shao ziyang / mbed-src-kl05

mbed library sources

Dependents:   frdm_kl05z_gpio_test

Fork of mbed-src by mbed official

targets/hal/TARGET_NXP/TARGET_LPC408X/analogin_api.c@29:6ac4027eff2b, 2013-09-23 (annotated)

Committer:
mbed_official
Date:
Mon Sep 23 11:30:07 2013 +0100
Revision:
29:6ac4027eff2b
Parent:
15:4892fe388435
Child:
227:7bd0639b8911
Synchronized with git revision 4e23b72a78e8adfcaf3e52831780eca6d7a7bafe

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 15:4892fe388435 1 /* mbed Microcontroller Library
bogdanm 15:4892fe388435 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 15:4892fe388435 3 *
bogdanm 15:4892fe388435 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 15:4892fe388435 5 * you may not use this file except in compliance with the License.
bogdanm 15:4892fe388435 6 * You may obtain a copy of the License at
bogdanm 15:4892fe388435 7 *
bogdanm 15:4892fe388435 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 15:4892fe388435 9 *
bogdanm 15:4892fe388435 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 15:4892fe388435 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 15:4892fe388435 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 15:4892fe388435 13 * See the License for the specific language governing permissions and
bogdanm 15:4892fe388435 14 * limitations under the License.
bogdanm 15:4892fe388435 15 */
bogdanm 15:4892fe388435 16 #include "analogin_api.h"
bogdanm 15:4892fe388435 17 #include "cmsis.h"
bogdanm 15:4892fe388435 18 #include "pinmap.h"
bogdanm 15:4892fe388435 19 #include "error.h"
bogdanm 15:4892fe388435 20
bogdanm 15:4892fe388435 21 #define ANALOGIN_MEDIAN_FILTER 1
bogdanm 15:4892fe388435 22
bogdanm 15:4892fe388435 23 #define ADC_10BIT_RANGE 0x3FF
bogdanm 15:4892fe388435 24 #define ADC_12BIT_RANGE 0xFFF
bogdanm 15:4892fe388435 25
bogdanm 15:4892fe388435 26 static inline int div_round_up(int x, int y) {
bogdanm 15:4892fe388435 27 return (x + (y - 1)) / y;
bogdanm 15:4892fe388435 28 }
bogdanm 15:4892fe388435 29
bogdanm 15:4892fe388435 30 static const PinMap PinMap_ADC[] = {
bogdanm 15:4892fe388435 31 {P0_23, ADC0_0, 0x01},
bogdanm 15:4892fe388435 32 {P0_24, ADC0_1, 0x01},
bogdanm 15:4892fe388435 33 {P0_25, ADC0_2, 0x01},
bogdanm 15:4892fe388435 34 {P0_26, ADC0_3, 0x01},
bogdanm 15:4892fe388435 35 {P1_30, ADC0_4, 0x03},
bogdanm 15:4892fe388435 36 {P1_31, ADC0_5, 0x03},
bogdanm 15:4892fe388435 37 {P0_12, ADC0_6, 0x03},
bogdanm 15:4892fe388435 38 {P0_13, ADC0_7, 0x03},
bogdanm 15:4892fe388435 39 {NC , NC , 0 }
bogdanm 15:4892fe388435 40 };
bogdanm 15:4892fe388435 41
bogdanm 15:4892fe388435 42 #define ADC_RANGE ADC_12BIT_RANGE
bogdanm 15:4892fe388435 43
bogdanm 15:4892fe388435 44 void analogin_init(analogin_t *obj, PinName pin) {
bogdanm 15:4892fe388435 45 obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
mbed_official 29:6ac4027eff2b 46 if (obj->adc == (ADCName)NC) {
bogdanm 15:4892fe388435 47 error("ADC pin mapping failed");
bogdanm 15:4892fe388435 48 }
bogdanm 15:4892fe388435 49
bogdanm 15:4892fe388435 50 // ensure power is turned on
bogdanm 15:4892fe388435 51 LPC_SC->PCONP |= (1 << 12);
bogdanm 15:4892fe388435 52
bogdanm 15:4892fe388435 53 uint32_t PCLK = PeripheralClock;
bogdanm 15:4892fe388435 54
bogdanm 15:4892fe388435 55 // calculate minimum clock divider
bogdanm 15:4892fe388435 56 // clkdiv = divider - 1
bogdanm 15:4892fe388435 57 uint32_t MAX_ADC_CLK = 12400000;
