Garbage values while using multiple ADC channels

[RJain.1]

Hi,

I am using STM32H743 Nucleo to interface 9 analog sensors on different ADC channels of ADC1. ADC1 is configured as:

hadc1.Instance = ADC1;

 hadc1.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV6;

 hadc1.Init.Resolution = ADC_RESOLUTION_16B;

 hadc1.Init.ScanConvMode = ADC_SCAN_ENABLE;

 hadc1.Init.EOCSelection = ADC_EOC_SEQ_CONV;

 hadc1.Init.LowPowerAutoWait = DISABLE;

 hadc1.Init.ContinuousConvMode = DISABLE;

 hadc1.Init.NbrOfConversion = 9;

 hadc1.Init.DiscontinuousConvMode = ENABLE;

 hadc1.Init.ExternalTrigConv = ADC_EXTERNALTRIG_T1_TRGO;

 hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_RISING;

 hadc1.Init.ConversionDataManagement = ADC_CONVERSIONDATA_DMA_CIRCULAR;

 hadc1.Init.Overrun = ADC_OVR_DATA_PRESERVED;

 hadc1.Init.LeftBitShift = ADC_LEFTBITSHIFT_NONE;

 hadc1.Init.OversamplingMode = DISABLE;

uint16_t adc_op[9];

In Main:

 if (HAL_ADC_Start_DMA(&hadc1,(uint32_t *)adc_op, sizeof(adc_op) ) != HAL_OK)

 {

 Error_Handler();

 }

 if (HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1) != HAL_OK){

 Error_Handler();

 }

When I am connecting a sensor on Channel 10, some garbage data is reflected on other channels too.

I am unable to debug the problem.\

Please help.

Thanks,

[FBL]

Hello @RJain.1​,

To identify the source of interference, disconnect sensors. Then, you can proceed by adding and testing sensors one by one.

According to AN2834, you may need to check section 3.2 Errors due to the ADC environment for better details about the root cause.

You can find out as well how to reduce their effects.

Hope this helps!