mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

Dependents:   Nucleo_Hello_Encoder BLE_iBeaconScan AM1805_DEMO DISCO-F429ZI_ExportTemplate1 ... more

targets/TARGET_Silicon_Labs/TARGET_EFM32/analogin_api.c@189:f392fc9709a3, 2019-02-20 (annotated)

Committer:
AnnaBridge
Date:
Wed Feb 20 22:31:08 2019 +0000
Revision:
189:f392fc9709a3
Parent:
179:b0033dcd6934 
mbed library release version 165

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 144:ef7eb2e8f9f7 1 /***************************************************************************//**
<> 144:ef7eb2e8f9f7 2 * @file analogin_api.c
<> 144:ef7eb2e8f9f7 3 *******************************************************************************
<> 144:ef7eb2e8f9f7 4 * @section License
<> 144:ef7eb2e8f9f7 5 * <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b>
<> 144:ef7eb2e8f9f7 6 *******************************************************************************
<> 144:ef7eb2e8f9f7 7 *
<> 144:ef7eb2e8f9f7 8 * SPDX-License-Identifier: Apache-2.0
<> 144:ef7eb2e8f9f7 9 *
<> 144:ef7eb2e8f9f7 10 * Licensed under the Apache License, Version 2.0 (the "License"); you may
<> 144:ef7eb2e8f9f7 11 * not use this file except in compliance with the License.
<> 144:ef7eb2e8f9f7 12 * You may obtain a copy of the License at
<> 144:ef7eb2e8f9f7 13 *
<> 144:ef7eb2e8f9f7 14 * http://www.apache.org/licenses/LICENSE-2.0
<> 144:ef7eb2e8f9f7 15 *
<> 144:ef7eb2e8f9f7 16 * Unless required by applicable law or agreed to in writing, software
<> 144:ef7eb2e8f9f7 17 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
<> 144:ef7eb2e8f9f7 18 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 144:ef7eb2e8f9f7 19 * See the License for the specific language governing permissions and
<> 144:ef7eb2e8f9f7 20 * limitations under the License.
<> 144:ef7eb2e8f9f7 21 *
<> 144:ef7eb2e8f9f7 22 ******************************************************************************/
<> 144:ef7eb2e8f9f7 23
<> 144:ef7eb2e8f9f7 24 #include "device.h"
<> 144:ef7eb2e8f9f7 25 #if DEVICE_ANALOGIN
<> 144:ef7eb2e8f9f7 26
<> 144:ef7eb2e8f9f7 27 #include "mbed_assert.h"
<> 144:ef7eb2e8f9f7 28 #include "analogin_api.h"
<> 144:ef7eb2e8f9f7 29
<> 144:ef7eb2e8f9f7 30 #include "pinmap.h"
<> 144:ef7eb2e8f9f7 31 #include "pinmap_function.h"
<> 144:ef7eb2e8f9f7 32 #include "PeripheralPins.h"
<> 144:ef7eb2e8f9f7 33
<> 144:ef7eb2e8f9f7 34 #include "em_adc.h"
<> 144:ef7eb2e8f9f7 35 #include "em_cmu.h"
<> 144:ef7eb2e8f9f7 36
<> 144:ef7eb2e8f9f7 37 void analogin_init(analogin_t *obj, PinName pin)
<> 144:ef7eb2e8f9f7 38 {
<> 144:ef7eb2e8f9f7 39 static uint8_t adc_initialized = 0;
<> 144:ef7eb2e8f9f7 40
<> 144:ef7eb2e8f9f7 41 /* Init structure */
<> 144:ef7eb2e8f9f7 42 obj->adc = (ADC_TypeDef *) pinmap_peripheral(pin, PinMap_ADC);
AnnaBridge 179:b0033dcd6934 43 MBED_ASSERT((unsigned int) obj->adc != NC);
<> 144:ef7eb2e8f9f7 44
<> 144:ef7eb2e8f9f7 45 obj->channel = pin_location(pin, PinMap_ADC);
AnnaBridge 179:b0033dcd6934 46 MBED_ASSERT((unsigned int) obj->channel != NC);
