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#include "Atmega128rfa1.h"

extern "C"

{

#include <avr/io.h>

#include <avr/interrupt.h>

  void __cxa_pure_virtual(void) {}

}

unsigned long millis;

int rx_start = 0, rx_end = 0;

char rx_buffer[RX_BUFFER_SIZE];

Atmega128rfa1::Atmega128rfa1()

{

}

ISR(TIMER0_COMPA_vect)

{

  millis++;

}

ISR(USART_RX_vect)

{

  char data = UDR0;

  if (rx_end == rx_start-1 || (rx_start == 0 && rx_end == RX_BUFFER_SIZE-1))

  {

    // TODO warn of buffer overflow?

  }

  else

  {

    rx_buffer[rx_end] = data;

    rx_end++;

    if (rx_end == RX_BUFFER_SIZE)

      rx_end = 0;

  }

}

void Atmega128rfa1::init()

{

  // === init serial ===

  // baud = F_CPU / (16 (UBRR + 1))

  uint16_t ubrr = F_CPU / 16 / 38400 - 1;

  UBRR0H = ubrr >> 8;

  UBRR0L = ubrr;

  // UMSEL0 = 0, asynchronous usart

  // UPM0 = 0, parity check disabled

  // USBS0 = 0, 1 stop bit

  // UCSZ0 = 3, 8-bit

  UCSR0B = _BV(RXCIE0) | _BV(RXEN0) | _BV(TXEN0);

  UCSR0C = _BV(UCSZ01) | _BV(UCSZ00);

  // === init time ===

  // COM0x = 0, pin OC0x not used

  // WGM0 = 2, clear timer on compare match, TOP = OCRA

  // CS0 = 3, 64 prescaler

  TCCR0A = _BV(WGM01);

  TCCR0B = _BV(CS01) | _BV(CS00);

  // enable interrupt on compare match A

  TIMSK0 = _BV(OCIE0A);

  // (1 ms) * 16 MHz / 64 prescaler = 250

  //OCR0A = 250;

  // (1 ms) * 8 MHz / 64 prescaler = 125

  OCR0A = 125;

  millis = 0;

  sei();

}

int Atmega128rfa1::read()

{

  cli();

  if (rx_start == rx_end)

    return -1;

  else

  {

    int ret = rx_buffer[rx_start];

    rx_start++;

    if (rx_start == RX_BUFFER_SIZE)

      rx_start = 0;

    return ret;

  }

  sei();

}

void Atmega128rfa1::write(uint8_t* data, int length)

{

  // TODO make this non-blocking with a tx buffer

  int i;

  for (i = 0; i < length; i++)

  {

    while (!(UCSR0A & _BV(UDRE0)));

    UDR0 = data[i];

  }

}

unsigned long Atmega128rfa1::time()

{

  unsigned long ret;

  cli();

  ret = millis;

  sei();

  return ret;

}