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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006 by Barry Wardell
*
* This program 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
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "adc.h"
#include "kernel.h"
#include "ascodec.h"
#include "as3514.h"
/* Read 10-bit channel data */
unsigned short adc_read(int channel)
{
unsigned short data = 0;
if ((unsigned)channel >= NUM_ADC_CHANNELS)
return 0;
ascodec_lock();
/* Select channel */
if (ascodec_write(AS3514_ADC_0, (channel << 4)) >= 0)
{
unsigned char buf[2];
/*
* The AS3514 ADC will trigger an interrupt when the conversion
* is finished, if the corresponding enable bit in IRQ_ENRD2
* is set.
* Previously the code did not wait and this apparently did
* not pose any problems, but this should be more correct.
* Without the wait the data read back may be completely or
* partially (first one of the two bytes) stale.
*/
ascodec_wait_adc_finished();
/* Read data */
if (ascodec_readbytes(AS3514_ADC_0, 2, buf) >= 0)
{
data = (((buf[0] & 0x3) << 8) | buf[1]);
}
}
ascodec_unlock();
return data;
}
void adc_init(void)
{
}
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