teralytic / mbed-dev

mbed library sources. Supersedes mbed-src.

Fork of mbed by teralytic

targets/hal/TARGET_NXP/TARGET_LPC82X/analogin_api.c@0:9b334a45a8ff, 2015-10-01 (annotated)

Committer:
bogdanm
Date:
Thu Oct 01 15:25:22 2015 +0300
Revision:
0:9b334a45a8ff
Child:
144:ef7eb2e8f9f7
Initial commit on mbed-dev



Replaces mbed-src (now inactive)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 0:9b334a45a8ff 1 /* mbed Microcontroller Library
bogdanm 0:9b334a45a8ff 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 0:9b334a45a8ff 3 *
bogdanm 0:9b334a45a8ff 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 0:9b334a45a8ff 5 * you may not use this file except in compliance with the License.
bogdanm 0:9b334a45a8ff 6 * You may obtain a copy of the License at
bogdanm 0:9b334a45a8ff 7 *
bogdanm 0:9b334a45a8ff 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 0:9b334a45a8ff 9 *
bogdanm 0:9b334a45a8ff 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 0:9b334a45a8ff 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 0:9b334a45a8ff 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 0:9b334a45a8ff 13 * See the License for the specific language governing permissions and
bogdanm 0:9b334a45a8ff 14 * limitations under the License.
bogdanm 0:9b334a45a8ff 15 */
bogdanm 0:9b334a45a8ff 16 #include "mbed_assert.h"
bogdanm 0:9b334a45a8ff 17 #include "analogin_api.h"
bogdanm 0:9b334a45a8ff 18 #include "cmsis.h"
bogdanm 0:9b334a45a8ff 19 #include "pinmap.h"
bogdanm 0:9b334a45a8ff 20 #include "PeripheralNames.h"
bogdanm 0:9b334a45a8ff 21
bogdanm 0:9b334a45a8ff 22 #if DEVICE_ANALOGIN
bogdanm 0:9b334a45a8ff 23
bogdanm 0:9b334a45a8ff 24 #define ANALOGIN_MEDIAN_FILTER 1
bogdanm 0:9b334a45a8ff 25
bogdanm 0:9b334a45a8ff 26 #define ADC_RANGE 0xFFF
bogdanm 0:9b334a45a8ff 27
bogdanm 0:9b334a45a8ff 28 static const PinMap PinMap_ADC[] = {
bogdanm 0:9b334a45a8ff 29 {P0_7 , ADC_0, 0},
bogdanm 0:9b334a45a8ff 30 {P0_6 , ADC_1, 0},
bogdanm 0:9b334a45a8ff 31 {P0_14, ADC_2, 0},
bogdanm 0:9b334a45a8ff 32 {P0_23, ADC_3, 0},
bogdanm 0:9b334a45a8ff 33 {P0_22, ADC_4, 0},
bogdanm 0:9b334a45a8ff 34 {P0_21, ADC_5, 0},
bogdanm 0:9b334a45a8ff 35 {P0_20, ADC_6, 0},
bogdanm 0:9b334a45a8ff 36 {P0_19, ADC_7, 0},
bogdanm 0:9b334a45a8ff 37 {P0_18, ADC_8, 0},
bogdanm 0:9b334a45a8ff 38 {P0_17, ADC_9, 0},
bogdanm 0:9b334a45a8ff 39 {P0_13, ADC_10,0},
bogdanm 0:9b334a45a8ff 40 {P0_4 , ADC_11,0},
bogdanm 0:9b334a45a8ff 41 };
bogdanm 0:9b334a45a8ff 42
bogdanm 0:9b334a45a8ff 43 void analogin_init(analogin_t *obj, PinName pin)
bogdanm 0:9b334a45a8ff 44 {
bogdanm 0:9b334a45a8ff 45 obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
bogdanm 0:9b334a45a8ff 46 MBED_ASSERT(obj->adc != (ADCName)NC);
bogdanm 0:9b334a45a8ff 47
bogdanm 0:9b334a45a8ff 48 LPC_SYSCON->SYSAHBCLKCTRL |= (1UL << 6);
bogdanm 0:9b334a45a8ff 49 // pin enable
bogdanm 0:9b334a45a8ff 50 LPC_SWM->PINENABLE0 &= ~(1UL << (13 + obj->adc));
bogdanm 0:9b334a45a8ff 51 // configure GPIO as input
bogdanm 0:9b334a45a8ff 52 LPC_GPIO_PORT->DIR0 &= ~(1UL << (pin >> PIN_SHIFT));
bogdanm 0:9b334a45a8ff 53
bogdanm 0:9b334a45a8ff 54 LPC_SYSCON->PDRUNCFG &= ~(1 << 4);
bogdanm 0:9b334a45a8ff 55 LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 24);
bogdanm 0:9b334a45a8ff 56
bogdanm 0:9b334a45a8ff 57 __IO LPC_ADC_Type *adc_reg = LPC_ADC;
bogdanm 0:9b334a45a8ff 58
