/**
 * V. Hunter Adams ([email protected])
 */

#include "pico/stdlib.h"
#include <math.h>
#include "hardware/timer.h"
#include "hardware/irq.h"
#include <stdio.h>

#define ALARM_NUM 0
#define two32 4294967296.0 // 2^32 
#define Fs 50000
#define DELAY 20
volatile unsigned int phase_accum_main;
volatile unsigned int phase_incr_main = (100.0*two32)/Fs ;//
#define sine_table_size 256
volatile int sin_table[sine_table_size] ;
#define ALARM_IRQ TIMER_IRQ_0
// Main (runs on core 0)
uint16_t DAC_data;
void print_uint(uint32_t num) {
    char buf[10];
    int i = 0;
    if (num == 0) {
        putchar('0');
    } else {
        while (num > 0 && i < sizeof(buf)) {
            buf[i++] = '0' + (num % 10);
            num /= 10;
        }
        while (i--) {
            putchar(buf[i]);
        }
    }
    putchar(','); putchar(' ');
}
static void alarm_irq(void) {
    // Clear the alarm irq
    hw_clear_bits(&timer_hw->intr, 1u << ALARM_NUM);
      // Reset the alarm register
    timer_hw->alarm[ALARM_NUM] = timer_hw->timerawl + DELAY;
    // DDS phase and sine table lookup
	phase_accum_main += phase_incr_main  ;
    DAC_data= (sin_table[phase_accum_main>>24]+2048);
    print_uint(DAC_data);

}
int main() {
    // === build the sine lookup table =======
   	// scaled to produce values between 0 and 4096
    int ii;
    for (ii = 0; ii < sine_table_size; ii++){
         sin_table[ii] = (int)(2047*sin((float)ii*6.283/(float)sine_table_size));
    }
  stdio_init_all(); 
  // Enable the interrupt for the alarm (we're using Alarm 0)
    hw_set_bits(&timer_hw->inte, 1u << ALARM_NUM) ;
    // Associate an interrupt handler with the ALARM_IRQ
    irq_set_exclusive_handler(ALARM_IRQ, alarm_irq) ;
    // Enable the alarm interrupt
    irq_set_enabled(ALARM_IRQ, true) ;
    // Write the lower 32 bits of the target time to the alarm register, arming it.
    timer_hw->alarm[ALARM_NUM] = timer_hw->timerawl + DELAY ;
    // Initialize the LED pin
  
    // Loop
    while (true) {
       
    }
}