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vendor/NXP/LPC4088/hal/analogin_api.c@10:3bc89ef62ce7, 2013-06-14 (annotated)

Committer:
emilmont
Date:
Fri Jun 14 17:49:17 2013 +0100
Revision:
10:3bc89ef62ce7
Unify mbed library sources

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emilmont 10:3bc89ef62ce7 1 /* mbed Microcontroller Library
emilmont 10:3bc89ef62ce7 2 * Copyright (c) 2006-2013 ARM Limited
emilmont 10:3bc89ef62ce7 3 *
emilmont 10:3bc89ef62ce7 4 * Licensed under the Apache License, Version 2.0 (the "License");
emilmont 10:3bc89ef62ce7 5 * you may not use this file except in compliance with the License.
emilmont 10:3bc89ef62ce7 6 * You may obtain a copy of the License at
emilmont 10:3bc89ef62ce7 7 *
emilmont 10:3bc89ef62ce7 8 * http://www.apache.org/licenses/LICENSE-2.0
emilmont 10:3bc89ef62ce7 9 *
emilmont 10:3bc89ef62ce7 10 * Unless required by applicable law or agreed to in writing, software
emilmont 10:3bc89ef62ce7 11 * distributed under the License is distributed on an "AS IS" BASIS,
emilmont 10:3bc89ef62ce7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
emilmont 10:3bc89ef62ce7 13 * See the License for the specific language governing permissions and
emilmont 10:3bc89ef62ce7 14 * limitations under the License.
emilmont 10:3bc89ef62ce7 15 */
emilmont 10:3bc89ef62ce7 16 #include "analogin_api.h"
emilmont 10:3bc89ef62ce7 17 #include "cmsis.h"
emilmont 10:3bc89ef62ce7 18 #include "pinmap.h"
emilmont 10:3bc89ef62ce7 19 #include "error.h"
emilmont 10:3bc89ef62ce7 20
emilmont 10:3bc89ef62ce7 21 #define ANALOGIN_MEDIAN_FILTER 1
emilmont 10:3bc89ef62ce7 22
emilmont 10:3bc89ef62ce7 23 #define ADC_10BIT_RANGE 0x3FF
emilmont 10:3bc89ef62ce7 24 #define ADC_12BIT_RANGE 0xFFF
emilmont 10:3bc89ef62ce7 25
emilmont 10:3bc89ef62ce7 26 static inline int div_round_up(int x, int y) {
emilmont 10:3bc89ef62ce7 27 return (x + (y - 1)) / y;
emilmont 10:3bc89ef62ce7 28 }
emilmont 10:3bc89ef62ce7 29
emilmont 10:3bc89ef62ce7 30 static const PinMap PinMap_ADC[] = {
emilmont 10:3bc89ef62ce7 31 {P0_23, ADC0_0, 0x01},
emilmont 10:3bc89ef62ce7 32 {P0_24, ADC0_1, 0x01},
emilmont 10:3bc89ef62ce7 33 {P0_25, ADC0_2, 0x01},
emilmont 10:3bc89ef62ce7 34 {P0_26, ADC0_3, 0x01},
emilmont 10:3bc89ef62ce7 35 {P1_30, ADC0_4, 0x03},
emilmont 10:3bc89ef62ce7 36 {P1_31, ADC0_5, 0x03},
emilmont 10:3bc89ef62ce7 37 {P0_12, ADC0_6, 0x03},
emilmont 10:3bc89ef62ce7 38 {P0_13, ADC0_7, 0x03},
emilmont 10:3bc89ef62ce7 39 {NC , NC , 0 }
emilmont 10:3bc89ef62ce7 40 };
emilmont 10:3bc89ef62ce7 41
emilmont 10:3bc89ef62ce7 42 #define ADC_RANGE ADC_12BIT_RANGE
emilmont 10:3bc89ef62ce7 43
emilmont 10:3bc89ef62ce7 44 void analogin_init(analogin_t *obj, PinName pin) {
emilmont 10:3bc89ef62ce7 45 obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
emilmont 10:3bc89ef62ce7 46 if (obj->adc == (uint32_t)NC) {
emilmont 10:3bc89ef62ce7 47 error("ADC pin mapping failed");
emilmont 10:3bc89ef62ce7 48 }
emilmont 10:3bc89ef62ce7 49
emilmont 10:3bc89ef62ce7 50 // ensure power is turned on
emilmont 10:3bc89ef62ce7 51 LPC_SC->PCONP |= (1 << 12);
emilmont 10:3bc89ef62ce7 52
emilmont 10:3bc89ef62ce7 53 uint32_t PCLK = PeripheralClock;
emilmont 10:3bc89ef62ce7 54
emilmont 10:3bc89ef62ce7 55 // calculate minimum clock divider
emilmont 10:3bc89ef62ce7 56 // clkdiv = divider - 1
emilmont 10:3bc89ef62ce7 57 uint32_t MAX_ADC_CLK = 12400000;
emilmont 10:3bc89ef62ce7 58 uint32_t clkdiv = div_round_up(PCLK, MAX_ADC_CLK) - 1;
emilmont 10:3bc89ef62ce7 59
