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targets/hal/TARGET_NXP/TARGET_LPC2460/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) 2006-2015 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
bogdanm 0:9b334a45a8ff 21 #define ANALOGIN_MEDIAN_FILTER 1
bogdanm 0:9b334a45a8ff 22
bogdanm 0:9b334a45a8ff 23 #define ADC_10BIT_RANGE 0x3FF
bogdanm 0:9b334a45a8ff 24 #define ADC_12BIT_RANGE 0xFFF
bogdanm 0:9b334a45a8ff 25
bogdanm 0:9b334a45a8ff 26 static inline int div_round_up(int x, int y) {
bogdanm 0:9b334a45a8ff 27 return (x + (y - 1)) / y;
bogdanm 0:9b334a45a8ff 28 }
bogdanm 0:9b334a45a8ff 29
bogdanm 0:9b334a45a8ff 30 static const PinMap PinMap_ADC[] = {
bogdanm 0:9b334a45a8ff 31 {P0_23, ADC0_0, 1},
bogdanm 0:9b334a45a8ff 32 {P0_24, ADC0_1, 1},
bogdanm 0:9b334a45a8ff 33 {P0_25, ADC0_2, 1},
bogdanm 0:9b334a45a8ff 34 {P0_26, ADC0_3, 1},
bogdanm 0:9b334a45a8ff 35 {P1_30, ADC0_4, 3},
bogdanm 0:9b334a45a8ff 36 {P1_31, ADC0_5, 3},
bogdanm 0:9b334a45a8ff 37 {P0_12, ADC0_6, 3},
bogdanm 0:9b334a45a8ff 38 {P0_13, ADC0_7, 3},
bogdanm 0:9b334a45a8ff 39 {NC, NC, 0}
bogdanm 0:9b334a45a8ff 40 };
bogdanm 0:9b334a45a8ff 41
bogdanm 0:9b334a45a8ff 42 #define ADC_RANGE ADC_10BIT_RANGE
bogdanm 0:9b334a45a8ff 43
bogdanm 0:9b334a45a8ff 44
bogdanm 0:9b334a45a8ff 45 void analogin_init(analogin_t *obj, PinName pin) {
bogdanm 0:9b334a45a8ff 46 obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
bogdanm 0:9b334a45a8ff 47 MBED_ASSERT(obj->adc != (ADCName)NC);
bogdanm 0:9b334a45a8ff 48
bogdanm 0:9b334a45a8ff 49 // ensure power is turned on
bogdanm 0:9b334a45a8ff 50 LPC_SC->PCONP |= (1 << PCADC);
bogdanm 0:9b334a45a8ff 51
bogdanm 0:9b334a45a8ff 52 // set PCLK of ADC to /1
bogdanm 0:9b334a45a8ff 53 LPC_SC->PCLKSEL0 &= ~(0x3 << 24);
bogdanm 0:9b334a45a8ff 54 LPC_SC->PCLKSEL0 |= (0x1 << 24);
bogdanm 0:9b334a45a8ff 55 uint32_t PCLK = SystemCoreClock;
bogdanm 0:9b334a45a8ff 56
bogdanm 0:9b334a45a8ff 57 // calculate minimum clock divider
bogdanm 0:9b334a45a8ff 58 // clkdiv = divider - 1
bogdanm 0:9b334a45a8ff 59 uint32_t MAX_ADC_CLK = 4500000;
bogdanm 0:9b334a45a8ff 60 uint32_t clkdiv = div_round_up(PCLK, MAX_ADC_CLK) - 1;
bogdanm 0:9b334a45a8ff 61
bogdanm 0:9b334a45a8ff 62 // Set the generic software-controlled ADC settings
bogdanm 0:9b334a45a8ff 63 LPC_ADC->ADCR = (0 << 0) // SEL: 0 = no channels selected
bogdanm 0:9b334a45a8ff 64 | (clkdiv << 8) // CLKDIV: PCLK max ~= 25MHz, /25 to give safe 1MHz at fastest
bogdanm 0:9b334a45a8ff 65 | (0 << 16) // BURST: 0 = software control
bogdanm 0:9b334a45a8ff 66 | (0 << 17) // CLKS: not applicable
bogdanm 0:9b334a45a8ff 67 | (1 << 21) // PDN: 1 = operational
bogdanm 0:9b334a45a8ff 68 | (0 << 24) // START: 0 = no start
bogdanm 0:9b334a45a8ff 69 | (0 << 27); // EDGE: 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->ADCR &= ~0xFF;
bogdanm 0:9b334a45a8ff 77 LPC_ADC->ADCR |= 1 << (int)obj->adc;
bogdanm 0:9b334a45a8ff 78 LPC_ADC->ADCR |= 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->ADGDR;
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->ADCR &= ~(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 }