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Diff: targets/TARGET_NORDIC/TARGET_MCU_NRF51822/analogin_api.c
- Revision:
- 149:156823d33999
- Parent:
- 144:ef7eb2e8f9f7
- Child:
- 151:5eaa88a5bcc7
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/TARGET_NORDIC/TARGET_MCU_NRF51822/analogin_api.c Fri Oct 28 11:17:30 2016 +0100 @@ -0,0 +1,81 @@ +/* mbed Microcontroller Library + * Copyright (c) 2006-2013 ARM Limited + * + * 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 "mbed_assert.h" +#include "analogin_api.h" +#include "cmsis.h" +#include "pinmap.h" + +#define ANALOGIN_MEDIAN_FILTER 1 +#define ADC_10BIT_RANGE 0x3FF +#define ADC_RANGE ADC_10BIT_RANGE + +static const PinMap PinMap_ADC[] = { + {p1, ADC0_0, 4}, + {p2, ADC0_0, 8}, + {p3, ADC0_0, 16}, + {p4, ADC0_0, 32}, + {p5, ADC0_0, 64}, + {p6, ADC0_0, 128}, +#ifndef TARGET_NRF51_DONGLE + {p26, ADC0_0, 1}, + {p27, ADC0_0, 2}, +#endif + {NC, NC, 0} +}; + +void analogin_init(analogin_t *obj, PinName pin) +{ + int analogInputPin = 0; + const PinMap *map = PinMap_ADC; + + obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC); //(NRF_ADC_Type *) + MBED_ASSERT(obj->adc != (ADCName)NC); + + while (map->pin != NC) { + if (map->pin == pin) { + analogInputPin = map->function; + break; + } + map++; + } + obj->adc_pin = (uint8_t)analogInputPin; + + NRF_ADC->ENABLE = ADC_ENABLE_ENABLE_Enabled; + NRF_ADC->CONFIG = (ADC_CONFIG_RES_10bit << ADC_CONFIG_RES_Pos) | + (ADC_CONFIG_INPSEL_AnalogInputOneThirdPrescaling << ADC_CONFIG_INPSEL_Pos) | + (ADC_CONFIG_REFSEL_SupplyOneThirdPrescaling << ADC_CONFIG_REFSEL_Pos) | + (analogInputPin << ADC_CONFIG_PSEL_Pos) | + (ADC_CONFIG_EXTREFSEL_None << ADC_CONFIG_EXTREFSEL_Pos); +} + +uint16_t analogin_read_u16(analogin_t *obj) +{ + NRF_ADC->CONFIG &= ~ADC_CONFIG_PSEL_Msk; + NRF_ADC->CONFIG |= obj->adc_pin << ADC_CONFIG_PSEL_Pos; + NRF_ADC->EVENTS_END = 0; + NRF_ADC->TASKS_START = 1; + + while (!NRF_ADC->EVENTS_END) { + } + + return (uint16_t)NRF_ADC->RESULT; // 10 bit +} + +float analogin_read(analogin_t *obj) +{ + uint16_t value = analogin_read_u16(obj); + return (float)value * (1.0f / (float)ADC_RANGE); +}