openpcd/openpicc/application/adc.c @ master
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/* AT91 ADC for OpenPICC
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* (C) 2007 Henryk Plötz <henryk@ploetzli.ch>
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*
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* This program 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 of the License, or
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* (at your option) any later version.
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*
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* This program 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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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include "openpicc.h"
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#include "board.h"
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#include <sys/types.h>
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#include <lib_AT91SAM7.h>
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static AT91S_ADC* adc = AT91C_BASE_ADC; |
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int adc_get_field_strength(void) |
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{
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adc->ADC_CR = AT91C_ADC_START; |
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while( (adc->ADC_SR & AT91C_ADC_EOC4)==0) ; |
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return adc->ADC_CDR4; |
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}
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void adc_init(void) |
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{
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// PRESCAL = 4 -> ADC clock = MCLK / 10 = 4.8 MHz (max is 5 MHz at 10 bit)
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// Start time <20 us -> STARTUP=11
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// Track and hold time >600 ns -> SHTIM=2
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adc->ADC_MR = AT91C_ADC_TRGEN_DIS | AT91C_ADC_LOWRES_10_BIT | |
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AT91C_ADC_SLEEP_MODE | (4 << 8) | (11 << 16) | (2 << 24); |
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adc->ADC_IDR = 0xfffff; |
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adc->ADC_CHER = OPENPICC_ADC_FIELD_STRENGTH; |
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}
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