Johannes Stratmann / mbed-dev

added prescaler for 16 bit pwm in LPC1347 target

Fork of mbed-dev by mbed official

targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/analogin_api.c@147:ba84b7dc41a7, 2016-09-10 (annotated)

Committer:
JojoS
Date:
Sat Sep 10 15:32:04 2016 +0000
Revision:
147:ba84b7dc41a7
Parent:
144:ef7eb2e8f9f7 
added prescaler for 16 bit timers (solution as in LPC11xx), default prescaler 31 for max 28 ms period time

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);
<> 144:ef7eb2e8f9f7 43 MBED_ASSERT((int) obj->adc != NC);
<> 144:ef7eb2e8f9f7 44
<> 144:ef7eb2e8f9f7 45 obj->channel = pin_location(pin, PinMap_ADC);
<> 144:ef7eb2e8f9f7 46 MBED_ASSERT((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 {
<> 144:ef7eb2e8f9f7 102 /* Convert from a uint16 to a float between 0 and 1 by division by 0xFFFF */
<> 144:ef7eb2e8f9f7 103 return analogin_read_u16(obj) / (float) 0xFFFF;
<> 144:ef7eb2e8f9f7 104 }
<> 144:ef7eb2e8f9f7 105
<> 144:ef7eb2e8f9f7 106 #endif