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targets/hal/TARGET_NXP/TARGET_LPC13XX/analogin_api.c@0:9b334a45a8ff, 2015-10-01 (annotated)

Committer:
bogdanm
Date:
Thu Oct 01 15:25:22 2015 +0300
Revision:
0:9b334a45a8ff
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 "mbed_error.h"
bogdanm 0:9b334a45a8ff 21
bogdanm 0:9b334a45a8ff 22 #define ANALOGIN_MEDIAN_FILTER 1
bogdanm 0:9b334a45a8ff 23
bogdanm 0:9b334a45a8ff 24 #define ADC_10BIT_RANGE 0x3FF
bogdanm 0:9b334a45a8ff 25 #define ADC_12BIT_RANGE 0xFFF
bogdanm 0:9b334a45a8ff 26
bogdanm 0:9b334a45a8ff 27 static inline int div_round_up(int x, int y) {
bogdanm 0:9b334a45a8ff 28 return (x + (y - 1)) / y;
bogdanm 0:9b334a45a8ff 29 }
bogdanm 0:9b334a45a8ff 30
bogdanm 0:9b334a45a8ff 31 static const PinMap PinMap_ADC[] = {
bogdanm 0:9b334a45a8ff 32 {P0_11, ADC0_0, 0x02},
bogdanm 0:9b334a45a8ff 33 {P0_12, ADC0_1, 0x02},
bogdanm 0:9b334a45a8ff 34 {P0_13, ADC0_2, 0x02},
bogdanm 0:9b334a45a8ff 35 {P0_14, ADC0_3, 0x02},
bogdanm 0:9b334a45a8ff 36 {P0_15, ADC0_4, 0x02},
bogdanm 0:9b334a45a8ff 37 {P0_16, ADC0_5, 0x01},
bogdanm 0:9b334a45a8ff 38 {P0_22, ADC0_6, 0x01},
bogdanm 0:9b334a45a8ff 39 {P0_23, ADC0_7, 0x01},
bogdanm 0:9b334a45a8ff 40 {NC , NC , 0 }
bogdanm 0:9b334a45a8ff 41 };
bogdanm 0:9b334a45a8ff 42
bogdanm 0:9b334a45a8ff 43 #define LPC_IOCON0_BASE (LPC_IOCON_BASE)
bogdanm 0:9b334a45a8ff 44 #define LPC_IOCON1_BASE (LPC_IOCON_BASE + 0x60)
bogdanm 0:9b334a45a8ff 45
bogdanm 0:9b334a45a8ff 46 #define ADC_RANGE ADC_10BIT_RANGE
bogdanm 0:9b334a45a8ff 47
bogdanm 0:9b334a45a8ff 48 void analogin_init(analogin_t *obj, PinName pin) {
bogdanm 0:9b334a45a8ff 49 obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
bogdanm 0:9b334a45a8ff 50 MBED_ASSERT(obj->adc != (ADCName)NC);
bogdanm 0:9b334a45a8ff 51
bogdanm 0:9b334a45a8ff 52 // Power up ADC
bogdanm 0:9b334a45a8ff 53 LPC_SYSCON->PDRUNCFG &= ~ (1 << 4);
bogdanm 0:9b334a45a8ff 54 LPC_SYSCON->SYSAHBCLKCTRL |= ((uint32_t)1 << 13);
bogdanm 0:9b334a45a8ff 55
bogdanm 0:9b334a45a8ff 56 uint32_t pin_number = (uint32_t)pin;
bogdanm 0:9b334a45a8ff 57 __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));
bogdanm 0:9b334a45a8ff 58
bogdanm 0:9b334a45a8ff 59 // set pin to ADC mode
bogdanm 0:9b334a45a8ff 60 *reg &= ~(1 << 7); // set ADMODE = 0 (analog mode)
bogdanm 0:9b334a45a8ff 61
bogdanm 0:9b334a45a8ff 62 uint32_t PCLK = SystemCoreClock;
bogdanm 0:9b334a45a8ff 63 uint32_t MAX_ADC_CLK = 4500000;
bogdanm 0:9b334a45a8ff 64 uint32_t clkdiv = div_round_up(PCLK, MAX_ADC_CLK) - 1;
bogdanm 0:9b334a45a8ff 65
bogdanm 0:9b334a45a8ff 66 LPC_ADC->CR = (0 << 0) // no channels selected
bogdanm 0:9b334a45a8ff 67 | (clkdiv << 8) // max of 4.5MHz
bogdanm 0:9b334a45a8ff 68 | (0 << 16) // BURST = 0, software controlled
