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@227:7bd0639b8911, 2014-06-11 (annotated)

Committer:
mbed_official
Date:
Wed Jun 11 16:00:09 2014 +0100
Revision:
227:7bd0639b8911
Parent:
29:6ac4027eff2b
Child:
250:a49055e7a707
Synchronized with git revision d58d532ebc0e0a96f4fffb8edefc082b71b964af



Full URL: https://github.com/mbedmicro/mbed/commit/d58d532ebc0e0a96f4fffb8edefc082b71b964af/

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 */
mbed_official 227:7bd0639b8911 16 #include "mbed_assert.h"
bogdanm 15:4892fe388435 17 #include "analogin_api.h"
bogdanm 15:4892fe388435 18 #include "cmsis.h"
bogdanm 15:4892fe388435 19 #include "pinmap.h"
bogdanm 15:4892fe388435 20 #include "error.h"
bogdanm 15:4892fe388435 21
bogdanm 15:4892fe388435 22 #define ANALOGIN_MEDIAN_FILTER 1
bogdanm 15:4892fe388435 23
bogdanm 15:4892fe388435 24 #define ADC_10BIT_RANGE 0x3FF
bogdanm 15:4892fe388435 25 #define ADC_12BIT_RANGE 0xFFF
bogdanm 15:4892fe388435 26
bogdanm 15:4892fe388435 27 static inline int div_round_up(int x, int y) {
bogdanm 15:4892fe388435 28 return (x + (y - 1)) / y;
bogdanm 15:4892fe388435 29 }
bogdanm 15:4892fe388435 30
bogdanm 15:4892fe388435 31 static const PinMap PinMap_ADC[] = {
bogdanm 15:4892fe388435 32 {P0_23, ADC0_0, 0x01},
bogdanm 15:4892fe388435 33 {P0_24, ADC0_1, 0x01},
bogdanm 15:4892fe388435 34 {P0_25, ADC0_2, 0x01},
bogdanm 15:4892fe388435 35 {P0_26, ADC0_3, 0x01},
bogdanm 15:4892fe388435 36 {P1_30, ADC0_4, 0x03},
bogdanm 15:4892fe388435 37 {P1_31, ADC0_5, 0x03},
bogdanm 15:4892fe388435 38 {P0_12, ADC0_6, 0x03},
bogdanm 15:4892fe388435 39 {P0_13, ADC0_7, 0x03},
bogdanm 15:4892fe388435 40 {NC , NC , 0 }
bogdanm 15:4892fe388435 41 };
bogdanm 15:4892fe388435 42
bogdanm 15:4892fe388435 43 #define ADC_RANGE ADC_12BIT_RANGE
bogdanm 15:4892fe388435 44
bogdanm 15:4892fe388435 45 void analogin_init(analogin_t *obj, PinName pin) {
bogdanm 15:4892fe388435 46 obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
mbed_official 227:7bd0639b8911 47 MBED_ASSERT(obj->adc != (ADCName)NC);
bogdanm 15:4892fe388435 48
bogdanm 15:4892fe388435 49 // ensure power is turned on
bogdanm 15:4892fe388435 50 LPC_SC->PCONP |= (1 << 12);
bogdanm 15:4892fe388435 51
bogdanm 15:4892fe388435 52 uint32_t PCLK = PeripheralClock;
bogdanm 15:4892fe388435 53
bogdanm 15:4892fe388435 54 // calculate minimum clock divider
bogdanm 15:4892fe388435 55 // clkdiv = divider - 1
bogdanm 15:4892fe388435 56 uint32_t MAX_ADC_CLK = 12400000;
bogdanm 15:4892fe388435 57 uint32_t clkdiv = div_round_up(PCLK, MAX_ADC_CLK) - 1;
bogdanm 15:4892fe388435 58
bogdanm 15:4892fe388435 59 // Set the generic software-controlled ADC settings
bogdanm 15:4892fe388435 60 LPC_ADC->CR = (0 << 0) // SEL: 0 = no channels selected
bogdanm 15:4892fe388435 61 | (clkdiv << 8) // CLKDIV:
bogdanm 15:4892fe388435 62 | (0 << 16) // BURST: 0 = software control
bogdanm 15:4892fe388435 63 | (1 << 21) // PDN: 1 = operational
bogdanm 15:4892fe388435 64 | (0 << 24) // START: 0 = no start
