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/* USRP E310 Firmware Atmel AVR ADC driver
* Copyright (C) 2014 Ettus Research
* This file is part of the USRP E310 Firmware
* The USRP E310 Firmware 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.
* The USRP E310 Firmware 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 the USRP E310 Firmware. If not, see <http://www.gnu.org/licenses/>.
*/
#include <avr/io.h>
#include "adc.h"
#include "utils.h"
void adc_init(void)
{
/* disable digital input on PC0 (ADC0) */
DIDR0 |= 0x1;
/* set to AVcc reference, left aligned and ADC0 */
ADMUX = (1 << REFS0)
| (0 << ADLAR)
| (0 << MUX0);
/* prescale clock by 128 */
ADCSRA = BIT(ADPS2) | BIT(ADPS1) | BIT(ADPS0);
}
uint16_t adc_single_shot(void)
{
uint16_t value;
/* turn on ADC */
ADCSRA |= (1 << ADEN);
/* start conversion */
ADCSRA |= (1 << ADSC);
/* busy wait for conversion */
while (ADCSRA & (1 << ADSC)) {
};
/* we need to first read the lower bits,
* which will lock the value until higher bits are read */
value = (ADCL << 0);
value |= (ADCH << 8);
/* turn adc of again */
ADCSRA &= ~(1 << ADEN);
return value;
}
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