openpcd/openpicc/application/adc.c @ master
| 1 | ee1f0214 | henryk | /* AT91 ADC for OpenPICC
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| 2 | * (C) 2007 Henryk Plötz <henryk@ploetzli.ch>
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| 3 | *
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| 4 | * This program is free software; you can redistribute it and/or modify
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| 5 | * it under the terms of the GNU General Public License as published by
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| 6 | * the Free Software Foundation; either version 2 of the License, or
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| 7 | * (at your option) any later version.
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| 8 | *
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| 9 | * This program is distributed in the hope that it will be useful,
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| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 12 | * GNU General Public License for more details.
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| 13 | *
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| 14 | * You should have received a copy of the GNU General Public License
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| 15 | * along with this program; if not, write to the Free Software
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| 16 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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| 17 | *
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| 18 | */
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| 19 | |||
| 20 | |||
| 21 | #include "openpicc.h"
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| 22 | #include "board.h"
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| 23 | |||
| 24 | #include <sys/types.h>
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| 25 | #include <lib_AT91SAM7.h>
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| 26 | |||
| 27 | static AT91S_ADC* adc = AT91C_BASE_ADC; |
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| 28 | |||
| 29 | int adc_get_field_strength(void) |
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| 30 | {
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| 31 | adc->ADC_CR = AT91C_ADC_START; |
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| 32 | while( (adc->ADC_SR & AT91C_ADC_EOC4)==0) ; |
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| 33 | return adc->ADC_CDR4; |
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| 34 | }
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| 35 | |||
| 36 | void adc_init(void) |
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| 37 | {
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| 38 | // PRESCAL = 4 -> ADC clock = MCLK / 10 = 4.8 MHz (max is 5 MHz at 10 bit)
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| 39 | // Start time <20 us -> STARTUP=11
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| 40 | // Track and hold time >600 ns -> SHTIM=2
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| 41 | adc->ADC_MR = AT91C_ADC_TRGEN_DIS | AT91C_ADC_LOWRES_10_BIT | |
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| 42 | AT91C_ADC_SLEEP_MODE | (4 << 8) | (11 << 16) | (2 << 24); |
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| 43 | adc->ADC_IDR = 0xfffff; |
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| 44 | adc->ADC_CHER = OPENPICC_ADC_FIELD_STRENGTH; |
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| 45 | }
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