/*
   Paparazzi mcu0 adc functions

   Copied from autopilot (autopilot.sf.net) thanx alot Trammell

   Copyright (C) 2002 Trammell Hudson <hudson@rotomotion.com>
   Copyright (C) 2003 Pascal Brisset, Antoine Drouin

   This file is part of paparazzi.

   paparazzi is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   paparazzi is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with paparazzi; see the file COPYING.  If not, write to
   the Free Software Foundation, 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.

*/


#include <arch/signal.h>
#include <arch/interrupt.h>
#include <arch/io.h>
#include "airframe.h"
#include "std.h"
#include "adc.h"


/*************************************************************************

    Analog to digital conversion code.

   We allow interrupts during the 2048 usec windows.  If we run the
   ADC clock faster than Clk/64 we have too much overhead servicing
   the interrupts from it and end up with servo jitter.

   For now we've slowed the clock to Clk/128 because it lets us
   be lazy in the interrupt routine.
*/
#define VOLTAGE_TIME  0x07
#define ANALOG_PORT PORTF
#define ANALOG_PORT_DIR DDRF


#ifdef CTL_BRD_V1_1
#define ANALOG_VREF 0
#endif

#if defined CTL_BRD_V1_2 || defined CTL_BRD_V1_2_1
#define ANALOG_VREF _BV(REFS0)
#endif

uint16_t    adc_samples[ NB_ADC ];

static struct adc_buf *buffers[ NB_ADC ];

void adc_buf_channel( uint8_t adc_channel, struct adc_buf *s )
{
  buffers[ adc_channel ] = s;
}

void
adc_init( void )
{
  uint8_t i;
  /* Ensure that our port is for input with no pull-ups */
  ANALOG_PORT   = 0x00;
  ANALOG_PORT_DIR = 0x00;

  /* Select our external voltage ref, which is tied to Vcc */
  ADMUX   = ANALOG_VREF;

  /* Turn off the analog comparator */
  sbi( ACSR, ACD );

  /* Select out clock, turn on the ADC interrupt and start conversion */
  ADCSR   = 0
            | VOLTAGE_TIME
            | ( 1 << ADEN )
            | ( 1 << ADIE )
            | ( 1 << ADSC );

  /* Init to 0 (usefull ?) */
  _Pragma( "loopbound min 8 max 8" )
  for ( i = 0; i < NB_ADC; i++ )
    buffers[ i ] = ( struct adc_buf * )0;
}

/**
   Called when the voltage conversion is finished

    8.913kHz on mega128@16MHz 1kHz/channel ??
*/


SIGNAL( SIG_ADC )
{
  uint8_t adc_input = ADMUX & 0x7;
  struct adc_buf *buf = buffers[ adc_input ];
  uint16_t adc_value = ADCW;
  /* Store result */
  adc_samples[ adc_input ] = adc_value;

  if ( buf ) {
    uint8_t new_head = buf->head + 1;
    if ( new_head >= AV_NB_SAMPLE ) new_head = 0;
    buf->sum -= buf->values[ new_head ];
    buf->values[ new_head ] = adc_value;
    buf->sum += adc_value;
    buf->head = new_head;
  }

  /* Find the next input */
  adc_input++;
  if ( adc_input >= 8 )
    adc_input = 0;
  /* Select it */
  ADMUX = adc_input | ANALOG_VREF;
  /* Restart the conversion */
  sbi( ADCSR, ADSC );

}