Re: [Xylo-SDR] Saxo

[Philip Covington <p.covington@gmail.com>]

Let me add that it is not a problem with how Phil H has set it up.  It
is a problem with how the design of the Xylo itself is set up to use
the FX2.

Phil C

On 1/23/06, Philip Covington <p.covington@gmail.com> wrote:
> Hi Helmut,
>
> Comments below:
>
> On 1/23/06, vk4str <vk4str@netspace.net.au> wrote:
>
> > Bulk transport is unuseable for real audio. Bulk guarantees 100% correct
> > data content transfer but does not guarantee delivery on time!
>
> I am not so sure that it is unusable for audio with USB 2.0.  I would
> agree in the USB 1.1 case.
>
> > Whereas isochronous transfer does not guarantee 100% correct data
> > content but delivery will always be on time. Meaning that you could get
> > an incorrect bit delivered now and then but always on time. That is a
> > must for audio.
>
> I think iso mode was a kludge added to make USB 1 work with streaming
> audio type applications.  Most of the USB 2.0 devices that I have seen
> do not use iso mode since block mode is faster.
>
> > Phil, I suggest you abandon bulk transfer for audio because you will be
> > wasting your time. The other thing is that you will not achieve low
> > latency transport when you are not using the OS kernel drivers which
> > have been worked over pretty well by M$. usbaudio.sys has only one small
> > bug left the experts claim.
>
> I don't think that block transfer is a problem.  The USRP can get 32
> MBPS throughput with block transfer/USB 2.0.  I think the problem that
> Phil H is having relates to how the Xylo is set up as far as
> endpoints, the FIFO size/mode used, and the firmware.
>
> 73 de Phil C
>