a752c7ab
 elopes
add first test an...
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/*
* Copyright (C) 2016 Fundacion Inria Chile
*
* 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_stm32l1
* @ingroup drivers_periph_adc
* @{
*
* @file
* @brief Low-level ADC driver implementation
*
* @author Francisco Molina <francisco.molina@inria.cl>
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @author Nick v. IJzendoorn <nijzendoorn@engineering-spirit.nl>
*
* @}
*/
#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 STM32l1 CPU's have single ADC device
*/
static mutex_t lock = MUTEX_INIT;
static inline void prep(void)
{
mutex_lock(&lock);
RCC->APB2ENR |= RCC_APB2ENR_ADC1EN;
}
static inline void done(void)
{
RCC->APB2ENR &= ~(RCC_APB2ENR_ADC1EN);
mutex_unlock(&lock);
}
int adc_init(adc_t line)
{
uint32_t clk_div = 2;
/* check if the line is valid */
if (line >= ADC_NUMOF) {
return -1;
}
/* lock and power-on the device */
prep();
/* configure the pin */
if ((adc_config[line].pin != GPIO_UNDEF))
gpio_init_analog(adc_config[line].pin);
/* set clock prescaler to get the maximal possible ADC clock value */
for (clk_div = 2; clk_div < 8; clk_div += 2) {
if ((CLOCK_CORECLOCK / clk_div) <= MAX_ADC_SPEED) {
break;
}
}
ADC->CCR = ((clk_div / 2) - 1) << 16;
/* check if this channel is an internal ADC channel, if so
* enable the internal temperature and Vref */
if (adc_config[line].chan == 16 || adc_config[line].chan == 17) {
ADC->CCR |= ADC_CCR_TSVREFE;
}
/* enable the ADC module */
ADC1->CR2 = ADC_CR2_ADON;
/* turn off during idle phase*/
ADC1->CR1 = ADC_CR1_PDI;
/* free the device again */
done();
return 0;
}
int adc_sample(adc_t line, adc_res_t res)
{
int sample;
/* check if resolution is applicable */
if ( (res != ADC_RES_6BIT) &&
(res != ADC_RES_8BIT) &&
(res != ADC_RES_10BIT) &&
(res != ADC_RES_12BIT)) {
return -1;
}
/* lock and power on the ADC device */
prep();
/* set resolution, conversion channel and single read */
ADC1->CR1 |= res & ADC_CR1_RES;
ADC1->SQR1 &= ~ADC_SQR1_L;
ADC1->SQR5 = adc_config[line].chan;
/* wait for regulat channel to be ready*/
while (!(ADC1->SR & ADC_SR_RCNR)) {}
/* start conversion and wait for results */
ADC1->CR2 |= ADC_CR2_SWSTART;
while (!(ADC1->SR & ADC_SR_EOC)) {}
/* finally read sample and reset the STRT bit in the status register */
sample = (int)ADC1->DR;
ADC1 -> SR &= ~ADC_SR_STRT;
/* power off and unlock device again */
done();
return sample;
}
#else
typedef int dont_be_pedantic;
#endif /* ADC_CONFIG */
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