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Estimating DMA controller load

Question asked by SCOTT MILLER on Jul 25, 2017
Latest reply on Aug 3, 2017 by Hui_Ma

I'm making fairly heavy use of DMA in a project, considerably more than I've used in any previous project.  I have high speed (>= 1 mbps) UART traffic, I2S, DAC and ADC samples, and probably SPI a little later.


I'm curious if there are any good tools or techniques for keeping an eye on how busy the DMA controller is, and ideally also how much load is hitting the bus.


The only idea I've come up with so far would be to set up a channel with the lowest possible priority to send alternating 1s and 0s to a GPIO, where it could be monitored with a logic analyzer, the idea being that any gaps in the pattern would represent times the DMA controller was busy with higher-priority requests.


Is that reasonable?  Are there other ways to approach it?  I've done a little searching and haven't come up with anything, but I may not be using the right search terms.