an address with uhci
On Mon, 28 Jun 2004, Tommy Faasen wrote:
>Here's a possibility: Maybe the stick takes a long time to reply to the >Setup packet -- just a little too long for the UHCI controller, which >reports an error. > But I already changed those delay's without any result?
I'm talking about a different delay. The ones you changed were the delays before the Set-Address message was sent to the device. What I'm referring to here is the time from when the Setup packet (the first packet in the Set-Address message) is sent to the device until the device sends back a reply packet. The maximum allowable length of that delay is given in the USB specification; it's a few microseconds.
> Maybe the OHCI controller is a little more lenient and >accepts the late reply. >
I get an immediate reponse from the ohci one.
Again, I'm talking about the difference between the UHCI controller thinking a 5-microsecond pause (or something on that order) is too long and the OHCI controller thinking it is short enough.
Alan Stern
Hi Alan,
I don't think you are right about this. The spec for low and high speed devices is very tight on bus turnaround times. A minimum of 2 bit times (166 ns) from the end of SE0 of the eop and a maximum of 6.5 bit times (541 ns). See table 7-14 in the usb 2.0 spec. This is for FS and LS only - I guess by definition since you are talking about UHCI and OHCI.
HTH Steve
_________________________________________________________________
FREE pop-up blocking with the new MSN Toolbar – get it now! http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/
-------------------------------------------------------
This SF.Net email sponsored by Black Hat Briefings & Training.
Attend Black Hat Briefings & Training, Las Vegas July 24-29 - digital self defense, top technical experts, no vendor pitches, unmatched networking opportunities. Visit www.blackhat.com
_______________________________________________
[EMAIL PROTECTED]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
