ADC Simple

/**
  *****************************************************************************
  * @title   ADC_simple.c
  * @author  Claude
  * @date    19 Jul 2012
  * @brief
  *******************************************************************************
  */
////// The above comment is automatically generated by CoIDE ///////////////////

/**
  *****************************************************************************
  * @title   ADC_simple.c
  * @author  Claude
  * @date    2010 Dec 29
  * @brief   ADC Example, Blink a LED according to ADC value
  *******************************************************************************
  */

#include<stm32f10x_rcc.h>
#include<stm32f10x_gpio.h>
#include<stm32f10x_adc.h>

#include "stm32f10x.h"
#include "stm32f10x_conf.h"

GPIO_InitTypeDef GPIO_InitStructure;
ADC_InitTypeDef ADC_InitStructure;
int i,j;

/* Blink a LED, blink speed is set by ADC value */
void ADC_simple(void)
{
// init for GPIO (LED)
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_8 | GPIO_Pin_9 ;   // two LED (guess on what pin!!)
    GPIO_Init(GPIOB, &GPIO_InitStructure);

// input of ADC (it doesn't seem to be needed, as default GPIO state is floating input)
    GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AIN;
    GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_1 ;        // that's ADC1 (PA1 on STM32)
    GPIO_Init(GPIOA, &GPIO_InitStructure);

//clock for ADC (max 14MHz --> 72/6=12MHz)
    RCC_ADCCLKConfig (RCC_PCLK2_Div6);
// enable ADC system clock
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);

// define ADC config
    ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
    ADC_InitStructure.ADC_ScanConvMode = DISABLE;
    ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;  // we work in continuous sampling mode
    ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
    ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
    ADC_InitStructure.ADC_NbrOfChannel = 1;

    ADC_RegularChannelConfig(ADC1,ADC_Channel_1, 1,ADC_SampleTime_28Cycles5); // define regular conversion config
    ADC_Init ( ADC1, &ADC_InitStructure);   //set config of ADC1

// enable ADC
    ADC_Cmd (ADC1,ENABLE);  //enable ADC1

//  ADC calibration (optional, but recommended at power on)
    ADC_ResetCalibration(ADC1); // Reset previous calibration
    while(ADC_GetResetCalibrationStatus(ADC1));
    ADC_StartCalibration(ADC1); // Start new calibration (ADC must be off at that time)
    while(ADC_GetCalibrationStatus(ADC1));

// start conversion
    ADC_Cmd (ADC1,ENABLE);  //enable ADC1
    ADC_SoftwareStartConvCmd(ADC1, ENABLE); // start conversion (will be endless as we are in continuous mode)

// debug information
    RCC_ClocksTypeDef forTestOnly;
    RCC_GetClocksFreq(&forTestOnly);    //this could be used with debug to check to real speed of ADC clock

    j= 50000;
    while(1)
    {
        GPIO_WriteBit(GPIOB,GPIO_Pin_8,Bit_RESET);
        GPIO_WriteBit(GPIOB,GPIO_Pin_9,Bit_SET);
        for (i=0;i<j;i++);
        GPIO_WriteBit(GPIOB,GPIO_Pin_9,Bit_RESET);
        GPIO_WriteBit(GPIOB,GPIO_Pin_8,Bit_SET);

        // adc is in free run, and we get the value asynchronously, this is not a really nice way of doing, but it work!
        j = ADC_GetConversionValue(ADC1) * 1000 ; // value from 0 to 4095000
        for (i=0;i<j;i++);
    }
    /* possible change :
     * ADC_ContinuousConvMode = DISABLE
     * then on the infinite loop, something like :
     *
     *  ADC_SoftwareStartConvCmd(ADC1, ENABLE);                 // start ONE conversion
     *  while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET);  // wait end of conversion
     *  j = ADC_GetConversionValue(ADC1) * 500;                 // get value
     *
     */
}