mirror of https://github.com/ARMmbed/mbed-os.git
107 lines
3.3 KiB
C
107 lines
3.3 KiB
C
/***************************************************************************//**
|
|
* @file analogin_api.c
|
|
*******************************************************************************
|
|
* @section License
|
|
* <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b>
|
|
*******************************************************************************
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*
|
|
* 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 "device.h"
|
|
#if DEVICE_ANALOGIN
|
|
|
|
#include "mbed_assert.h"
|
|
#include "analogin_api.h"
|
|
|
|
#include "pinmap.h"
|
|
#include "pinmap_function.h"
|
|
#include "PeripheralPins.h"
|
|
|
|
#include "em_adc.h"
|
|
#include "em_cmu.h"
|
|
|
|
void analogin_init(analogin_t *obj, PinName pin)
|
|
{
|
|
static uint8_t adc_initialized = 0;
|
|
|
|
/* Init structure */
|
|
obj->adc = (ADC_TypeDef *) pinmap_peripheral(pin, PinMap_ADC);
|
|
MBED_ASSERT((unsigned int) obj->adc != NC);
|
|
|
|
obj->channel = pin_location(pin, PinMap_ADC);
|
|
MBED_ASSERT((unsigned int) obj->channel != NC);
|
|
|
|
/* Only initialize the ADC once */
|
|
if (!adc_initialized) {
|
|
/* Turn on the clock */
|
|
CMU_ClockEnable(cmuClock_ADC0, true);
|
|
|
|
/* Init with default settings */
|
|
ADC_Init_TypeDef init = ADC_INIT_DEFAULT;
|
|
init.prescale = 4;
|
|
ADC_Init(obj->adc, &init);
|
|
|
|
/* Init for single conversion use */
|
|
ADC_InitSingle_TypeDef singleInit = ADC_INITSINGLE_DEFAULT;
|
|
|
|
/* Measure input channel with Vdd reference. */
|
|
singleInit.reference = adcRefVDD;
|
|
singleInit.resolution = adcRes12Bit;
|
|
singleInit.acqTime = adcAcqTime32;
|
|
|
|
ADC_InitSingle(obj->adc, &singleInit);
|
|
|
|
adc_initialized = 1;
|
|
}
|
|
}
|
|
|
|
uint16_t analogin_read_u16(analogin_t *obj)
|
|
{
|
|
ADC_TypeDef *adc = obj->adc;
|
|
uint16_t sample = 0;
|
|
|
|
//Make sure a single conversion is not in progress
|
|
adc->CMD = ADC_CMD_SINGLESTOP;
|
|
|
|
// Make sure we are checking the correct channel
|
|
#if defined _ADC_SINGLECTRL_INPUTSEL_MASK
|
|
adc->SINGLECTRL = (adc->SINGLECTRL & ~_ADC_SINGLECTRL_INPUTSEL_MASK) | obj->channel;
|
|
#elif _ADC_SINGLECTRL_POSSEL_MASK
|
|
adc->SINGLECTRL = (adc->SINGLECTRL & ~_ADC_SINGLECTRL_POSSEL_MASK) | obj->channel << _ADC_SINGLECTRL_POSSEL_SHIFT;
|
|
#endif
|
|
|
|
ADC_Start(adc, adcStartSingle);
|
|
|
|
/* Wait while conversion is active */
|
|
while (adc->STATUS & ADC_STATUS_SINGLEACT);
|
|
|
|
/* Get ADC result */
|
|
sample = ADC_DataSingleGet(adc);
|
|
|
|
/* The ADC has 12 bit resolution. We shift in 4 0s */
|
|
/* from the right to make it a 16 bit number as expected */
|
|
return sample << 4;
|
|
}
|
|
|
|
float analogin_read(analogin_t *obj)
|
|
{
|
|
/* Convert from a uint16 to a float between 0 and 1 by division by 0xFFF0 */
|
|
return analogin_read_u16(obj) / (float) 0xFFF0;
|
|
}
|
|
|
|
#endif
|