<> 144:ef7eb2e8f9f7 47
<> 144:ef7eb2e8f9f7 48 /* Only initialize the ADC once */
<> 144:ef7eb2e8f9f7 49 if (!adc_initialized) {
<> 144:ef7eb2e8f9f7 50 /* Turn on the clock */
<> 144:ef7eb2e8f9f7 51 CMU_ClockEnable(cmuClock_ADC0, true);
<> 144:ef7eb2e8f9f7 52
<> 144:ef7eb2e8f9f7 53 /* Init with default settings */
<> 144:ef7eb2e8f9f7 54 ADC_Init_TypeDef init = ADC_INIT_DEFAULT;
<> 144:ef7eb2e8f9f7 55 init.prescale = 4;
<> 144:ef7eb2e8f9f7 56 ADC_Init(obj->adc, &init);
<> 144:ef7eb2e8f9f7 57
<> 144:ef7eb2e8f9f7 58 /* Init for single conversion use */
<> 144:ef7eb2e8f9f7 59 ADC_InitSingle_TypeDef singleInit = ADC_INITSINGLE_DEFAULT;
<> 144:ef7eb2e8f9f7 60
<> 144:ef7eb2e8f9f7 61 /* Measure input channel with Vdd reference. */
<> 144:ef7eb2e8f9f7 62 singleInit.reference = adcRefVDD;
<> 144:ef7eb2e8f9f7 63 singleInit.resolution = adcRes12Bit;
<> 144:ef7eb2e8f9f7 64 singleInit.acqTime = adcAcqTime32;
<> 144:ef7eb2e8f9f7 65
<> 144:ef7eb2e8f9f7 66 ADC_InitSingle(obj->adc, &singleInit);
<> 144:ef7eb2e8f9f7 67
<> 144:ef7eb2e8f9f7 68 adc_initialized = 1;
<> 144:ef7eb2e8f9f7 69 }
<> 144:ef7eb2e8f9f7 70 }
<> 144:ef7eb2e8f9f7 71
<> 144:ef7eb2e8f9f7 72 uint16_t analogin_read_u16(analogin_t *obj)
<> 144:ef7eb2e8f9f7 73 {
<> 144:ef7eb2e8f9f7 74 ADC_TypeDef *adc = obj->adc;
<> 144:ef7eb2e8f9f7 75 uint16_t sample = 0;
<> 144:ef7eb2e8f9f7 76
<> 144:ef7eb2e8f9f7 77 //Make sure a single conversion is not in progress
<> 144:ef7eb2e8f9f7 78 adc->CMD = ADC_CMD_SINGLESTOP;
<> 144:ef7eb2e8f9f7 79
<> 144:ef7eb2e8f9f7 80 // Make sure we are checking the correct channel
<> 144:ef7eb2e8f9f7 81 #if defined _ADC_SINGLECTRL_INPUTSEL_MASK
<> 144:ef7eb2e8f9f7 82 adc->SINGLECTRL = (adc->SINGLECTRL & ~_ADC_SINGLECTRL_INPUTSEL_MASK) | obj->channel;
<> 144:ef7eb2e8f9f7 83 #elif _ADC_SINGLECTRL_POSSEL_MASK
<> 144:ef7eb2e8f9f7 84 adc->SINGLECTRL = (adc->SINGLECTRL & ~_ADC_SINGLECTRL_POSSEL_MASK) | obj->channel << _ADC_SINGLECTRL_POSSEL_SHIFT;
<> 144:ef7eb2e8f9f7 85 #endif
<> 144:ef7eb2e8f9f7 86
<> 144:ef7eb2e8f9f7 87 ADC_Start(adc, adcStartSingle);
<> 144:ef7eb2e8f9f7 88
<> 144:ef7eb2e8f9f7 89 /* Wait while conversion is active */
<> 144:ef7eb2e8f9f7 90 while (adc->STATUS & ADC_STATUS_SINGLEACT);
<> 144:ef7eb2e8f9f7 91
<> 144:ef7eb2e8f9f7 92 /* Get ADC result */
<> 144:ef7eb2e8f9f7 93 sample = ADC_DataSingleGet(adc);
<> 144:ef7eb2e8f9f7 94
<> 144:ef7eb2e8f9f7 95 /* The ADC has 12 bit resolution. We shift in 4 0s */
<> 144:ef7eb2e8f9f7 96 /* from the right to make it a 16 bit number as expected */
<> 144:ef7eb2e8f9f7 97 return sample << 4;
<> 144:ef7eb2e8f9f7 98 }
<> 144:ef7eb2e8f9f7 99
<> 144:ef7eb2e8f9f7 100 float analogin_read(analogin_t *obj)
<> 144:ef7eb2e8f9f7 101 {
AnnaBridge 176:447f873cad2f 102 /* Convert from a uint16 to a float between 0 and 1 by division by 0xFFF0 */
AnnaBridge 176:447f873cad2f 103 return analogin_read_u16(obj) / (float) 0xFFF0;
<> 144:ef7eb2e8f9f7 104 }
<> 144:ef7eb2e8f9f7 105
<> 144:ef7eb2e8f9f7 106 #endif