bogdanm 0:9b334a45a8ff 69 | ( 0 << 17 ); // CLKS = 0, not applicable
bogdanm 0:9b334a45a8ff 70
bogdanm 0:9b334a45a8ff 71 pinmap_pinout(pin, PinMap_ADC);
bogdanm 0:9b334a45a8ff 72 }
bogdanm 0:9b334a45a8ff 73
bogdanm 0:9b334a45a8ff 74 static inline uint32_t adc_read(analogin_t *obj) {
bogdanm 0:9b334a45a8ff 75 // Select the appropriate channel and start conversion
bogdanm 0:9b334a45a8ff 76 LPC_ADC->CR &= ~0xFF;
bogdanm 0:9b334a45a8ff 77 LPC_ADC->CR |= 1 << (int)obj->adc;
bogdanm 0:9b334a45a8ff 78 LPC_ADC->CR |= 1 << 24;
bogdanm 0:9b334a45a8ff 79
bogdanm 0:9b334a45a8ff 80 // Repeatedly get the sample data until DONE bit
bogdanm 0:9b334a45a8ff 81 unsigned int data;
bogdanm 0:9b334a45a8ff 82 do {
bogdanm 0:9b334a45a8ff 83 data = LPC_ADC->GDR;
bogdanm 0:9b334a45a8ff 84 } while ((data & ((unsigned int)1 << 31)) == 0);
bogdanm 0:9b334a45a8ff 85
bogdanm 0:9b334a45a8ff 86 // Stop conversion
bogdanm 0:9b334a45a8ff 87 LPC_ADC->CR &= ~(1 << 24);
bogdanm 0:9b334a45a8ff 88
bogdanm 0:9b334a45a8ff 89 return (data >> 6) & ADC_RANGE; // 10 bit
bogdanm 0:9b334a45a8ff 90 }
bogdanm 0:9b334a45a8ff 91
bogdanm 0:9b334a45a8ff 92 static inline void order(uint32_t *a, uint32_t *b) {
bogdanm 0:9b334a45a8ff 93 if (*a > *b) {
bogdanm 0:9b334a45a8ff 94 uint32_t t = *a;
bogdanm 0:9b334a45a8ff 95 *a = *b;
bogdanm 0:9b334a45a8ff 96 *b = t;
bogdanm 0:9b334a45a8ff 97 }
bogdanm 0:9b334a45a8ff 98 }
bogdanm 0:9b334a45a8ff 99
bogdanm 0:9b334a45a8ff 100 static inline uint32_t adc_read_u32(analogin_t *obj) {
bogdanm 0:9b334a45a8ff 101 uint32_t value;
bogdanm 0:9b334a45a8ff 102 #if ANALOGIN_MEDIAN_FILTER
bogdanm 0:9b334a45a8ff 103 uint32_t v1 = adc_read(obj);
bogdanm 0:9b334a45a8ff 104 uint32_t v2 = adc_read(obj);
bogdanm 0:9b334a45a8ff 105 uint32_t v3 = adc_read(obj);
bogdanm 0:9b334a45a8ff 106 order(&v1, &v2);
bogdanm 0:9b334a45a8ff 107 order(&v2, &v3);
bogdanm 0:9b334a45a8ff 108 order(&v1, &v2);
bogdanm 0:9b334a45a8ff 109 value = v2;
bogdanm 0:9b334a45a8ff 110 #else
bogdanm 0:9b334a45a8ff 111 value = adc_read(obj);
bogdanm 0:9b334a45a8ff 112 #endif
bogdanm 0:9b334a45a8ff 113 return value;
bogdanm 0:9b334a45a8ff 114 }
bogdanm 0:9b334a45a8ff 115
bogdanm 0:9b334a45a8ff 116 uint16_t analogin_read_u16(analogin_t *obj) {
bogdanm 0:9b334a45a8ff 117 uint32_t value = adc_read_u32(obj);
bogdanm 0:9b334a45a8ff 118
bogdanm 0:9b334a45a8ff 119 return (value << 6) | ((value >> 4) & 0x003F); // 10 bit
bogdanm 0:9b334a45a8ff 120 }
bogdanm 0:9b334a45a8ff 121
bogdanm 0:9b334a45a8ff 122 float analogin_read(analogin_t *obj) {
bogdanm 0:9b334a45a8ff 123 uint32_t value = adc_read_u32(obj);
bogdanm 0:9b334a45a8ff 124 return (float)value * (1.0f / (float)ADC_RANGE);
bogdanm 0:9b334a45a8ff 125 }