a752c7ab
 elopes
add first test an...
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/*
* Copyright (C) 2014-2016 Freie Universitรคt Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup cpu_stm32f0
* @ingroup drivers_periph_adc
* @{
*
* @file
* @brief Low-level ADC driver implementation
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
*
* @}
*/
#include "cpu.h"
#include "mutex.h"
#include "periph/adc.h"
#ifdef ADC_CONFIG
/**
* @brief Maximum allowed ADC clock speed
*/
#define MAX_ADC_SPEED (12000000U)
/**
* @brief Load the ADC configuration
*/
static const adc_conf_t adc_config[] = ADC_CONFIG;
/**
* @brief Allocate locks for all three available ADC device
*
* All STM32F0 CPUs we support so far only come with a single ADC device.
*/
static mutex_t lock = MUTEX_INIT;
static inline void prep(void)
{
mutex_lock(&lock);
periph_clk_en(APB2, RCC_APB2ENR_ADCEN);
}
static inline void done(void)
{
periph_clk_dis(APB2, RCC_APB2ENR_ADCEN);
mutex_unlock(&lock);
}
int adc_init(adc_t line)
{
/* make sure the given line is valid */
if (line >= ADC_NUMOF) {
return -1;
}
/* lock and power on the device */
prep();
/*configure the pin */
gpio_init_analog(adc_config[line].pin);
/* reset configuration */
ADC1->CFGR2 = 0;
/* enable device */
ADC1->CR = ADC_CR_ADEN;
/* configure sampling time to save value */
ADC1->SMPR = 0x3; /* 28.5 ADC clock cycles */
/* power off an release device for now */
done();
return 0;
}
int adc_sample(adc_t line, adc_res_t res)
{
int sample;
/* check if resolution is applicable */
if (res > 0xf0) {
return -1;
}
/* lock and power on the ADC device */
prep();
/* set resolution and channel */
ADC1->CFGR1 = res;
ADC1->CHSELR = (1 << adc_config[line].chan);
/* start conversion and wait for results */
ADC1->CR |= ADC_CR_ADSTART;
while (!(ADC1->ISR & ADC_ISR_EOC)) {}
/* read result */
sample = (int)ADC1->DR;
/* unlock and power off device again */
done();
return sample;
}
#else
typedef int dont_be_pedantic;
#endif /* ADC_CONFIG */
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