In software for Y point for averaging of each channel, request HAL_ADC_Start_DMA with X*Y point; When you want to read a channel known point in memory, without checking ADC status. In the picture, ...

HAL_ADC_PollForConversion is used to obtain the ADC reading. Here the CPU waits for the sampling and conversion process inside the microcontroller ADC unit. This is the simplest implementation useful ...