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/* AT91 ADC for OpenPICC
* (C) 2007 Henryk Plötz <henryk@ploetzli.ch>
*
* 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 program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "openpicc.h"
#include "board.h"
#include <sys/types.h>
#include <lib_AT91SAM7.h>
static AT91S_ADC* adc = AT91C_BASE_ADC;
int adc_get_field_strength(void)
{
adc->ADC_CR = AT91C_ADC_START;
while( (adc->ADC_SR & AT91C_ADC_EOC4)==0) ;
return adc->ADC_CDR4;
}
void adc_init(void)
{
// PRESCAL = 4 -> ADC clock = MCLK / 10 = 4.8 MHz (max is 5 MHz at 10 bit)
// Start time <20 us -> STARTUP=11
// Track and hold time >600 ns -> SHTIM=2
adc->ADC_MR = AT91C_ADC_TRGEN_DIS | AT91C_ADC_LOWRES_10_BIT |
AT91C_ADC_SLEEP_MODE | (4 << 8) | (11 << 16) | (2 << 24);
adc->ADC_IDR = 0xfffff;
adc->ADC_CHER = OPENPICC_ADC_FIELD_STRENGTH;
}
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