AnsweredAssumed Answered

Random using ADC

Question asked by Zuzzuz on Oct 12, 2012
Latest reply on Oct 15, 2012 by Zuzzuz
Hi, i try to do an elettronic dice with stm32vldiscovery.
I want use 2 value read from adc i try to use this to process my data
m_w = <choose-initializer>;    /* must not be zero */
 m_z = <choose-initializer>;    /* must not be zero */
 uint get_random()
     {
          m_z = 36969 * (m_z & 65535) + (m_z >> 16);
           m_w = 18000 * (m_w & 65535) + (m_w >> 16);
           return (m_z << 16) + m_w;  /* 32-bit result */
       }
where m_z and m_w are 2 random value read from adc.
i used this code for adc
#include "stm32f10x.h"
#include "random.h"
#include "stm32f10x_adc.h"
#include "stm32f10x_dma.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define ADC1_DR_Address    ((uint32_t)0x4001244C)
  
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
ADC_InitTypeDef ADC_InitStructure;
DMA_InitTypeDef DMA_InitStructure;
__IO uint16_t ADCConvertedValue;
  
/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void GPIO_Configuration(void);
  
/* Private functions ---------------------------------------------------------*/
void prova (void)
{
  
  /*!< At this stage the microcontroller clock setting is already configured, 
       this is done through SystemInit() function which is called from startup
       file (startup_stm32f10x_xx.s) before to branch to application main.
       To reconfigure the default setting of SystemInit() function, refer to
       system_stm32f10x.c file
     */     
         
  /* System clocks configuration ---------------------------------------------*/
  RCC_Configuration();
  
  /* GPIO configuration ------------------------------------------------------*/
  GPIO_Configuration();
  
  /* DMA1 channel1 configuration ----------------------------------------------*/
  DMA_DeInit(DMA1_Channel1);
  DMA_InitStructure.DMA_PeripheralBaseAddr = ADC1_DR_Address;
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)&ADCConvertedValue;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
  DMA_InitStructure.DMA_BufferSize = 1;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  DMA_Init(DMA1_Channel1, &DMA_InitStructure);
    
  /* Enable DMA1 channel1 */
  DMA_Cmd(DMA1_Channel1, ENABLE);
    
  /* ADC1 configuration ------------------------------------------------------*/
  ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
  ADC_InitStructure.ADC_ScanConvMode = ENABLE;
  ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
  ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_NbrOfChannel = 1;
  ADC_Init(ADC1, &ADC_InitStructure);
  
  /* ADC1 regular channel14 configuration */ 
    ADC_RegularChannelConfig(ADC1, ADC_Channel_10,1, ADC_SampleTime_55Cycles5);
          
  /* Enable ADC1 DMA */
  ADC_DMACmd(ADC1, ENABLE);
    
  /* Enable ADC1 */
  ADC_Cmd(ADC1, ENABLE);
  
  /* Enable ADC1 reset calibration register */   
  ADC_ResetCalibration(ADC1);
  /* Check the end of ADC1 reset calibration register */
  while(ADC_GetResetCalibrationStatus(ADC1));
  
  /* Start ADC1 calibration */
  ADC_StartCalibration(ADC1);
  /* Check the end of ADC1 calibration */
  while(ADC_GetCalibrationStatus(ADC1));
       
  /* Start ADC1 Software Conversion */ 
  ADC_SoftwareStartConvCmd(ADC1, ENABLE);
    
    
    
  
uint32_t m_z = ADCConvertedValue ;   /* must not be zero */
uint32_t m_w = ADCConvertedValue;    /* must not be zero */
m_z = 36969 * (m_z & 65535) + (m_z >> 16);
m_w = 18000 * (m_w & 65535) + (m_w >> 16);
int caso = ((m_z << 16) + m_w) <<   31;
  
  
    
  
}
  
  
  
/**
  * @brief  Configures the different system clocks.
  * @param  None
  * @retval None
  */
void RCC_Configuration(void)
{
#if defined (STM32F10X_LD_VL) || defined (STM32F10X_MD_VL) || defined (STM32F10X_HD_VL)
  /* ADCCLK = PCLK2/2 */
  RCC_ADCCLKConfig(RCC_PCLK2_Div2); 
#else
  /* ADCCLK = PCLK2/4 */
  RCC_ADCCLKConfig(RCC_PCLK2_Div4); 
#endif
  /* Enable peripheral clocks ------------------------------------------------*/
  /* Enable DMA1 clock */
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
  
  /* Enable ADC1 and GPIOC clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_GPIOC, ENABLE);
}
  
/**
  * @brief  Configures the different GPIO ports.
  * @param  None
  * @retval None
  */
void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  
  /* Configure PC.04 (ADC Channel14) as analog input -------------------------*/
  
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
  GPIO_Init(GPIOC, &GPIO_InitStructure);
}

Adc work good cause in debug i can see how change ADCConvertedValue in realtime, but m_w and m_z give me an error and no value comes back.
I think i can't assign good the value from adc to my variable, someone can help me? thx.

Outcomes