MB1034B STM32F0DISCOVERY Problems on ADC multichannel

[matteo239955_st]

Posted on September 10, 2012 at 11:10

I've a problems to use the multiplexer on analog channel:

this is my init procedure:typedef enum{    ADC_VCH,    ADC_TEMP,    ADC_REF,    NofAnalogIn} t_AnalogIn;unsigned short ACDValue[NofAnalogIn];&sharpdefine RCC_PORT_AIN_VCH RCC_AHBPeriph_GPIOA&sharpdefine GPIO_PORT_AIN_VCH GPIOA&sharpdefine GPIO_PIN_AIN_VCH GPIO_Pin_1&sharpdefine RCC_ADC_AIN_VCH RCC_APB2Periph_ADC1&sharpdefine ADC_CHANNEL_VCH ADC_Channel_1&sharpdefine RCC_PORT_AIN_TEMP RCC_AHBPeriph_GPIOA&sharpdefine GPIO_PORT_AIN_TEMP GPIOA&sharpdefine GPIO_PIN_AIN_TEMP GPIO_Pin_2&sharpdefine RCC_ADC_AIN_TEMP RCC_APB2Periph_ADC1&sharpdefine ADC_CHANNEL_TEMP ADC_Channel_2&sharpdefine RCC_PORT_AIN_REF RCC_AHBPeriph_GPIOA&sharpdefine GPIO_PORT_AIN_REF GPIOA&sharpdefine GPIO_PIN_AIN_REF GPIO_Pin_3&sharpdefine RCC_ADC_AIN_REF RCC_APB2Periph_ADC1&sharpdefine ADC_CHANNEL_REF ADC_Channel_3unsigned char InitAnalog(void) { ADC_InitTypeDef     ADC_InitStructure;GPIO_InitTypeDef    GPIO_InitStructure;   /* GPIOC Periph clock enable */  RCC_AHBPeriphClockCmd(RCC_PORT_AIN_VCH | RCC_PORT_AIN_TEMP | RCC_PORT_AIN_REF, ENABLE);    /* ADC1 Periph clock enable */  RCC_APB2PeriphClockCmd(RCC_ADC_AIN_VCH | RCC_ADC_AIN_TEMP | RCC_ADC_AIN_REF, ENABLE);    /* Configure ADC VCH as analog input */  GPIO_InitStructure.GPIO_Pin = GPIO_PIN_AIN_VCH ;  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;  GPIO_Init(GPIO_PORT_AIN_VCH, &GPIO_InitStructure);  /* Configure ADC TEMP as analog input */  GPIO_InitStructure.GPIO_Pin = GPIO_PIN_AIN_TEMP ;  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;  GPIO_Init(GPIO_PORT_AIN_TEMP, &GPIO_InitStructure);  /* Configure ADC REF as analog input */  GPIO_InitStructure.GPIO_Pin = GPIO_PIN_AIN_REF ;  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;  GPIO_Init(GPIO_PORT_AIN_REF, &GPIO_InitStructure);    /* ADCs DeInit */    ADC_DeInit(ADC1);    /* Initialize ADC structure */  ADC_StructInit(&ADC_InitStructure);    /* Configure the ADC1 in continous mode withe a resolutuion equal to 12 bits  */  ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;  ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;   ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;  ADC_InitStructure.ADC_ScanDirection = ADC_ScanDirection_Upward;  ADC_Init(ADC1, &ADC_InitStructure); /* ADC Calibration */  if (ADC_GetCalibrationFactor(ADC1) == 0)  return 0;    /* Enable ADCperipheral[PerIdx] */  ADC_Cmd(ADC1, ENABLE);  /* Wait the ADCEN falg */  while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_ADEN));     return 1;}unsigned short APS_GetTemp(void){ /* ADC1 regular Software Start Conv */  ADC_ChannelConfig(ADC1, ADC_CHANNEL_TEMP , ADC_SampleTime_239_5Cycles);   // Start the conversion  ADC_StartOfConversion(ADC1);/* Test EOC flag */  while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET);  /* Get ADC1 converted data */  ACDValue[ADC_TEMP] =ADC_GetConversionValue(ADC1);      return ACDValue[ADC_TEMP];}unsigned short APS_GetVCH(void){   ADC_ChannelConfig(ADC1, ADC_CHANNEL_VCH , ADC_SampleTime_239_5Cycles);   /* ADC1 regular Software Start Conv */   ADC_StartOfConversion(ADC1);/* Test EOC flag */  while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET);/* Get ADC1 converted data */  ACDValue[ADC_VCH] =ADC_GetConversionValue(ADC1);    return ACDValue[ADC_VCH];}On Pa2 I've 1,45 VoltOn PA1 I've 2,28 VoltWhen I call the two function APS_GetVCH and APS_GetTemp some time I see 3000 - 1800 If I call GetVCH before GetTemp, but if I call GetTemp Before I see 1800 - 3000 ????  What's wrong in my code? #adc-smt32-f0

[raptorhal2]

Posted on September 11, 2012 at 02:53

What's wrong in my code?

Perhaps nothing. VCH is PA1 and has the higher input voltage, so all is well as far as I can tell. Regards, Hal

[matteo239955_st]

Posted on September 11, 2012 at 08:23

I'm sorry for my english..

if I call APS_GetVCH();APS_GetTemp();ACDValue[0] -> 3000ADCValue[1] -> 1800if I invert the order of call like APS_GetTemp();APS_GetVCH();ACDValue[0] -> 1800ADCValue[1] -> 3000there is something wrong on the multiplexer or timing but I don't know how can be solved..Is it more clear, Hal?

[raptorhal2]

Posted on September 11, 2012 at 17:13

Perhaps the AnalogIn structure is not initialized.

You have two copies of unsigned short APS_GetTemp(void){. Is that just a copy/paste to forum oversight? Cheers, Hal

[matteo239955_st]

Posted on September 11, 2012 at 17:34Do you mean this?

  /* Initialize ADC structure */

  ADC_StructInit(&ADC_InitStructure);

[raptorhal2]

Posted on September 11, 2012 at 21:10

No, I mean this:

typedef enum{     ADC_VCH,     ADC_TEMP,     ADC_REF,     NofAnalogIn } t_AnalogIn; Cheers, Hal

[matteo239955_st]

Posted on September 12, 2012 at 11:02

It's an enum 0,1,2,3,4 ecc...

[raptorhal2]

Posted on September 13, 2012 at 01:27

You are right, I am wrong.

Other than not running the ADC continuously, you are following the F0 library basic ADC example code. I can't spot any problem and I don't have an F0 to try your code on. My suggestion is to step through the code and make sure that items like ADC_TEMP and the converted values are what you expect. Possibly someone else can spot something. Cheers, Hal