AnsweredAssumed Answered

when use uart with DMA, why its DMA callback function invoked so slowly?

Question asked by aaron gao on Dec 7, 2015
Latest reply on Dec 22, 2015 by Yuri Muhin

The follow issue i have deal with it for a long time, but i cannot complete it.

 

Description: On imx6sx i send the packet which is about 6 bytes and then, after sending over, I  send next packet about 2ms later. The amazing things happened, the tx interrupt is triggered, but the dma callback is invoked 4ms later, that is to say, the date will be sent out almostly 4ms after tx interrupt.

 

and the following packets are the same as above, if i increase the send interval, it will be ok. and tx interrupt is triggered, the tx callback will be invoked immediately.

 

I am looking forward to your reply, thank you very much at first.

tx_callback prompt.png

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