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targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/analogin_api.c
- Committer:
- mbed_official
- Date:
- 2016-01-15
- Revision:
- 50:a417edff4437
- Parent:
- 0:9b334a45a8ff
- Child:
- 144:ef7eb2e8f9f7
File content as of revision 50:a417edff4437:
/***************************************************************************//** * @file analogin_api.c ******************************************************************************* * @section License * <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b> ******************************************************************************* * * Permission is granted to anyone to use this software for any purpose, * including commercial applications, and to alter it and redistribute it * freely, subject to the following restrictions: * * 1. The origin of this software must not be misrepresented; you must not * claim that you wrote the original software. * 2. Altered source versions must be plainly marked as such, and must not be * misrepresented as being the original software. * 3. This notice may not be removed or altered from any source distribution. * * DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no * obligation to support this Software. Silicon Labs is providing the * Software "AS IS", with no express or implied warranties of any kind, * including, but not limited to, any implied warranties of merchantability * or fitness for any particular purpose or warranties against infringement * of any proprietary rights of a third party. * * Silicon Labs will not be liable for any consequential, incidental, or * special damages, or any other relief, or for any claim by any third party, * arising from your use of this Software. * ******************************************************************************/ #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