tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_STM/TARGET_STM32F4XX/analogin_api.c

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #include "mbed_assert.h"
  17 #include "analogin_api.h"
  18
  19 #if DEVICE_ANALOGIN
  20
  21 #include "cmsis.h"
  22 #include "pinmap.h"
  23 #include "mbed_error.h"
  24
  25 #define ADC_10BIT_RANGE             0x3FF
  26 #define ADC_12BIT_RANGE             0xFFF
  27
  28 static const PinMap PinMap_ADC[] = {
  29     {PA_0, ADC0_0,  STM_PIN_DATA(3, 0)},
  30     {PA_1, ADC0_1,  STM_PIN_DATA(3, 0)},
  31     {PA_2, ADC0_2,  STM_PIN_DATA(3, 0)},
  32     {PA_3, ADC0_3,  STM_PIN_DATA(3, 0)},
  33     {PA_4, ADC0_4,  STM_PIN_DATA(3, 0)},
  34     {PA_5, ADC0_5,  STM_PIN_DATA(3, 0)},
  35     {PA_6, ADC0_6,  STM_PIN_DATA(3, 0)},
  36     {PA_7, ADC0_7,  STM_PIN_DATA(3, 0)},
  37     {PB_0, ADC0_8,  STM_PIN_DATA(3, 0)},
  38     {PB_1, ADC0_9,  STM_PIN_DATA(3, 0)},
  39     {PC_0, ADC0_10, STM_PIN_DATA(3, 0)},
  40     {PC_1, ADC0_11, STM_PIN_DATA(3, 0)},
  41     {PC_2, ADC0_12, STM_PIN_DATA(3, 0)},
  42     {PC_3, ADC0_13, STM_PIN_DATA(3, 0)},
  43     {PC_4, ADC0_14, STM_PIN_DATA(3, 0)},
  44     {PC_5, ADC0_15, STM_PIN_DATA(3, 0)},
  45     {NC,   NC,      0}
  46 };
  47
  48 #   define ADC_RANGE    ADC_12BIT_RANGE
  49
  50 void analogin_init(analogin_t *obj, PinName pin) {
  51     obj->adc = (ADCName)pinmap_peripheral(pin, PinMap_ADC);
  52     MBED_ASSERT(obj->adc != (uint32_t)NC);
  53
  54     // ensure power is turned on
  55     RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN | RCC_AHB1ENR_GPIOBEN |
  56                     RCC_AHB1ENR_GPIOCEN;
  57     RCC->APB2ENR |= RCC_APB2ENR_ADC1EN;
  58
  59     // Enable the ADC
  60     ADC1->CR2 |= ADC_CR2_ADON;
  61
  62     pinmap_pinout(pin, PinMap_ADC);
  63 }
  64
  65 static inline uint32_t adc_read(analogin_t *obj) {
  66     // Select the appropriate channel
  67     ADC1->SQR3 = (int) obj->adc;
  68
  69     // Start conversion
  70     ADC1->CR2 |= ADC_CR2_SWSTART;
  71
  72     // Wait for conversion to finish
  73     while (!(ADC1->SR & ADC_SR_EOC));
  74
  75     uint32_t data = ADC1->DR;
  76     return data; // 12 bit
  77 }
  78
  79 static inline uint32_t adc_read_u32(analogin_t *obj) {
  80     uint32_t value;
  81     value = adc_read(obj);
  82     return value;
  83 }
  84
  85 uint16_t analogin_read_u16(analogin_t *obj) {
  86     uint32_t value = adc_read_u32(obj);
  87
  88     return (value << 4) | ((value >> 8) & 0x000F); // 12 bit
  89 }
  90
  91 float analogin_read(analogin_t *obj) {
  92     uint32_t value = adc_read_u32(obj);
  93     return (float)value * (1.0f / (float)ADC_RANGE);
  94 }
  95
  96 #endif