sleep time is doubled, xilinx_zynq_zedboard
Joel Sherrill
Joel.Sherrill at OARcorp.com
Thu May 1 13:03:48 UTC 2014
On May 1, 2014 7:35 AM, Thomas Doerfler <Thomas.Doerfler at embedded-brains.de> wrote:
>
> Giovanni,
>
> without knowing the BSP: You are talking about CPU clock, the macro is
> call Periphclk. Can it be that the peripheral bus is clocked with half
> of the CPU frequency?
In was thinking something similar Thomas (also in ignorance of this specific BSP). The main frequency may be correct but their may be two independent divider settings which can vary per implementation. This is "soft" hardware and could have a lot if potential tweak points. The BSP may or may not have the defaults to match your board instance and may or may not address all potential tweak points yet.
Are there dividers?
--joel
> wkr,
>
> Thomas.
>
> Am 01.05.2014 12:52, schrieb Giovanni Macciocu:
> > I've made some tests by changing the value of BSP_ARM_A9MPCORE_PERIPHCLK.
> > The value should be 666666667U as this is my cpu clock speed.
> >
> > However in the following cases
> >
> > #define BSP_ARM_A9MPCORE_PERIPHCLK (2 * 666666667U)
> >
> > --> a Sleep now takes 4 times as long
> >
> > #define BSP_ARM_A9MPCORE_PERIPHCLK 2 (666666667U / 2)
> >
> > --> The sleep is now correct
> >
> > In all cases the serial port keeps working at half of the normal buadrate.
> >
> > Regards,
> >
> > Giovanni
> >
> >
> >>>> "Giovanni Macciocu" <G.Macciocu at sron.nl> 5/1/2014 10:53 AM >>>
> > In my bspopt.h
> >
> > /* ARM Cortex-A9 MPCore PERIPHCLK clock frequency in Hz */
> > #define BSP_ARM_A9MPCORE_PERIPHCLK 666666667U
> >
> > This is the correct processor speed for my platform.
> >
> >>>> Chris Johns <chrisj at rtems.org> 5/1/2014 10:24 AM >>>
> > t you take a look at the BSPOPTS for the zync BSP. There are
> > some clocks you can set and one of these may help. I think
> > BSP_ARM_A9MPCORE_PERIPHCLK is the one.
> >
> > Chris
> >
> >
> >
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> >
> >
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>
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