/***************************************************************************
* Copyright (C) 2020 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 *
***************************************************************************/
#include
#include "ADC0_GDx.h"
void adc0_init()
{
SIM->SCGC6 |= SIM_SCGC6_ADC0(1);
ADC0->CFG1 |= ADC_CFG1_ADIV(3) /* Divide clock by 8 */
| ADC_CFG1_ADLSMP(1) /* Long sample time */
| ADC_CFG1_MODE(3); /* 16 bit result */
ADC0->SC3 |= ADC_SC3_AVGE(1) /* Enable hardware average */
| ADC_SC3_AVGS(3); /* Average over 32 samples */
/* Calibrate ADC */
ADC0->SC3 |= ADC_SC3_CAL(1);
while((ADC0->SC3) & ADC_SC3_CAL_MASK) ;
uint32_t cal = ADC0->CLP0
+ ADC0->CLP1
+ ADC0->CLP2
+ ADC0->CLP3
+ ADC0->CLP4
+ ADC0->CLPS;
ADC0->PG = 0x8000 | (cal >> 1);
}
void adc0_terminate()
{
SIM->SCGC6 &= ~SIM_SCGC6_ADC0(1);
}
uint16_t adc0_getRawSample(uint8_t ch)
{
if(ch > 32) return 0;
/* Conversion is automatically initiated by writing to this register */
ADC0->SC1[0] = ADC_SC1_ADCH(ch);
while(((ADC0->SC1[0]) & ADC_SC1_COCO_MASK) == 0) ;
return ADC0->R[0];
}
uint16_t adc0_getMeasurement(uint8_t ch)
{
/*
* ADC data width is 16 bit: to convert from ADC samples to voltage in mV,
* first multiply by 3300 and then divide the result by 65536 by right
* shifting it of 16 positions.
* With respect to using floats, maximum error is -1mV.
*/
uint32_t sample = adc0_getRawSample(ch) * 3300;
return ((uint16_t) (sample >> 16));
}