Lee Kai Xuan / mbed-os

mbed-os

Fork of mbed-os by erkin yucel

targets/TARGET_NXP/TARGET_LPC82X/analogin_api.c@0:f269e3021894, 2016-10-23 (annotated)

Committer:
elessair
Date:
Sun Oct 23 15:10:02 2016 +0000
Revision:
0:f269e3021894
Initial commit

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elessair 0:f269e3021894 1 /* mbed Microcontroller Library
elessair 0:f269e3021894 2 * Copyright (c) 2006-2013 ARM Limited
elessair 0:f269e3021894 3 *
elessair 0:f269e3021894 4 * Licensed under the Apache License, Version 2.0 (the "License");
elessair 0:f269e3021894 5 * you may not use this file except in compliance with the License.
elessair 0:f269e3021894 6 * You may obtain a copy of the License at
elessair 0:f269e3021894 7 *
elessair 0:f269e3021894 8 * http://www.apache.org/licenses/LICENSE-2.0
elessair 0:f269e3021894 9 *
elessair 0:f269e3021894 10 * Unless required by applicable law or agreed to in writing, software
elessair 0:f269e3021894 11 * distributed under the License is distributed on an "AS IS" BASIS,
elessair 0:f269e3021894 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
elessair 0:f269e3021894 13 * See the License for the specific language governing permissions and
elessair 0:f269e3021894 14 * limitations under the License.
elessair 0:f269e3021894 15 */
elessair 0:f269e3021894 16 #include "mbed_assert.h"
elessair 0:f269e3021894 17 #include "analogin_api.h"
elessair 0:f269e3021894 18 #include "cmsis.h"
elessair 0:f269e3021894 19 #include "pinmap.h"
elessair 0:f269e3021894 20 #include "PeripheralNames.h"
elessair 0:f269e3021894 21
elessair 0:f269e3021894 22 #if DEVICE_ANALOGIN
elessair 0:f269e3021894 23
elessair 0:f269e3021894 24 #define ANALOGIN_MEDIAN_FILTER 1
elessair 0:f269e3021894 25
elessair 0:f269e3021894 26 #define ADC_RANGE 0xFFF
elessair 0:f269e3021894 27
elessair 0:f269e3021894 28 static const PinMap PinMap_ADC[] = {
elessair 0:f269e3021894 29 {P0_7 , ADC_0, 0},
elessair 0:f269e3021894 30 {P0_6 , ADC_1, 0},
elessair 0:f269e3021894 31 {P0_14, ADC_2, 0},
elessair 0:f269e3021894 32 {P0_23, ADC_3, 0},
elessair 0:f269e3021894 33 {P0_22, ADC_4, 0},
elessair 0:f269e3021894 34 {P0_21, ADC_5, 0},
elessair 0:f269e3021894 35 {P0_20, ADC_6, 0},
elessair 0:f269e3021894 36 {P0_19, ADC_7, 0},
elessair 0:f269e3021894 37 {P0_18, ADC_8, 0},
elessair 0:f269e3021894 38 {P0_17, ADC_9, 0},
elessair 0:f269e3021894 39 {P0_13, ADC_10,0},
elessair 0:f269e3021894 40 {P0_4 , ADC_11,0},
elessair 0:f269e3021894 41 };
elessair 0:f269e3021894 42
elessair 0:f269e3021894 43 void analogin_init(analogin_t *obj, PinName pin)
elessair 0:f269e3021894 44 {
elessair 0:f269e3021894 45 obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
elessair 0:f269e3021894 46 MBED_ASSERT(obj->adc != (ADCName)NC);
elessair 0:f269e3021894 47
elessair 0:f269e3021894 48 LPC_SYSCON->SYSAHBCLKCTRL |= (1UL << 6);
elessair 0:f269e3021894 49 // pin enable
elessair 0:f269e3021894 50 LPC_SWM->PINENABLE0 &= ~(1UL << (13 + obj->adc));
elessair 0:f269e3021894 51 // configure GPIO as input
elessair 0:f269e3021894 52 LPC_GPIO_PORT->DIR0 &= ~(1UL << (pin >> PIN_SHIFT));
elessair 0:f269e3021894 53
elessair 0:f269e3021894 54 LPC_SYSCON->PDRUNCFG &= ~(1 << 4);
elessair 0:f269e3021894 55 LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 24);
elessair 0:f269e3021894 56
elessair 0:f269e3021894 57 __IO LPC_ADC_Type *adc_reg = LPC_ADC;
elessair 0:f269e3021894 58
elessair 0:f269e3021894 59 // determine the system clock divider for a 500kHz ADC clock during calibration
