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Switching pin between ADC and General IO

Question asked by ebommer on Apr 9, 2014
Latest reply on Apr 9, 2014 by ebommer
Hi All,


What I would like to do is when I receive a CAN bus message with data equal to "12" I will configure GPIOB Pin 0 to an Analog input, and when the data is 11 it will be reconfigured to an General purpose I/O. 


#define ADC1_DR_Address    ((uint32_t)0x4001244C)

__IO uint16_t ADCConvertedValue[5];  

void Port_Config(void)
{
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); 
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_GPIOA| RCC_APB2Periph_GPIOB, ENABLE);
  
/* Configure PA.0,1,2,3 as analog input -------------------------*/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_3;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

/* Configure PB.0 as Output   -------------------------*/

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;    
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  /* 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 = 4;
  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 = 4;
  ADC_Init(ADC1, &ADC_InitStructure);

  /* ADC1 regular channel 00 configuration */ 
  ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_55Cycles5);
  /* ADC1 regular channel 01 configuration */ 
  ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 2, ADC_SampleTime_55Cycles5);
  /* ADC1 regular channel 02 configuration */ 
  ADC_RegularChannelConfig(ADC1, ADC_Channel_2, 3, ADC_SampleTime_55Cycles5);
  /* ADC1 regular channel 03 configuration */ 
  ADC_RegularChannelConfig(ADC1, ADC_Channel_3, 4, 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);
}

So far in my attempts when I add an additional A/D, all of my conversions that used to work stop working.

init main(void)
{
     ......
// if(CAN message = 11,  GPIOB Pin 0 conf. as an General Purpose I/O)
 case 11:                        
 /* Configure PB0 Out On */
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
 GPIO_Init(GPIOB, &GPIO_InitStructure);
                        
 GPIO_WriteBit(GPIOB,GPIO_Pin_0,Bit_SET);
 CAN_AppTX.data[0] = 0x01;
break;
//if(CAN message = 12,  GPIOB Pin 0 configured as an analog Input)
 case 12:                        
 /* Configure PB0 A/D */                 
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
 GPIO_Init(GPIOB, &GPIO_InitStructure);

 ADC_InitStructure.ADC_NbrOfChannel = 5;
 ADC_Init(ADC1, &ADC_InitStructure);
                     
 ADC_RegularChannelConfig(ADC1, ADC_Channel_8, 5,  ADC_SampleTime_55Cycles5);

 ADC_Cmd(ADC1, ENABLE);
 ADC_SoftwareStartConvCmd(ADC1, ENABLE);
                        
 DMA_InitStructure.DMA_BufferSize = 5;
 DMA_Init(DMA1_Channel1, &DMA_InitStructure);
 DMA_Cmd(DMA1_Channel1, ENABLE);
........
}

Thank you for any help.
  

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