[ECOS] Timing differences before / after starting scheduler

[Tim Jaacks]

> Polling status/data from the FIFO generates quite a bit of traffic
> on the chip's bus - I don't know how exactly the APB and AHB/APB
> bridge work. I mean the speed you are demanding is maybe
> too much for the worst case that can happen on the bus
> (arbitrations etc). Add to that that you probably need
> an interrupt to tell you there is first data, interrupt latency
> and driver reaction time - maybe this is too much for a real
> application.
>
> I think for this case the DMA is surely a better idea.
>
> See also http://permalink.gmane.org/gmane.comp.hardware.arm.lpc2100/49688 -
> someone had problems even using the DMA ...
>
> Why this runs more 3 times slower if there is nothing but
> this thread running with disabled interrupts, I have no idea...
>
>   
Thanks very much for the link, that was very interesting to read!
Seems as if using DMA is the only practical way to get the interface 
running at that high speed.

Anyway, I still find it confusing that the actions take more time when 
the scheduler is started. If anyone has an idea, why this might be the 
case, please reply on this thread. I will be very thankful.

Thanks very much and best wishes,

Tim

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