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From: "Kevyn-Alexandre Paré" <kapare-7qmld2CjetYf4mhTGKTGE9BPR1lH4CV8@public.gmane.org>
To: Jassi Brar <jassisinghbrar-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	gumstix-users-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: How to mesure current SPI transfer speed
Date: Mon, 10 Jan 2011 20:25:00 +0000	[thread overview]
Message-ID: <1294691100.5312.16.camel@andromeda> (raw)
In-Reply-To: <AANLkTimexzqAafU7dWj8QY1Oaac5wUoEj=pp6gqkcuqE-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>



On Sat, 2011-01-08 at 11:16 +0900, Jassi Brar wrote:
> On Sat, Jan 8, 2011 at 3:51 AM, Kevyn-Alexandre Paré
> <kapare@rogue-research.com> wrote:
> > Hi,
> >
> > What's the best way to calculate the current SPI transfer speed?
> >
> > Right now I use something like that and transfer one spi_message with 1
> > spi_transfer of 100000 bytes and I do the math... I know that this is
> > not accurate and was wondering if anyone have a better way?
> >
> >
> > struct timeval tv_before;
> > struct timeval tv_after;
> >
> > do_gettimeofday(&tv_before);
> >    status = spi_sync(spike_dev.spi_device, &spike_ctl.msg);
> > do_gettimeofday(&tv_after);
> >    long elapsedTime = (tv_after.tv_usec - tv_before.tv_usec);
> 
> Transfer speed is tightly linked to MOSI/MISO bit rates.
> But the overall throughput would depend on the protocol that
> you run over SPI.

Effectively, but how to monitor that I respect, for example, a
requirement of 5Mbps with a chip... I'm already sending data at

#define SPI_BUS_SPEED 5000000
spi_device->max_speed_hz = SPI_BUS_SPEED;

So does this settings ensure it to always be at 5Mhz?

I will try to test it by settings it to higher speed to see what happen
ex: 48000000 (48Mhz)

Regards,

--
Kevyn-Alexandre Pare





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  parent reply	other threads:[~2011-01-10 20:25 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-07 18:51 How to mesure current SPI transfer speed Kevyn-Alexandre Paré
2011-01-08  2:16 ` Jassi Brar
     [not found]   ` <AANLkTimexzqAafU7dWj8QY1Oaac5wUoEj=pp6gqkcuqE-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2011-01-10 20:25     ` Kevyn-Alexandre Paré [this message]
2011-01-12  2:29       ` Jassi Brar

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