STM32 and DMA transfer

kornfeldner · ‎2009-11-13

Posted on November 13, 2009 at 10:59

kornfeldner · ‎2011-05-17

Posted on May 17, 2011 at 13:29

when i start tow DMA channles transer, for example with 300Bytes data to transfer. is it possible to start another high priority DMA which interrupts the current onging tranfers ?

i made a example and it looks like it is possible but the application AN2548 says:

''While a channel is being served (operation 2 or 3 ongoing), no other

channel can be served whatever its priority.''

do this mean when i transfer 300Bytes the DMA controller is blocked ?

tomas23 · ‎2011-05-17

Posted on May 17, 2011 at 13:29

The ''operation 2 and 3'' is related to the running DMA transfer (single read from source and single write to destination). Once this single transfer is completed, another arbitration starts.

The DMAs do not support burst mode, so they cannot block the AHB nor another DMa channels for longer time.