[PATCH] bsp/tms570: fix get time resolution after infrastructure change to timecounter.

Pavel Pisa pisa at cmp.felk.cvut.cz
Wed Jul 15 14:41:20 UTC 2015


Hello Martin and others,

On Wednesday 15 of July 2015 15:37:28 Martin Galvan wrote:
> Hello Premysl! Thanks for this patch.
>
> Could you tell us why is this patch needed, and where does the new
> formula come from? From what I saw, HALCoGen generates a macro called
> RTI_FREQ which has the value from the previous version of the formula
> (i.e. if BSP_PLL_OUT_CLOCK == 180 MHz, RTI_FREQ == 90).
>
> I also looked at the TMS570 Technical Reference Manual entry on CPUC0,
> but it doesn't mention that formula.
>
> It would also be nice if you mentioned which setup did you test this
> on (i.e. loading RTEMS from RAM or flash).

the code has been tested for internal RAM now.
We have more cleanups in the mind but headers are critical
for now. Premek is working on that, time for feedback
form previous e-mail passed without input so he plans
to send prepared changes as patch intended for inclusion/final
review today.

As for time resolution, we have made initial assumption
that 1usec is reasonable and has advantage, that it can be
maintained constant even if there are different PLL setups
between boards. Other option is to set resolution exactly
to PLL clock but at least I do not see big added value in that.

Best wishes,

            Pavel


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