables for setting the DDS */
volatile uint16_t wave_form;
volatile uint16_t high, low;
volatile uint32_t frequency_word;

void init(void)
{
	/* stop watchdog when enabled */
	MCUSR=0;
	WDTCSR|=(_BV(WDCE) | _BV(WDE));
	WDTCSR=0;
	DDRB |= (1<<DDB0)
	|(1<<DDB2)
	|(1<<DDB3)
	|(1<<DDB5); //outputs for spi
	PORTB |= (1<<PB0)
	|(1<<PB2)
	|(1<<PB3)
	|(1<<PB5); //cs + spi controls high
	/* set spi registers */
	SPCR = (1<<SPE)		// SPI enable
	|(1<<MSTR)			//master mode
	|(1<<CPOL)			//setup rising
	|(0<<CPHA)			//sample falling
	|(0<<SPR0);			// full speed
	SPSR = (1<<SPI2X);  //Double speed bit
}

void ad9833_send(uint16_t packet)
{
	cs_AD9833_low;						// drive CS low
	SPDR = ((packet>>8) & 0xFF);		// send high Byte
	while ( !(SPSR & (1<<SPIF))) {};	// ready?
	SPDR = (packet & 0x00FF);			// send low Byte
	while ( !(SPSR & (1<<SPIF))) {};	// ready?
	cs_AD9833_high;						// drive SS high again
}

void ad9833_set_frequency(float frequency_AD9833)
{
	frequency_word = AD_FREQ_CALC(frequency_AD9833);
	high = uint16_t (AD_FREQ0 | (0x3FFF&(uint16_t)(frequency_word>>16)));//HIGH word for DDS
	low = uint16_t (AD_FREQ0 | (0x3FFF&(uint16_t)(frequency_word>>2 )));//LOW word for DDS
	/* 
	wave shapes are: 
	AD_SINE, AD_SQUARE or AD_TRI
	remember: AD_SQUARE puts out a square of 0 - 5volt, while AD_TRI and AD_SINE puts out 0 - 0.65 volt
	*/	
	ad9833_send(AD_TRI);// set waveform shape
	ad9833_send(low);//low word
	ad9833_send(high);//high word
}


int main (void)
{
	init();
	ad9833_set_frequency(1500.1);
	while (1)
	{
	}
}