bogdanm 0:9b334a45a8ff 59 // determine the system clock divider for a 500kHz ADC clock during calibration
bogdanm 0:9b334a45a8ff 60 uint32_t clkdiv = (SystemCoreClock / 500000) - 1;
bogdanm 0:9b334a45a8ff 61
bogdanm 0:9b334a45a8ff 62 // perform a self-calibration
bogdanm 0:9b334a45a8ff 63 adc_reg->CTRL = (1UL << 30) | (clkdiv & 0xFF);
bogdanm 0:9b334a45a8ff 64 while ((adc_reg->CTRL & (1UL << 30)) != 0);
bogdanm 0:9b334a45a8ff 65 }
bogdanm 0:9b334a45a8ff 66
bogdanm 0:9b334a45a8ff 67 static inline uint32_t adc_read(analogin_t *obj)
bogdanm 0:9b334a45a8ff 68 {
bogdanm 0:9b334a45a8ff 69 uint32_t channels;
bogdanm 0:9b334a45a8ff 70 __IO LPC_ADC_Type *adc_reg = LPC_ADC;
bogdanm 0:9b334a45a8ff 71
bogdanm 0:9b334a45a8ff 72 channels = (obj->adc & 0x1F);
bogdanm 0:9b334a45a8ff 73
bogdanm 0:9b334a45a8ff 74 // select channel
bogdanm 0:9b334a45a8ff 75 adc_reg->SEQA_CTRL &= ~(0xFFF);
bogdanm 0:9b334a45a8ff 76 adc_reg->SEQA_CTRL |= (1UL << channels);
bogdanm 0:9b334a45a8ff 77
bogdanm 0:9b334a45a8ff 78 // start conversion and sequence enable
bogdanm 0:9b334a45a8ff 79 adc_reg->SEQA_CTRL |= ((1UL << 26) | (1UL << 31));
bogdanm 0:9b334a45a8ff 80
bogdanm 0:9b334a45a8ff 81 // Repeatedly get the sample data until DONE bit
bogdanm 0:9b334a45a8ff 82 volatile uint32_t data;
bogdanm 0:9b334a45a8ff 83 do {
bogdanm 0:9b334a45a8ff 84 data = adc_reg->SEQA_GDAT;
bogdanm 0:9b334a45a8ff 85 } while ((data & (1UL << 31)) == 0);
bogdanm 0:9b334a45a8ff 86
bogdanm 0:9b334a45a8ff 87 // Stop conversion
bogdanm 0:9b334a45a8ff 88 adc_reg->SEQA_CTRL &= ~(1UL << 31);
bogdanm 0:9b334a45a8ff 89
bogdanm 0:9b334a45a8ff 90 return ((data >> 4) & ADC_RANGE);
bogdanm 0:9b334a45a8ff 91 }
bogdanm 0:9b334a45a8ff 92
bogdanm 0:9b334a45a8ff 93 static inline void order(uint32_t *a, uint32_t *b)
bogdanm 0:9b334a45a8ff 94 {
bogdanm 0:9b334a45a8ff 95 if (*a > *b) {
bogdanm 0:9b334a45a8ff 96 uint32_t t = *a;
bogdanm 0:9b334a45a8ff 97 *a = *b;
bogdanm 0:9b334a45a8ff 98 *b = t;
bogdanm 0:9b334a45a8ff 99 }
bogdanm 0:9b334a45a8ff 100 }
bogdanm 0:9b334a45a8ff 101
bogdanm 0:9b334a45a8ff 102 static inline uint32_t adc_read_u32(analogin_t *obj)
bogdanm 0:9b334a45a8ff 103 {
bogdanm 0:9b334a45a8ff 104 uint32_t value;
bogdanm 0:9b334a45a8ff 105 #if ANALOGIN_MEDIAN_FILTER
bogdanm 0:9b334a45a8ff 106 uint32_t v1 = adc_read(obj);
bogdanm 0:9b334a45a8ff 107 uint32_t v2 = adc_read(obj);
bogdanm 0:9b334a45a8ff 108 uint32_t v3 = adc_read(obj);
bogdanm 0:9b334a45a8ff 109 order(&v1, &v2);
bogdanm 0:9b334a45a8ff 110 order(&v2, &v3);
bogdanm 0:9b334a45a8ff 111 order(&v1, &v2);
bogdanm 0:9b334a45a8ff 112 value = v2;
bogdanm 0:9b334a45a8ff 113 #else
bogdanm 0:9b334a45a8ff 114 value = adc_read(obj);
bogdanm 0:9b334a45a8ff 115 #endif
bogdanm 0:9b334a45a8ff 116 return value;
bogdanm 0:9b334a45a8ff 117 }
bogdanm 0:9b334a45a8ff 118
bogdanm 0:9b334a45a8ff 119 uint16_t analogin_read_u16(analogin_t *obj)
bogdanm 0:9b334a45a8ff 120 {
bogdanm 0:9b334a45a8ff 121 uint32_t value = adc_read_u32(obj);
bogdanm 0:9b334a45a8ff 122 return (value << 4) | ((value >> 8) & 0x000F); // 12 bit
bogdanm 0:9b334a45a8ff 123 }
bogdanm 0:9b334a45a8ff 124
bogdanm 0:9b334a45a8ff 125 float analogin_read(analogin_t *obj)
bogdanm 0:9b334a45a8ff 126 {
bogdanm 0:9b334a45a8ff 127 uint32_t value = adc_read_u32(obj);
bogdanm 0:9b334a45a8ff 128 return (float)value * (1.0f / (float)ADC_RANGE);
bogdanm 0:9b334a45a8ff 129 }
bogdanm 0:9b334a45a8ff 130
bogdanm 0:9b334a45a8ff 131 #endif