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