bogdanm 15:4892fe388435 65 | (0 << 27); // EDGE: not applicable
bogdanm 15:4892fe388435 66
bogdanm 15:4892fe388435 67 // must enable analog mode (ADMODE = 0)
bogdanm 15:4892fe388435 68 __IO uint32_t *reg = (__IO uint32_t*) (LPC_IOCON_BASE + 4 * pin);
bogdanm 15:4892fe388435 69 *reg &= ~(1 << 7);
bogdanm 15:4892fe388435 70
bogdanm 15:4892fe388435 71 pinmap_pinout(pin, PinMap_ADC);
bogdanm 15:4892fe388435 72 }
bogdanm 15:4892fe388435 73
bogdanm 15:4892fe388435 74 static inline uint32_t adc_read(analogin_t *obj) {
bogdanm 15:4892fe388435 75 // Select the appropriate channel and start conversion
bogdanm 15:4892fe388435 76 LPC_ADC->CR &= ~0xFF;
bogdanm 15:4892fe388435 77 LPC_ADC->CR |= 1 << (int)obj->adc;
bogdanm 15:4892fe388435 78 LPC_ADC->CR |= 1 << 24;
bogdanm 15:4892fe388435 79
bogdanm 15:4892fe388435 80 // Repeatedly get the sample data until DONE bit
bogdanm 15:4892fe388435 81 unsigned int data;
bogdanm 15:4892fe388435 82 do {
bogdanm 15:4892fe388435 83 data = LPC_ADC->GDR;
bogdanm 15:4892fe388435 84 } while ((data & ((unsigned int)1 << 31)) == 0);
bogdanm 15:4892fe388435 85
bogdanm 15:4892fe388435 86 // Stop conversion
bogdanm 15:4892fe388435 87 LPC_ADC->CR &= ~(1 << 24);
bogdanm 15:4892fe388435 88
bogdanm 15:4892fe388435 89 return (data >> 4) & ADC_RANGE; // 12 bit
bogdanm 15:4892fe388435 90 }
bogdanm 15:4892fe388435 91
bogdanm 15:4892fe388435 92 static inline void order(uint32_t *a, uint32_t *b) {
bogdanm 15:4892fe388435 93 if (*a > *b) {
bogdanm 15:4892fe388435 94 uint32_t t = *a;
bogdanm 15:4892fe388435 95 *a = *b;
bogdanm 15:4892fe388435 96 *b = t;
bogdanm 15:4892fe388435 97 }
bogdanm 15:4892fe388435 98 }
bogdanm 15:4892fe388435 99
bogdanm 15:4892fe388435 100 static inline uint32_t adc_read_u32(analogin_t *obj) {
bogdanm 15:4892fe388435 101 uint32_t value;
bogdanm 15:4892fe388435 102 #if ANALOGIN_MEDIAN_FILTER
bogdanm 15:4892fe388435 103 uint32_t v1 = adc_read(obj);
bogdanm 15:4892fe388435 104 uint32_t v2 = adc_read(obj);
bogdanm 15:4892fe388435 105 uint32_t v3 = adc_read(obj);
bogdanm 15:4892fe388435 106 order(&v1, &v2);
bogdanm 15:4892fe388435 107 order(&v2, &v3);
bogdanm 15:4892fe388435 108 order(&v1, &v2);
bogdanm 15:4892fe388435 109 value = v2;
bogdanm 15:4892fe388435 110 #else
bogdanm 15:4892fe388435 111 value = adc_read(obj);
bogdanm 15:4892fe388435 112 #endif
bogdanm 15:4892fe388435 113 return value;
bogdanm 15:4892fe388435 114 }
bogdanm 15:4892fe388435 115
bogdanm 15:4892fe388435 116 uint16_t analogin_read_u16(analogin_t *obj) {
bogdanm 15:4892fe388435 117 uint32_t value = adc_read_u32(obj);
bogdanm 15:4892fe388435 118
bogdanm 15:4892fe388435 119 return (value << 4) | ((value >> 8) & 0x000F); // 12 bit
bogdanm 15:4892fe388435 120 }
bogdanm 15:4892fe388435 121
bogdanm 15:4892fe388435 122 float analogin_read(analogin_t *obj) {
bogdanm 15:4892fe388435 123 uint32_t value = adc_read_u32(obj);
bogdanm 15:4892fe388435 124 return (float)value * (1.0f / (float)ADC_RANGE);
bogdanm 15:4892fe388435 125 }