Use ADC1's 2 Channel Problem

leventeyigel52 · ‎2012-08-01

Posted on August 01, 2012 at 10:34

uint16_t Read_OPTOLed_ADC1(void)

{

ADC_RegularChannelConfig(ADC1, ADC_Channel_14, 1, ADC_SampleTime_71Cycles5);

ADC_SoftwareStartConvCmd(ADC1, ENABLE);

while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET); // Get the conversion value

OptoLedArray = ADC_GetConversionValue(ADC1);

// return ADC_GetConversionValue(ADC1);

}

uint16_t Read_TEMP_ADC1(void)

{

ADC_RegularChannelConfig(ADC1, ADC_Channel_7, 1, ADC_SampleTime_71Cycles5);

while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET); // Get the conversion value

TempArray = ADC_GetConversionValue(ADC1);

// return ADC_GetConversionValue(ADC1);

}

The ADC Configuration

void ADC_Configuration (void)

{

ADC_InitTypeDef ADC_InitStructure;

GPIO_InitTypeDef GPIO_InitStructure;

RCC_APB2PeriphClockCmd( RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOC|

RCC_APB2Periph_ADC1, ENABLE);

///////////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////

/* Configure PC4 (ADC Channel 7) as analog input -------------------------*/

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;

GPIO_Init(GPIOA, &GPIO_InitStructure);

/* Configure PA7 (ADC Channel 14) as analog input -------------------------*/

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;

GPIO_Init(GPIOC, &GPIO_InitStructure);

/* ADC1 configuration ------------------------------------------------------*/

ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;

ADC_InitStructure.ADC_ScanConvMode = ENABLE;

ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;

ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;

ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;

ADC_InitStructure.ADC_NbrOfChannel = 2;

ADC_Init(ADC1, &ADC_InitStructure);

/* Enable ADC1 */

ADC_Cmd(ADC1, ENABLE);

/* Enable ADC1 reset calibaration register */

ADC_ResetCalibration(ADC1);

/* Check the end of ADC1 reset calibration register */

while(ADC_GetResetCalibrationStatus(ADC1));

/* Start ADC1 calibaration */

ADC_StartCalibration(ADC1);

/* Check the end of ADC1 calibration */

while(ADC_GetCalibrationStatus(ADC1));

/* Start ADC1 Software Conversion */

ADC_SoftwareStartConvCmd(ADC1, ENABLE);

}

PC.4 is ADC Channel 14 , PA.7 ADC Channel 7 ( Stm32 C-Eval )

I want to see this channels' ADC Values but i see the same values at the same time.

Do i mistake at the configuration or ReadADC Function ?

raptorhal2 · ‎2012-08-01

Posted on August 01, 2012 at 15:32

The ADC conversion register holds only one value. Change the initialization to:

ADC_InitStructure.ADC_NbrOfChannel = 1;

To convert two or more channels with one start conversion command, DMA is required. You are using two start conversions, which works also.

Cheers, Hal

leventeyigel52 · ‎2012-08-01

Posted on August 01, 2012 at 15:58

How can i add DMA for this configuration without interrupt ?

raptorhal2 · ‎2012-08-01

Posted on August 01, 2012 at 17:15

Poll the DMA current data counter. When = 0, all channels are converted and in the assigned buffer.

See the Standard Peripheral Library example for ADC DMA to get started.

Cheers, Hal