On Tue, Jul 31, 2012 at 1:08 AM, Alan Stern wrote:
> On Mon, 30 Jul 2012, Alexey Filin wrote:
>
>> > Yes, something like it might work, I think. But you probably wouldn't
>> > want to use URBs for this; they have too much overhead. You'd need a
>> > more direct interface to the host controller d
On Mon, 30 Jul 2012, Alexey Filin wrote:
> > Yes, something like it might work, I think. But you probably wouldn't
> > want to use URBs for this; they have too much overhead. You'd need a
> > more direct interface to the host controller driver.
>
> really, too much, about 7 us on my pc (Core2 D
On Mon, 30 Jul 2012, Alexey Filin wrote:
> On Thu, Jul 26, 2012 at 7:47 PM, Alan Stern wrote:
> > You can do this only by hacking up a special driver of your own.
> > Since transfer completions would not be reported by IRQs in time, you
> > would have to poll for transfer completions at microseco
On Thu, Jul 26, 2012 at 7:47 PM, Alan Stern wrote:
> You can do this only by hacking up a special driver of your own.
> Since transfer completions would not be reported by IRQs in time, you
> would have to poll for transfer completions at microsecond intervals.
> This would present a rather large
Alexey Filin wrote:
> On Sat, Jul 28, 2012 at 8:50 PM, Clemens Ladisch wrote:
>> Alexey Filin wrote:
>>> On Fri, Jul 27, 2012 at 5:04 PM, Peter Stuge wrote:
If you require consumer interfaces and you want neither USB nor
Ethernet then I guess there is only FireWire left to choose from.
On Sat, Jul 28, 2012 at 8:50 PM, Clemens Ladisch wrote:
> Alexey Filin wrote:
>> On Fri, Jul 27, 2012 at 5:04 PM, Peter Stuge wrote:
>>> If you require consumer interfaces and you want neither USB nor
>>> Ethernet then I guess there is only FireWire left to choose from.
>>
>> "The FireWire host i
Alexey Filin wrote:
> On Fri, Jul 27, 2012 at 5:04 PM, Peter Stuge wrote:
>> If you require consumer interfaces and you want neither USB nor
>> Ethernet then I guess there is only FireWire left to choose from.
>
> "The FireWire host interface supports DMA and memory-mapped devices"
This is the in
On Fri, Jul 27, 2012 at 9:08 PM, Peter Stuge wrote:
>> 2. To provide link to external bus adapter with 1 us delay and use the
>> same USB link from first use case. Not possible with USB. :(
>
> You didn't expand on the details, as I asked for, so I can't really
> comment much more.
>
> The point I
Alexey Filin wrote:
> >> For 2-byte read/write we could use either two bulk IN/OUT
> >> endpoints (131 * 8kHz ~ 1 MHz) or one control endpoint (table 5-3, 42
> >> * 8 kHz = 336 kHz).
> >
> > If you can expand further on the details of your application then you
> > will be able to get possibly unpar
On Fri, Jul 27, 2012 at 7:10 PM, Alan Stern wrote:
> On Fri, 27 Jul 2012, Alexey Filin wrote:
>
>> So USB is not a "classic" bus and not universal, it is a network with
>> non-constant delay.
>>
>> Are there USB controllers with the "synchronous transfers" reported
>> not on microframe boundary, s
On Fri, Jul 27, 2012 at 5:04 PM, Peter Stuge wrote:
> Alexey Filin wrote:
>> So USB is not a "classic" bus and not universal, it is a network
>> with non-constant delay.
>
> Whatever "classic" bus means.. USB is a packet-based communications
> bus with well-defined timing characteristics.
>
> It i
On Friday 27 July 2012 17:12:51 Alan Stern wrote:
> On Fri, 27 Jul 2012, Hans Petter Selasky wrote:
> > On Friday 27 July 2012 10:52:11 Alexey Filin wrote:
> > > USB is a good choice for some bus adapters, it is used widely, cheap,
> > > simple. For 2-byte read/write we could use either two bulk IN
On Fri, 27 Jul 2012, Hans Petter Selasky wrote:
> On Friday 27 July 2012 10:52:11 Alexey Filin wrote:
> > USB is a good choice for some bus adapters, it is used widely, cheap,
> > simple. For 2-byte read/write we could use either two bulk IN/OUT
> > endpoints (131 * 8kHz ~ 1 MHz) or one control en
On Fri, 27 Jul 2012, Alexey Filin wrote:
> So USB is not a "classic" bus and not universal, it is a network with
> non-constant delay.
>
> Are there USB controllers with the "synchronous transfers" reported
> not on microframe boundary, so we can get response less 125 us?
> Is there any USB2.0 sp
On Friday 27 July 2012 10:52:11 Alexey Filin wrote:
> USB is a good choice for some bus adapters, it is used widely, cheap,
> simple. For 2-byte read/write we could use either two bulk IN/OUT
> endpoints (131 * 8kHz ~ 1 MHz) or one control endpoint (table 5-3, 42
> * 8 kHz = 336 kHz). Ethernet is o
Alexey Filin wrote:
> So USB is not a "classic" bus and not universal, it is a network
> with non-constant delay.
Whatever "classic" bus means.. USB is a packet-based communications
bus with well-defined timing characteristics.
It is obviously not a local bus, as you know from PC architecture the
On Thu, Jul 26, 2012 at 7:59 PM, Hans Petter Selasky wrote:
> On Thursday 26 July 2012 17:47:11 Alan Stern wrote:
>> To get maximum throughput you should submit multiple URBs originally,
>> and then submit a new URB whenever an URB completes. I recommand using
>> a pipeline depth of 10-20 ms. Fo
On Thu, 26 Jul 2012, Alexey Filin wrote:
> transfer with 2kB per URB hits artificial limit in our read out module
> (19 MB/s for 128 kB URB). I think difference in performance for
> pipeline of concurrent URBs and one iterative URB with 128 kB buffer
> will be negligible, 128 kB URB takes at least
On Thu, Jul 26, 2012 at 7:47 PM, Alan Stern wrote:
> On Thu, 26 Jul 2012, Alexey Filin wrote:
>
>> Hello,
>>
>> I work in a scientific organization (www.ihep.su, experiments in high
>> energy physics). My colleagues developed a crate controller with
>> buffer memory and a usb interface (read out m
On Thursday 26 July 2012 17:47:11 Alan Stern wrote:
> To get maximum throughput you should submit multiple URBs originally,
> and then submit a new URB whenever an URB completes. I recommand using
> a pipeline depth of 10-20 ms. For bulk transfers at high speed, that
> comes out to between 500 KB
On Thursday 26 July 2012 17:47:11 Alan Stern wrote:
> > * Is there a USB controller with scheduling in current microframe?
>
> They all do it. But they won't generate completion IRQs any faster
> than 8 KHz.
Hi,
Maybe a bit off-topic: I've noticed that if you STALL a USB transfer, this
rule
On Thu, 26 Jul 2012, Alexey Filin wrote:
> Hello,
>
> I work in a scientific organization (www.ihep.su, experiments in high
> energy physics). My colleagues developed a crate controller with
> buffer memory and a usb interface (read out module, rom) to read out
> crate electronics with cypress ez
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