93 lines
2.5 KiB
C
93 lines
2.5 KiB
C
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/***************************************************************************
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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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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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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 "config.h"
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#include "cpu.h"
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#include "system.h"
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#include "kernel.h"
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#include "thread.h"
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#include "adc.h"
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static unsigned short adcdata[NUM_ADC_CHANNELS];
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/* Scan ADC so that adcdata[channel] gets updated */
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unsigned short adc_scan(int channel)
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{
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unsigned int adc_data_1;
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unsigned int adc_data_2;
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/* Initialise */
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ADC_ADDR=0x130;
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ADC_STATUS=0; /* 4 bytes, 1 per channel. Each byte is 0 if the channel is
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off, 0x40 if the channel is on */
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/* Enable Channel */
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ADC_ADDR |= (0x1000000<<channel);
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/* Start? */
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ADC_ADDR |= 0x20000000;
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ADC_ADDR |= 0x80000000;
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/* ADC_DATA_1 and ADC_DATA_2 are both four bytes, one byte per channel.
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For each channel, ADC_DATA_1 stores the 8-bit msb, ADC_DATA_2 stores the
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2-bit lsb (in bits 0 and 1). Each channel is 10 bits total. */
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adc_data_1 = ((ADC_DATA_1 >> (8*channel)) & 0xff);
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adc_data_2 = ((ADC_DATA_2 >> (8*channel+6)) & 0x3);
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adcdata[channel] = (adc_data_1<<2 | adc_data_2);
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return adcdata[channel];
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}
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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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return adcdata[channel];
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}
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static int adc_counter;
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static void adc_tick(void)
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{
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if(++adc_counter == HZ)
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{
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adc_counter = 0;
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adc_scan(ADC_0);
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adc_scan(ADC_1);
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adc_scan(ADC_2);
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adc_scan(ADC_3);
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}
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}
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void adc_init(void)
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{
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/* Enable ADC */
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ADC_ENABLE_ADDR |= ADC_ENABLE;
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/* Initialise */
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ADC_INIT=0;
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/* Force a scan of all channels to get initial values */
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adc_scan(ADC_0);
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adc_scan(ADC_1);
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adc_scan(ADC_2);
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adc_scan(ADC_3);
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tick_add_task(adc_tick);
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}
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