131 lines
3.2 KiB
C
131 lines
3.2 KiB
C
/*
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Paparazzi mcu0 adc functions
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Copied from autopilot (autopilot.sf.net) thanx alot Trammell
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Copyright (C) 2002 Trammell Hudson <hudson@rotomotion.com>
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Copyright (C) 2003 Pascal Brisset, Antoine Drouin
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This file is part of paparazzi.
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paparazzi is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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paparazzi is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with paparazzi; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA.
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*/
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#include <arch/signal.h>
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#include <arch/interrupt.h>
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#include <arch/io.h>
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#include "airframe.h"
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#include "std.h"
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#include "adc.h"
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/*************************************************************************
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Analog to digital conversion code.
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We allow interrupts during the 2048 usec windows. If we run the
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ADC clock faster than Clk/64 we have too much overhead servicing
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the interrupts from it and end up with servo jitter.
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For now we've slowed the clock to Clk/128 because it lets us
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be lazy in the interrupt routine.
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*/
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#define VOLTAGE_TIME 0x07
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#define ANALOG_PORT PORTF
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#define ANALOG_PORT_DIR DDRF
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#ifdef CTL_BRD_V1_1
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#define ANALOG_VREF 0
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#endif
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#if defined CTL_BRD_V1_2 || defined CTL_BRD_V1_2_1
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#define ANALOG_VREF _BV(REFS0)
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#endif
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uint16_t adc_samples[ NB_ADC ];
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static struct adc_buf *buffers[ NB_ADC ];
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void adc_buf_channel( uint8_t adc_channel, struct adc_buf *s )
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{
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buffers[ adc_channel ] = s;
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}
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void
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adc_init( void )
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{
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uint8_t i;
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/* Ensure that our port is for input with no pull-ups */
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ANALOG_PORT = 0x00;
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ANALOG_PORT_DIR = 0x00;
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/* Select our external voltage ref, which is tied to Vcc */
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ADMUX = ANALOG_VREF;
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/* Turn off the analog comparator */
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sbi( ACSR, ACD );
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/* Select out clock, turn on the ADC interrupt and start conversion */
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ADCSR = 0
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| VOLTAGE_TIME
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| ( 1 << ADEN )
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| ( 1 << ADIE )
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| ( 1 << ADSC );
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/* Init to 0 (usefull ?) */
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_Pragma( "loopbound min 8 max 8" )
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for ( i = 0; i < NB_ADC; i++ )
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buffers[ i ] = ( struct adc_buf * )0;
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}
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/**
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Called when the voltage conversion is finished
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8.913kHz on mega128@16MHz 1kHz/channel ??
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*/
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SIGNAL( SIG_ADC )
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{
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uint8_t adc_input = ADMUX & 0x7;
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struct adc_buf *buf = buffers[ adc_input ];
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uint16_t adc_value = ADCW;
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/* Store result */
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adc_samples[ adc_input ] = adc_value;
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if ( buf ) {
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uint8_t new_head = buf->head + 1;
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if ( new_head >= AV_NB_SAMPLE ) new_head = 0;
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buf->sum -= buf->values[ new_head ];
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buf->values[ new_head ] = adc_value;
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buf->sum += adc_value;
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buf->head = new_head;
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}
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/* Find the next input */
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adc_input++;
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if ( adc_input >= 8 )
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adc_input = 0;
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/* Select it */
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ADMUX = adc_input | ANALOG_VREF;
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/* Restart the conversion */
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sbi( ADCSR, ADSC );
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}
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