bogdanm 15:4892fe388435 58 uint32_t clkdiv = div_round_up(PCLK, MAX_ADC_CLK) - 1;
bogdanm 15:4892fe388435 59
bogdanm 15:4892fe388435 60 // Set the generic software-controlled ADC settings
bogdanm 15:4892fe388435 61 LPC_ADC->CR = (0 << 0) // SEL: 0 = no channels selected
bogdanm 15:4892fe388435 62 | (clkdiv << 8) // CLKDIV:
bogdanm 15:4892fe388435 63 | (0 << 16) // BURST: 0 = software control
bogdanm 15:4892fe388435 64 | (1 << 21) // PDN: 1 = operational
bogdanm 15:4892fe388435 65 | (0 << 24) // START: 0 = no start
bogdanm 15:4892fe388435 66 | (0 << 27); // EDGE: not applicable
bogdanm 15:4892fe388435 67
bogdanm 15:4892fe388435 68 // must enable analog mode (ADMODE = 0)
bogdanm 15:4892fe388435 69 __IO uint32_t *reg = (__IO uint32_t*) (LPC_IOCON_BASE + 4 * pin);
bogdanm 15:4892fe388435 70 *reg &= ~(1 << 7);
bogdanm 15:4892fe388435 71
bogdanm 15:4892fe388435 72 pinmap_pinout(pin, PinMap_ADC);
bogdanm 15:4892fe388435 73 }
bogdanm 15:4892fe388435 74
bogdanm 15:4892fe388435 75 static inline uint32_t adc_read(analogin_t *obj) {
bogdanm 15:4892fe388435 76 // Select the appropriate channel and start conversion
bogdanm 15:4892fe388435 77 LPC_ADC->CR &= ~0xFF;
bogdanm 15:4892fe388435 78 LPC_ADC->CR |= 1 << (int)obj->adc;
bogdanm 15:4892fe388435 79 LPC_ADC->CR |= 1 << 24;
bogdanm 15:4892fe388435 80
bogdanm 15:4892fe388435 81 // Repeatedly get the sample data until DONE bit
bogdanm 15:4892fe388435 82 unsigned int data;
bogdanm 15:4892fe388435 83 do {
bogdanm 15:4892fe388435 84 data = LPC_ADC->GDR;
bogdanm 15:4892fe388435 85 } while ((data & ((unsigned int)1 << 31)) == 0);
bogdanm 15:4892fe388435 86
bogdanm 15:4892fe388435 87 // Stop conversion
bogdanm 15:4892fe388435 88 LPC_ADC->CR &= ~(1 << 24);
bogdanm 15:4892fe388435 89
bogdanm 15:4892fe388435 90 return (data >> 4) & ADC_RANGE; // 12 bit
bogdanm 15:4892fe388435 91 }
bogdanm 15:4892fe388435 92
bogdanm 15:4892fe388435 93 static inline void order(uint32_t *a, uint32_t *b) {
bogdanm 15:4892fe388435 94 if (*a > *b) {
bogdanm 15:4892fe388435 95 uint32_t t = *a;
bogdanm 15:4892fe388435 96 *a = *b;
bogdanm 15:4892fe388435 97 *b = t;
bogdanm 15:4892fe388435 98 }
bogdanm 15:4892fe388435 99 }
bogdanm 15:4892fe388435 100
bogdanm 15:4892fe388435 101 static inline uint32_t adc_read_u32(analogin_t *obj) {
bogdanm 15:4892fe388435 102 uint32_t value;
bogdanm 15:4892fe388435 103 #if ANALOGIN_MEDIAN_FILTER
bogdanm 15:4892fe388435 104 uint32_t v1 = adc_read(obj);
bogdanm 15:4892fe388435 105 uint32_t v2 = adc_read(obj);
bogdanm 15:4892fe388435 106 uint32_t v3 = adc_read(obj);
bogdanm 15:4892fe388435 107 order(&v1, &v2);
bogdanm 15:4892fe388435 108 order(&v2, &v3);
bogdanm 15:4892fe388435 109 order(&v1, &v2);
bogdanm 15:4892fe388435 110 value = v2;
bogdanm 15:4892fe388435 111 #else
bogdanm 15:4892fe388435 112 value = adc_read(obj);
bogdanm 15:4892fe388435 113 #endif
bogdanm 15:4892fe388435 114 return value;
bogdanm 15:4892fe388435 115 }
bogdanm 15:4892fe388435 116
bogdanm 15:4892fe388435 117 uint16_t analogin_read_u16(analogin_t *obj) {
bogdanm 15:4892fe388435 118 uint32_t value = adc_read_u32(obj);
bogdanm 15:4892fe388435 119
bogdanm 15:4892fe388435 120 return (value << 4) | ((value >> 8) & 0x000F); // 12 bit
bogdanm 15:4892fe388435 121 }
bogdanm 15:4892fe388435 122
bogdanm 15:4892fe388435 123 float analogin_read(analogin_t *obj) {
bogdanm 15:4892fe388435 124 uint32_t value = adc_read_u32(obj);
bogdanm 15:4892fe388435 125 return (float)value * (1.0f / (float)ADC_RANGE);
bogdanm 15:4892fe388435 126 }