reading multiple adc channels, no dma

Posted on January 26, 2015 at 11:58

Hello List,

I,m struggling with reading, without DMA, from multiple channels. Every, say, 10 msec I call:

var1 = Get_ADC_Value(11);
var2 = Get_ADC_Value(12);

Both variables ALWAYS get the same value, that is the value from the first called channel, here The function (partly) is:

int16_t Get_ADC_Value(uint8_t Channel)
{
uint16_t ADC_Val; //Stores the calculated ADC value
switch(Channel)
{
case 11:
ADC_RegularChannelConfig(ADC1, ADC_Channel_11, 1, ADC_SampleTime_84Cycles);
ADC_SoftwareStartConv(ADC1);
while(ADC_GetSoftwareStartConvStatus(ADC1) != RESET){ADC_Val = 0;}
ADC_Val = ADC_GetConversionValue(ADC1);
break;
case 12:
ADC_RegularChannelConfig(ADC1, ADC_Channel_12, 1, ADC_SampleTime_84Cycles);
ADC_SoftwareStartConv(ADC1);
while(ADC_GetSoftwareStartConvStatus(ADC1) != RESET){ADC_Val = 0;}
ADC_Val = ADC_GetConversionValue(ADC1);
break;
.... other channels

The configuration:

void ADC_Configuration(void)
{
ADC_InitTypeDef ADC_InitStructure;
ADC_CommonInitTypeDef ADC_CommonInitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
/* Configure ADC Channel 11, 12, 15, and 14 as analog input */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_5 | GPIO_Pin_4;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
GPIO_Init(GPIOC, &GPIO_InitStructure);
/* ADC Common configuration *************************************************/
ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div2;
ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled;
ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;
ADC_CommonInit(&ADC_CommonInitStructure);
/* ADC1 regular channel 10 to 15 configuration ************************************/
ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
ADC_InitStructure.ADC_ScanConvMode = DISABLE;
ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfConversion = 1;
ADC_Init(ADC1, &ADC_InitStructure);
ADC_Init(ADC2, &ADC_InitStructure);
/* Enable ADC1 to ADC3*/
ADC_Cmd(ADC1, ENABLE);
ADC_Cmd(ADC2, ENABLE);
}

Clocks are also enabled. All in all completely standard, but .... Hopefully someone can help me. Thanks in advance, Sietse #stm32f4-adc-multichannel