t
Fork of mbed-dev by
targets/TARGET_Silicon_Labs/TARGET_EFM32/analogin_api.c
- Committer:
- amithy
- Date:
- 2017-11-09
- Revision:
- 178:c26431f84b0d
- Parent:
- 149:156823d33999
- Child:
- 176:447f873cad2f
File content as of revision 178:c26431f84b0d:
/***************************************************************************//** * @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((int) obj->adc != NC); obj->channel = pin_location(pin, PinMap_ADC); MBED_ASSERT((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 0xFFFF */ return analogin_read_u16(obj) / (float) 0xFFFF; } #endif