ADC STM32F013RE Default is HIGH (4059 )!

[ssabz]

I have written some codes to work with ADC Of STM32F103RE MCU, the problem is there which when I write this codes the result is 4059 for untouched and around 3585 when touched.

The Codes:

 void ADC_DMA_init(void) {
 
 //enable DMA1 clock
 
 RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
 
 //create DMA structure
 
 DMA_InitTypeDef DMA_InitStructure;
 
 //reset DMA1 channe1 to default values;
 
 DMA_DeInit(DMA1_Channel1);
 
 //channel will be used for memory to memory transfer
 
 DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
 
 //setting normal mode (non circular)
 
 DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
 
 //medium priority
 
 DMA_InitStructure.DMA_Priority = DMA_Priority_High;
 
 //source and destination data size word=32bit
 
 DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
 
 DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
 
 //automatic memory destination increment enable.
 
 DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
 
 //source address increment disable
 
 DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
 
 //Location assigned to peripheral register will be source
 
 DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
 
 //chunk of data to be transfered
 
 DMA_InitStructure.DMA_BufferSize = 2;
 
 //source and destination start addresses
 
 DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&ADC1->DR;;
 
 //adc values is: volatile uint16_t ADC_values[ARRAYSIZE];
 
 DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)&ADC1ConvertedValue; 
 
 //send values to DMA registers
 
 DMA_Init(DMA1_Channel1, &DMA_InitStructure);
 
 // Enable DMA1 Channel Transfer Complete interrupt
 
 DMA_ITConfig(DMA1_Channel1, DMA_IT_TC, ENABLE);
 
 DMA_Cmd(DMA1_Channel1, ENABLE); //Enable the DMA1 - Channel1
 
 }
 
 
 uint16_t Get_ADC_Converted_Value()//int Get_ADC_Converted_Value()
 
 {
 
 ADC_SoftwareStartConvCmd(ADC1, ENABLE);
 
 while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC))
 
 {
 
 return ADC_GetConversionValue(ADC1);
 
 }
 
 }
 
 /**
 
 * Initialization of ADC and the poentiomenter's GPIO
 
 */
 
 uint16_t badprogADC() {
 
 /// declaring GPIO stuff
 
 GPIO_InitTypeDef GPIO_InitStructure;
 
 // declaring ADC struct
 
 ADC_InitTypeDef ADC_InitStructure;
 
 
 
 
 // deinit ADC
 
 ADC_DeInit(ADC1);
 
 
 // enabling clock
 
 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
 
 // enabling ADC clock
 
 RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
 
 
 // B - Init the GPIO with the structure - Testing ADC
 
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
 
 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
 
 //GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
 
 GPIO_InitStructure.GPIO_Mode =GPIO_Mode_AIN;
 
 //GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;//The pins are configured in analog mode
 
 
 GPIO_Init(GPIOB, &GPIO_InitStructure);
 
 //GPIO_ResetBits(GPIOB,GPIO_Pin_7);
 
 //GPIO_ResetBits(GPIOB,GPIO_Pin_6);
 
 
 // init ADC struct
 
 ADC_StructInit(&ADC_InitStructure);
 
 
 // setting the ADC struct
 
 ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
 
 ADC_InitStructure.ADC_ScanConvMode = DISABLE;
 
 ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
 
 ADC_InitStructure.ADC_ExternalTrigConv = 0;//ADC_ExternalTrigConv_None;
 
 ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
 
 ADC_InitStructure.ADC_NbrOfChannel = 2;
 
 
 ADC_DMA_init();
 
 
 
 // init adc
 
 ADC_Init(ADC1, &ADC_InitStructure);
 
 
 // enable ADC
 
 ADC_Cmd(ADC1, ENABLE);
 
 
 
 ADC_DMACmd(ADC1, DISABLE); 
 
 /* Enable DMA mode for ADC1 */ 
 
 ADC_DMACmd(ADC1, ENABLE);
 
 
 
 // start ADC1 calibration and check the end
 
 ADC_StartCalibration(ADC1);
 
 
 // configure ADC_IN6
 
 ADC_RegularChannelConfig(ADC1, ADC_Channel_6, 1, ADC_SampleTime_7Cycles5);
 
 ADC_RegularChannelConfig(ADC1, ADC_Channel_7, 1, ADC_SampleTime_7Cycles5); ///added
 
 
 // start ADC -> retrieve the ADC value from the potentiometer
 
 // and add it into ADC1->DR with:
 
 // ADCx->CR2 |= CR2_EXTTRIG_SWSTART_Set;
 
 // this without using ADC1->DR o_O
 
 // CR2 = Configuration Register2 -> it seems to be a config with
 
 // a binary number -> for example 1000010100101010 which sets all
 
 // registers with default values
 
 ADC_SoftwareStartConvCmd(ADC1, ENABLE);
 
 // Make sure we have conversion completion
 
 while( ADC_GetFlagStatus( ADC1, ADC_FLAG_EOC ) == RESET )
 
 {
 
 // do nothing (or something useful perhaps)
 
 }
 
 // Wait until ADC is ready
 
 //while (ADC_GetFlagStatus(ADC1, ADC_FLAG_ADONS) == RESET);
 
 // check the end of the ADC1 calibration
 
 // setting ADC1->DR with:
 
 // if ((ADCx->CR2 & CR2_CAL_Set) != (uint32_t)RESET)
 
 while (ADC_GetCalibrationStatus(ADC1) == SET);
 
 
 // Reset the flag
 
 ADC_ClearFlag(ADC1, ADC_FLAG_EOC);
 
 
 // convert valueADC to valueVolt -> valueADC * (MAX VOLT / 2^12)
 
 // and also :
 
 // ADC_SoftwareStartConvCmdsoftwareS,
 
 // ADC_GetCalibrationStatus
 
 // with
 
 // return (uint16_t) ADCx->DR;
 
 uint16_t valueADC = ADC_GetConversionValue(ADC1);
 
 
 // convert the "uint_16 valueADC" into a "float valueVolt"
 
 // Volt = 3.3
 
 // ADC = 12 bits, so 2^12 = 4096
 
 float valueVolt = valueADC * (3.3 / 4095);
 
 
 //return valueVolt;
 
 //return ADC_GetConversionValue(ADC1);
 
 return ADC1ConvertedValue[0];
 
 //return Get_ADC_Converted_Value();
 
 }

And by changing the two last line of codes to this kind:

      

//return ADC1ConvertedValue[0];
 
 return Get_ADC_Converted_Value();

Touch shown 0 for untouched and around 3940 for touched.

Some part of main function is shown Below:

   

while (1) {
 		GUI_Clear();
 		GUI_SetBkColor(GUI_BLACK);
 		GUI_SetColor(GUI_CYAN);
 	sprintf(buffer, "%d\r\n", (int) TouchScreen_readPressure());GUI_Delay(300);
 		// GUI_Init(); GUI_Delay(300);
 	GUI_DispStringHCenterAt(buffer, xSize / 3, ySize - 111);	GUI_Delay(300);
 		GUI_DispStringAt("GUI_DispFloat:\n", 11, 11);
 		GUI_GotoX(100);
 		GUI_GotoY(100);
 		//f=(float) TouchScreen_readPressure();
 		//GUI_DispFloat(f,9);
 	GUI_Delay(300);
 	}

So why this happended?

 this question in stackowerflow:

https://electronics.stackexchange.com/questions/424898/adc-stm32f013re-default-is-high-4059

Thanks