emilmont 10:3bc89ef62ce7 60 // Set the generic software-controlled ADC settings
emilmont 10:3bc89ef62ce7 61 LPC_ADC->CR = (0 << 0) // SEL: 0 = no channels selected
emilmont 10:3bc89ef62ce7 62 | (clkdiv << 8) // CLKDIV:
emilmont 10:3bc89ef62ce7 63 | (0 << 16) // BURST: 0 = software control
emilmont 10:3bc89ef62ce7 64 | (1 << 21) // PDN: 1 = operational
emilmont 10:3bc89ef62ce7 65 | (0 << 24) // START: 0 = no start
emilmont 10:3bc89ef62ce7 66 | (0 << 27); // EDGE: not applicable
emilmont 10:3bc89ef62ce7 67
emilmont 10:3bc89ef62ce7 68 // must enable analog mode (ADMODE = 0)
emilmont 10:3bc89ef62ce7 69 __IO uint32_t *reg = (__IO uint32_t*) (LPC_IOCON_BASE + 4 * pin);
emilmont 10:3bc89ef62ce7 70 *reg &= ~(1 << 7);
emilmont 10:3bc89ef62ce7 71
emilmont 10:3bc89ef62ce7 72 pinmap_pinout(pin, PinMap_ADC);
emilmont 10:3bc89ef62ce7 73 }
emilmont 10:3bc89ef62ce7 74
emilmont 10:3bc89ef62ce7 75 static inline uint32_t adc_read(analogin_t *obj) {
emilmont 10:3bc89ef62ce7 76 // Select the appropriate channel and start conversion
emilmont 10:3bc89ef62ce7 77 LPC_ADC->CR &= ~0xFF;
emilmont 10:3bc89ef62ce7 78 LPC_ADC->CR |= 1 << (int)obj->adc;
emilmont 10:3bc89ef62ce7 79 LPC_ADC->CR |= 1 << 24;
emilmont 10:3bc89ef62ce7 80
emilmont 10:3bc89ef62ce7 81 // Repeatedly get the sample data until DONE bit
emilmont 10:3bc89ef62ce7 82 unsigned int data;
emilmont 10:3bc89ef62ce7 83 do {
emilmont 10:3bc89ef62ce7 84 data = LPC_ADC->GDR;
emilmont 10:3bc89ef62ce7 85 } while ((data & ((unsigned int)1 << 31)) == 0);
emilmont 10:3bc89ef62ce7 86
emilmont 10:3bc89ef62ce7 87 // Stop conversion
emilmont 10:3bc89ef62ce7 88 LPC_ADC->CR &= ~(1 << 24);
emilmont 10:3bc89ef62ce7 89
emilmont 10:3bc89ef62ce7 90 return (data >> 4) & ADC_RANGE; // 12 bit
emilmont 10:3bc89ef62ce7 91 }
emilmont 10:3bc89ef62ce7 92
emilmont 10:3bc89ef62ce7 93 static inline void order(uint32_t *a, uint32_t *b) {
emilmont 10:3bc89ef62ce7 94 if (*a > *b) {
emilmont 10:3bc89ef62ce7 95 uint32_t t = *a;
emilmont 10:3bc89ef62ce7 96 *a = *b;
emilmont 10:3bc89ef62ce7 97 *b = t;
emilmont 10:3bc89ef62ce7 98 }
emilmont 10:3bc89ef62ce7 99 }
emilmont 10:3bc89ef62ce7 100
emilmont 10:3bc89ef62ce7 101 static inline uint32_t adc_read_u32(analogin_t *obj) {
emilmont 10:3bc89ef62ce7 102 uint32_t value;
emilmont 10:3bc89ef62ce7 103 #if ANALOGIN_MEDIAN_FILTER
emilmont 10:3bc89ef62ce7 104 uint32_t v1 = adc_read(obj);
emilmont 10:3bc89ef62ce7 105 uint32_t v2 = adc_read(obj);
emilmont 10:3bc89ef62ce7 106 uint32_t v3 = adc_read(obj);
emilmont 10:3bc89ef62ce7 107 order(&v1, &v2);
emilmont 10:3bc89ef62ce7 108 order(&v2, &v3);
emilmont 10:3bc89ef62ce7 109 order(&v1, &v2);
emilmont 10:3bc89ef62ce7 110 value = v2;
emilmont 10:3bc89ef62ce7 111 #else
emilmont 10:3bc89ef62ce7 112 value = adc_read(obj);
emilmont 10:3bc89ef62ce7 113 #endif
emilmont 10:3bc89ef62ce7 114 return value;
emilmont 10:3bc89ef62ce7 115 }
emilmont 10:3bc89ef62ce7 116
emilmont 10:3bc89ef62ce7 117 uint16_t analogin_read_u16(analogin_t *obj) {
emilmont 10:3bc89ef62ce7 118 uint32_t value = adc_read_u32(obj);
emilmont 10:3bc89ef62ce7 119
emilmont 10:3bc89ef62ce7 120 return (value << 4) | ((value >> 8) & 0x000F); // 12 bit
emilmont 10:3bc89ef62ce7 121 }
emilmont 10:3bc89ef62ce7 122
emilmont 10:3bc89ef62ce7 123 float analogin_read(analogin_t *obj) {
emilmont 10:3bc89ef62ce7 124 uint32_t value = adc_read_u32(obj);
emilmont 10:3bc89ef62ce7 125 return (float)value * (1.0f / (float)ADC_RANGE);
emilmont 10:3bc89ef62ce7 126 }