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/* mbed Microcontroller Library
* Copyright (c) 2006-2013 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "mbed_assert.h"
#include "analogin_api.h"
#include "cmsis.h"
#include "pinmap.h"
#define ANALOGIN_MEDIAN_FILTER 1
#define ADC_10BIT_RANGE 0x3FF
#define ADC_RANGE ADC_10BIT_RANGE
static const PinMap PinMap_ADC[] = {
{p1, ADC0_0, 4},
{p2, ADC0_0, 8},
{p3, ADC0_0, 16},
{p4, ADC0_0, 32},
{p5, ADC0_0, 64},
{p6, ADC0_0, 128},
{NC, NC, 0}
};
void analogin_init(analogin_t *obj, PinName pin)
{
int analogInputPin = 0;
const PinMap *map = PinMap_ADC;
obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC); //(NRF_ADC_Type *)
MBED_ASSERT(obj->adc != (ADCName)NC);
while (map->pin != NC) {
if (map->pin == pin) {
analogInputPin = map->function;
break;
}
map++;
}
obj->adc_pin = (uint8_t)analogInputPin;
NRF_ADC->ENABLE = ADC_ENABLE_ENABLE_Enabled;
NRF_ADC->CONFIG = (ADC_CONFIG_RES_10bit << ADC_CONFIG_RES_Pos) |
(ADC_CONFIG_INPSEL_AnalogInputOneThirdPrescaling << ADC_CONFIG_INPSEL_Pos) |
(ADC_CONFIG_REFSEL_SupplyOneThirdPrescaling << ADC_CONFIG_REFSEL_Pos) |
(analogInputPin << ADC_CONFIG_PSEL_Pos) |
(ADC_CONFIG_EXTREFSEL_None << ADC_CONFIG_EXTREFSEL_Pos);
}
uint16_t analogin_read_u16(analogin_t *obj)
{
NRF_ADC->CONFIG &= ~ADC_CONFIG_PSEL_Msk;
NRF_ADC->CONFIG |= obj->adc_pin << ADC_CONFIG_PSEL_Pos;
NRF_ADC->TASKS_START = 1;
while (((NRF_ADC->BUSY & ADC_BUSY_BUSY_Msk) >> ADC_BUSY_BUSY_Pos) == ADC_BUSY_BUSY_Busy) {
}
return (uint16_t)NRF_ADC->RESULT; // 10 bit
}
float analogin_read(analogin_t *obj)
{
uint16_t value = analogin_read_u16(obj);
return (float)value * (1.0f / (float)ADC_RANGE);
}