Lee Kai Xuan / mbed-os

mbed-os

Fork of mbed-os by erkin yucel

targets/TARGET_NXP/TARGET_LPC11UXX/analogin_api.c@1:3deb71413561, 2017-07-20 (annotated)

Committer:
xuaner
Date:
Thu Jul 20 14:26:57 2017 +0000
Revision:
1:3deb71413561
Parent:
0:f269e3021894 
mbed_os

Who changed what in which revision?

UserRevisionLine numberNew contents of line
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 "mbed_error.h"
elessair 0:f269e3021894 21 #include "PeripheralPins.h" // For the Peripheral to Pin Definitions found in the individual Target's Platform
elessair 0:f269e3021894 22
elessair 0:f269e3021894 23 #define ANALOGIN_MEDIAN_FILTER 1
elessair 0:f269e3021894 24
elessair 0:f269e3021894 25 #define ADC_10BIT_RANGE 0x3FF
elessair 0:f269e3021894 26 #define ADC_12BIT_RANGE 0xFFF
elessair 0:f269e3021894 27
elessair 0:f269e3021894 28 static inline int div_round_up(int x, int y) {
elessair 0:f269e3021894 29 return (x + (y - 1)) / y;
elessair 0:f269e3021894 30 }
elessair 0:f269e3021894 31
elessair 0:f269e3021894 32 #define LPC_IOCON0_BASE (LPC_IOCON_BASE)
elessair 0:f269e3021894 33 #define LPC_IOCON1_BASE (LPC_IOCON_BASE + 0x60)
elessair 0:f269e3021894 34
elessair 0:f269e3021894 35 #define ADC_RANGE ADC_10BIT_RANGE
elessair 0:f269e3021894 36
elessair 0:f269e3021894 37 void analogin_init(analogin_t *obj, PinName pin) {
elessair 0:f269e3021894 38 obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
elessair 0:f269e3021894 39 MBED_ASSERT(obj->adc != (ADCName)NC);
elessair 0:f269e3021894 40
elessair 0:f269e3021894 41 // Power up ADC
elessair 0:f269e3021894 42 LPC_SYSCON->PDRUNCFG &= ~ (1 << 4);
elessair 0:f269e3021894 43 LPC_SYSCON->SYSAHBCLKCTRL |= ((uint32_t)1 << 13);
elessair 0:f269e3021894 44
elessair 0:f269e3021894 45 uint32_t pin_number = (uint32_t)pin;
elessair 0:f269e3021894 46 __IO uint32_t *reg = (pin_number < 32) ? (__IO uint32_t*)(LPC_IOCON0_BASE + 4 * pin_number) : (__IO uint32_t*)(LPC_IOCON1_BASE + 4 * (pin_number - 32));
elessair 0:f269e3021894 47
elessair 0:f269e3021894 48 // set pin to ADC mode
elessair 0:f269e3021894 49 *reg &= ~(1 << 7); // set ADMODE = 0 (analog mode)
elessair 0:f269e3021894 50
elessair 0:f269e3021894 51 uint32_t PCLK = SystemCoreClock;
elessair 0:f269e3021894 52 uint32_t MAX_ADC_CLK = 4500000;
elessair 0:f269e3021894 53 uint32_t clkdiv = div_round_up(PCLK, MAX_ADC_CLK) - 1;
elessair 0:f269e3021894 54
elessair 0:f269e3021894 55 LPC_ADC->CR = (0 << 0) // no channels selected
elessair 0:f269e3021894 56 | (clkdiv << 8) // max of 4.5MHz
elessair 0:f269e3021894 57 | (0 << 16) // BURST = 0, software controlled
elessair 0:f269e3021894 58 | ( 0 << 17 ); // CLKS = 0, not applicable
elessair 0:f269e3021894 59
elessair 0:f269e3021894 60 pinmap_pinout(pin, PinMap_ADC);
elessair 0:f269e3021894 61 }
elessair 0:f269e3021894 62
elessair 0:f269e3021894 63 static inline uint32_t adc_read(analogin_t *obj) {
elessair 0:f269e3021894 64 // Select the appropriate channel and start conversion
elessair 0:f269e3021894 65 LPC_ADC->CR &= ~0xFF;
elessair 0:f269e3021894 66 LPC_ADC->CR |= 1 << (int)obj->adc;
elessair 0:f269e3021894 67 LPC_ADC->CR |= 1 << 24;
elessair 0:f269e3021894 68
elessair 0:f269e3021894 69 // Repeatedly get the sample data until DONE bit
elessair 0:f269e3021894 70 unsigned int data;
elessair 0:f269e3021894 71 do {
elessair 0:f269e3021894 72 data = LPC_ADC->GDR;
elessair 0:f269e3021894 73 } while ((data & ((unsigned int)1 << 31)) == 0);
elessair 0:f269e3021894 74
elessair 0:f269e3021894 75 // Stop conversion
elessair 0:f269e3021894 76 LPC_ADC->CR &= ~(1 << 24);
elessair 0:f269e3021894 77
elessair 0:f269e3021894 78 return (data >> 6) & ADC_RANGE; // 10 bit
elessair 0:f269e3021894 79 }
elessair 0:f269e3021894 80
elessair 0:f269e3021894 81 static inline void order(uint32_t *a, uint32_t *b) {
elessair 0:f269e3021894 82 if (*a > *b) {
elessair 0:f269e3021894 83 uint32_t t = *a;
elessair 0:f269e3021894 84 *a = *b;
elessair 0:f269e3021894 85 *b = t;
elessair 0:f269e3021894 86 }
elessair 0:f269e3021894 87 }
elessair 0:f269e3021894 88
elessair 0:f269e3021894 89 static inline uint32_t adc_read_u32(analogin_t *obj) {
elessair 0:f269e3021894 90 uint32_t value;
elessair 0:f269e3021894 91 #if ANALOGIN_MEDIAN_FILTER
elessair 0:f269e3021894 92 uint32_t v1 = adc_read(obj);
elessair 0:f269e3021894 93 uint32_t v2 = adc_read(obj);
elessair 0:f269e3021894 94 uint32_t v3 = adc_read(obj);
elessair 0:f269e3021894 95 order(&v1, &v2);
elessair 0:f269e3021894 96 order(&v2, &v3);
elessair 0:f269e3021894 97 order(&v1, &v2);
elessair 0:f269e3021894 98 value = v2;
elessair 0:f269e3021894 99 #else
elessair 0:f269e3021894 100 value = adc_read(obj);
elessair 0:f269e3021894 101 #endif
elessair 0:f269e3021894 102 return value;
elessair 0:f269e3021894 103 }
elessair 0:f269e3021894 104
elessair 0:f269e3021894 105 uint16_t analogin_read_u16(analogin_t *obj) {
elessair 0:f269e3021894 106 uint32_t value = adc_read_u32(obj);
elessair 0:f269e3021894 107
elessair 0:f269e3021894 108 return (value << 6) | ((value >> 4) & 0x003F); // 10 bit
elessair 0:f269e3021894 109 }
elessair 0:f269e3021894 110
elessair 0:f269e3021894 111 float analogin_read(analogin_t *obj) {
elessair 0:f269e3021894 112 uint32_t value = adc_read_u32(obj);
elessair 0:f269e3021894 113 return (float)value * (1.0f / (float)ADC_RANGE);
elessair 0:f269e3021894 114 }