File content as of revision 390:35c2c1cf29cd:

/* mbed Microcontroller Library
 * Copyright (c) 2006-2013 ARM Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "mbed_assert.h"
#include "analogin_api.h"

#include "cmsis.h"
#include "pinmap.h"

#include "adc_iodefine.h"
#include "cpg_iodefine.h"

#define ANALOGIN_MEDIAN_FILTER      1

#define ADC_12BIT_RANGE             0xFFF

static const PinMap PinMap_ADC[] = {
    {P1_8,  AN0, 1},
    {P1_9,  AN1, 1},
    {P1_10, AN2, 1},
    {P1_11, AN3, 1},
    {P1_13, AN5, 1},
    {P1_15, AN7, 1},
    {NC,    NC,     0}
};

static volatile uint16_t *ADCDR[] = {
    &ADCADDRA,
    &ADCADDRB,
    &ADCADDRC,
    &ADCADDRD,
    &ADCADDRE,
    &ADCADDRF,
    &ADCADDRG,
    &ADCADDRH,
};

#define ADC_RANGE    ADC_12BIT_RANGE

void analogin_init(analogin_t *obj, PinName pin) {
    obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
    MBED_ASSERT(obj->adc != (ADCName)NC);
    
    CPGSTBCR3 &= ~(1 << 1);
    CPGSTBCR6 &= ~(1 << 7);

    // 000_0 000_1 11_00 0_xxx
    // 15: ADFlag 14: IntEn 13: start, [12:9] Triger..0
    //    [8:6] CLK 100 :: 12-bit 1054tclk
    //    [5:3] scanmode 000 :: single mode
    //    [2:0] channel select
    ADCADCSR = 0x0100 | (obj->adc&0xf);
    
    pinmap_pinout(pin, PinMap_ADC);
}

static inline uint32_t adc_read(analogin_t *obj) {
    // Select the appropriate channel and start conversion
    ADCADCSR |= (1 << 13 | (obj->adc&0xf));
    
    // Repeatedly get the sample data until DONE bit
#define nothing
    while ((ADCADCSR & (1 << 15)) == 0 || (ADCADCSR & (1<<13)) != 0) nothing;
    
    // clear flag
    ADCADCSR &= ~(1 << 15);
    
    return ((*(ADCDR[obj->adc]))>>4) & ADC_RANGE; // 12 bit
}

static inline void order(uint32_t *a, uint32_t *b) {
    if (*a > *b) {
        uint32_t t = *a;
        *a = *b;
        *b = t;
    }
}

static inline uint32_t adc_read_u32(analogin_t *obj) {
    uint32_t value;
#if ANALOGIN_MEDIAN_FILTER
    uint32_t v1 = adc_read(obj);
    uint32_t v2 = adc_read(obj);
    uint32_t v3 = adc_read(obj);
    order(&v1, &v2);
    order(&v2, &v3);
    order(&v1, &v2);
    value = v2;
#else
    value = adc_read(obj);
#endif
    return value;
}

uint16_t analogin_read_u16(analogin_t *obj) {
    uint32_t value = adc_read_u32(obj);
    
    return value;
    //(value << 4) | ((value >> 8) & 0x000F); // 12 bit
}

float analogin_read(analogin_t *obj) {
    uint32_t value = adc_read_u32(obj);
    return (float)value * (1.0f / (float)ADC_RANGE);
}