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When does ADC/DMA actually stop?

Question asked by parsec67 on Jan 5, 2017

In my project (F415RG) I'm running timer paced single channel ADC sampling with DMA transfers and Analog Watchdog coupled to the same ADC channel. When an out of window voltage occur I need to momentarily stop the ADC in the associated callback function but I'm not clear on if calling HAL_ADC_Stop_DMA() is instantaneous or if it keeps sampling until current buffer is Transfer Complete? I guess some extra samples after a halt is requested are unavoidable due to its CPU independent operation but are there any hard or approximate figures on how much this will be?


While I'm at it, a vaguely related question; Should global variables in any HAL_ADC_...() callback functions be declared volatile?