Is it possible to use a DMA on SWO ?

[root]

Posted on October 02, 2012 at 21:46

Hello,

Everything is in the title, is it possible to use a DMA to transmit data on SWO ? Or at least to send data (multiple bytes) without blocking execution ?

Thomas.

#itm-dma-jtag

[jpeacock2399]

Posted on October 03, 2012 at 16:00

You can always do a memory to memory DMA, but you would have to come up with some way to ensure the ITM queue has space for the DMA transfer.  Given the relatively high data rate of ITM (I get 2Mbit/sec with an STM32F205 at 120MHz using J-Link SWO Viewer) it might be safe to use a timer to trigger a DMA transfer.

  Jack Peacock

[Tesla DeLorean]

Posted on October 03, 2012 at 16:09

It would depend if the core registers have in-bound access via the AHB, somehow I imagine they'd be like TCM/CCM and be unavailable to DMA.

As Jack suggest pace it with a timer, it'll either work or not, but I wouldn't spend a lot of time fighting with it.