mirror of https://github.com/ARMmbed/mbed-os.git
143 lines
3.7 KiB
C
143 lines
3.7 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2006-2013 ARM Limited
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "mbed_assert.h"
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#include "analogin_api.h"
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#include "cmsis.h"
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#include "pinmap.h"
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#include "mbed_error.h"
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#if DEVICE_ANALOGIN
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#define ANALOGIN_MEDIAN_FILTER 1
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#define ADC_10BIT_RANGE 0x3FF
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#define ADC_12BIT_RANGE 0xFFF
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#define PDRUN_VALID_BITS 0x000025FFL
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#define PDRUN_RESERVED_ONE 0x0000C800L
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#define ADC_RANGE ADC_12BIT_RANGE
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static const PinMap PinMap_ADC[] = {
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{P1_9 , ADC_0, 3},
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{P0_23, ADC_1, 1},
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{P0_16, ADC_2, 1},
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{P0_15, ADC_3, 3},
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{P1_22, ADC_4, 3},
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{P1_3 , ADC_5, 4},
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{P0_14, ADC_6, 2},
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{P0_13, ADC_7, 2},
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{P0_12, ADC_8, 2},
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{P0_11, ADC_9, 2},
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{P1_29, ADC_10,4},
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{P0_22, ADC_11,1},
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{NC , NC ,0}
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};
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void analogin_init(analogin_t *obj, PinName pin) {
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volatile uint32_t tmp;
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obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
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MBED_ASSERT(obj->adc != (ADCName)NC);
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pinmap_pinout(pin, PinMap_ADC);
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__IO uint32_t *reg = (__IO uint32_t*)(LPC_IOCON_BASE + (pin & 0x1FF));
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// set pin to ADC mode
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*reg &= ~(1 << 7); // set ADMODE = 0 (analog mode)
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// ADC Powered
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tmp = (LPC_SYSCON->PDRUNCFG & PDRUN_VALID_BITS);
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tmp &= ~((1 << 4) & PDRUN_VALID_BITS);
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LPC_SYSCON->PDRUNCFG = (tmp | PDRUN_RESERVED_ONE);
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// Enable clock for ADC
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LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 13);
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// Determine the clock divider for a 500kHz ADC clock during calibration
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uint32_t clkdiv = (SystemCoreClock / 500000) - 1;
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// Perform a self-calibration
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LPC_ADC->CTRL = (1UL << 30) | (clkdiv & 0xFF);
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while ((LPC_ADC->CTRL & (1UL << 30)) != 0);
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// Sampling clock: SystemClock divided by 1
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LPC_ADC->CTRL = 0;
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}
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static inline uint32_t adc_read(analogin_t *obj) {
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// select channel
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LPC_ADC->SEQA_CTRL &= ~(0xFFF);
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LPC_ADC->SEQA_CTRL |= (1UL << obj->adc);
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// start conversion, sequence enable with async mode
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LPC_ADC->SEQA_CTRL |= ((1UL << 26) | (1UL << 31) | (1UL << 19));
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// Repeatedly get the sample data until DONE bit
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volatile uint32_t data;
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do {
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data = LPC_ADC->SEQA_GDAT;
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} while ((data & (1UL << 31)) == 0);
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data = LPC_ADC->DAT[obj->adc];
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// Stop conversion
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LPC_ADC->SEQA_CTRL &= ~(1UL << 31);
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return ((data >> 4) & ADC_RANGE);
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}
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static inline void order(uint32_t *a, uint32_t *b) {
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if (*a > *b) {
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uint32_t t = *a;
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*a = *b;
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*b = t;
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}
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}
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static inline uint32_t adc_read_u32(analogin_t *obj) {
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uint32_t value;
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#if ANALOGIN_MEDIAN_FILTER
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uint32_t v1 = adc_read(obj);
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uint32_t v2 = adc_read(obj);
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uint32_t v3 = adc_read(obj);
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order(&v1, &v2);
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order(&v2, &v3);
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order(&v1, &v2);
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value = v2;
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#else
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value = adc_read(obj);
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#endif
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return value;
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}
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uint16_t analogin_read_u16(analogin_t *obj) {
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uint32_t value = adc_read_u32(obj);
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return (value << 4) | ((value >> 8) & 0x000F); // 12 bit
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}
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float analogin_read(analogin_t *obj) {
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uint32_t value = adc_read_u32(obj);
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return (float)value * (1.0f / (float)ADC_RANGE);
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}
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const PinMap *analogin_pinmap()
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{
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return PinMap_ADC;
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}
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#endif
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