elessair 0:f269e3021894 60 uint32_t clkdiv = (SystemCoreClock / 500000) - 1;
elessair 0:f269e3021894 61
elessair 0:f269e3021894 62 // perform a self-calibration
elessair 0:f269e3021894 63 adc_reg->CTRL = (1UL << 30) | (clkdiv & 0xFF);
elessair 0:f269e3021894 64 while ((adc_reg->CTRL & (1UL << 30)) != 0);
elessair 0:f269e3021894 65 }
elessair 0:f269e3021894 66
elessair 0:f269e3021894 67 static inline uint32_t adc_read(analogin_t *obj)
elessair 0:f269e3021894 68 {
elessair 0:f269e3021894 69 uint32_t channels;
elessair 0:f269e3021894 70 __IO LPC_ADC_Type *adc_reg = LPC_ADC;
elessair 0:f269e3021894 71
elessair 0:f269e3021894 72 channels = (obj->adc & 0x1F);
elessair 0:f269e3021894 73
elessair 0:f269e3021894 74 // select channel
elessair 0:f269e3021894 75 adc_reg->SEQA_CTRL &= ~(0xFFF);
elessair 0:f269e3021894 76 adc_reg->SEQA_CTRL |= (1UL << channels);
elessair 0:f269e3021894 77
elessair 0:f269e3021894 78 // start conversion and sequence enable
elessair 0:f269e3021894 79 adc_reg->SEQA_CTRL |= ((1UL << 26) | (1UL << 31));
elessair 0:f269e3021894 80
elessair 0:f269e3021894 81 // Repeatedly get the sample data until DONE bit
elessair 0:f269e3021894 82 volatile uint32_t data;
elessair 0:f269e3021894 83 do {
elessair 0:f269e3021894 84 data = adc_reg->SEQA_GDAT;
elessair 0:f269e3021894 85 } while ((data & (1UL << 31)) == 0);
elessair 0:f269e3021894 86
elessair 0:f269e3021894 87 // Stop conversion
elessair 0:f269e3021894 88 adc_reg->SEQA_CTRL &= ~(1UL << 31);
elessair 0:f269e3021894 89
elessair 0:f269e3021894 90 return ((data >> 4) & ADC_RANGE);
elessair 0:f269e3021894 91 }
elessair 0:f269e3021894 92
elessair 0:f269e3021894 93 static inline void order(uint32_t *a, uint32_t *b)
elessair 0:f269e3021894 94 {
elessair 0:f269e3021894 95 if (*a > *b) {
elessair 0:f269e3021894 96 uint32_t t = *a;
elessair 0:f269e3021894 97 *a = *b;
elessair 0:f269e3021894 98 *b = t;
elessair 0:f269e3021894 99 }
elessair 0:f269e3021894 100 }
elessair 0:f269e3021894 101
elessair 0:f269e3021894 102 static inline uint32_t adc_read_u32(analogin_t *obj)
elessair 0:f269e3021894 103 {
elessair 0:f269e3021894 104 uint32_t value;
elessair 0:f269e3021894 105 #if ANALOGIN_MEDIAN_FILTER
elessair 0:f269e3021894 106 uint32_t v1 = adc_read(obj);
elessair 0:f269e3021894 107 uint32_t v2 = adc_read(obj);
elessair 0:f269e3021894 108 uint32_t v3 = adc_read(obj);
elessair 0:f269e3021894 109 order(&v1, &v2);
elessair 0:f269e3021894 110 order(&v2, &v3);
elessair 0:f269e3021894 111 order(&v1, &v2);
elessair 0:f269e3021894 112 value = v2;
elessair 0:f269e3021894 113 #else
elessair 0:f269e3021894 114 value = adc_read(obj);
elessair 0:f269e3021894 115 #endif
elessair 0:f269e3021894 116 return value;
elessair 0:f269e3021894 117 }
elessair 0:f269e3021894 118
elessair 0:f269e3021894 119 uint16_t analogin_read_u16(analogin_t *obj)
elessair 0:f269e3021894 120 {
elessair 0:f269e3021894 121 uint32_t value = adc_read_u32(obj);
elessair 0:f269e3021894 122 return (value << 4) | ((value >> 8) & 0x000F); // 12 bit
elessair 0:f269e3021894 123 }
elessair 0:f269e3021894 124
elessair 0:f269e3021894 125 float analogin_read(analogin_t *obj)
elessair 0:f269e3021894 126 {
elessair 0:f269e3021894 127 uint32_t value = adc_read_u32(obj);
elessair 0:f269e3021894 128 return (float)value * (1.0f / (float)ADC_RANGE);
elessair 0:f269e3021894 129 }
elessair 0:f269e3021894 130
elessair 0:f269e3021894 131 #endif