OpenRTX/platform/drivers/ADC/ADC1_Mod17.c

94 wiersze
3.2 KiB
C

/***************************************************************************
* Copyright (C) 2020 - 2022 by Silvano Seva IU2KWO *
* and Niccolò Izzo IU2KIN *
* *
* 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 3 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, see <http://www.gnu.org/licenses/> *
***************************************************************************/
#include <interfaces/gpio.h>
#include <hwconfig.h>
#include <pthread.h>
#include <stdlib.h>
#include "ADC1_Mod17.h"
pthread_mutex_t adcMutex;
void adc1_init()
{
pthread_mutex_init(&adcMutex, NULL);
RCC->APB2ENR |= RCC_APB2ENR_ADC1EN;
__DSB();
/*
* Configure GPIOs to analog input mode:
*/
gpio_setMode(AIN_VBAT, INPUT_ANALOG);
/*
* ADC clock is APB2 frequency divided by 8, giving 10.5MHz.
* We set the sample time of each channel to 84 ADC cycles and we have that
* a conversion takes 12 cycles: total conversion time is then of ~9us.
*/
ADC->CCR |= ADC_CCR_ADCPRE;
ADC1->SMPR2 = ADC_SMPR2_SMP3_2;
/*
* Convert one channel, no overrun interrupt, 12-bit resolution,
* no analog watchdog, discontinuous mode, no end of conversion interrupts,
* turn on ADC.
*/
ADC1->SQR1 = 0;
ADC1->CR2 = ADC_CR2_ADON;
}
void adc1_terminate()
{
pthread_mutex_destroy(&adcMutex);
ADC1->CR2 &= ~ADC_CR2_ADON;
RCC->APB2ENR &= ~RCC_APB2ENR_ADC1EN;
__DSB();
}
uint16_t adc1_getRawSample(uint8_t ch)
{
if(ch > 15) return 0;
pthread_mutex_lock(&adcMutex);
ADC1->SQR3 = ch;
ADC1->CR2 |= ADC_CR2_SWSTART;
while((ADC1->SR & ADC_SR_EOC) == 0) ;
uint16_t value = ADC1->DR;
pthread_mutex_unlock(&adcMutex);
return value;
}
uint16_t adc1_getMeasurement(uint8_t ch)
{
/*
* To avoid using floats, we convert the raw ADC sample to mV using 16.16
* fixed point math. The equation for conversion is (sample * 3300)/4096 but,
* since converting the raw ADC sample to 16.16 notation requires a left
* shift by 16 and dividing by 4096 is equivalent to shifting right by 12,
* we just shift left by four and then multiply by 3300.
* With respect to using floats, maximum error is -1mV.
*/
uint32_t sample = (adc1_getRawSample(ch) << 4) * 3300;
return ((uint16_t) (sample >> 16));
}