happy easter all; lets say a USB2.0 hub is connected to a host , with many high-, full- and low-speed devices connected to it. as indicated in the USB system architecture , a full speed packet is heared only by full speed devices , same for low- high-speed devices. does this mean that the host sends low and full speed frames to high speed hub? if not how does the hub knows which packet is should go to which device? thanks Abukhater --------------------------------- Do you Yahoo!? Yahoo! Tax Center - File online by April 15th -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/usb/attachments/20040411/fdbd49fe/attachment.htm

-----Original Message----- From: usb-bounces@opencores.org [mailto:usb-bounces@opencores.org]On Behalf Of M. AbuKhater Sent: Sunday, April 11, 2004 2:09 PM To: usb@opencores.org Subject: [usb] 2.0 Hub happy easter all; lets say a USB2.0 hub is connected to a host , with many high-, full- and low-speed devices connected to it. > as indicated in the USB system architecture , a full speed packet > is heared only by full speed devices , same for low- high-speed devices. > does this mean that the host sends low and full speed frames to high speed hub? No, a high speed host communicates with a high speed device at high speed. The hub is a high speed device. > if not how does the hub knows which packet is should go to which device? Uh. The device address? Marc Reinig System Solutions -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/usb/attachments/20040411/f6258d41/attachment.htm

Actually I dashed that off too quick. High speed traffic is broadcast to all downstream high speed devices. If there is a low or full speed device down stream of a high speed hub, it will be attached as a low or full speed device either directly to a high speed port, or through a full speed hub, which will be connected as a full speed device. A high speed hub makes the speed conversion from high to full/low speed for the full/low speed device. It effectively acts like a host controller in this case. See 11.14 in the USB spec. Marc Reinig System Solutions -----Original Message----- From: usb-bounces@opencores.org [mailto:usb-bounces@opencores.org]On Behalf Of Marc Reinig Sent: Sunday, April 11, 2004 7:46 PM To: Discussion list about free,open source USB IP core Subject: RE: [usb] 2.0 Hub -----Original Message----- From: usb-bounces@opencores.org [mailto:usb-bounces@opencores.org]On Behalf Of M. AbuKhater Sent: Sunday, April 11, 2004 2:09 PM To: usb@opencores.org Subject: [usb] 2.0 Hub happy easter all; lets say a USB2.0 hub is connected to a host , with many high-, full- and low-speed devices connected to it. > as indicated in the USB system architecture , a full speed packet > is heared only by full speed devices , same for low- high-speed devices. > does this mean that the host sends low and full speed frames to high speed hub? No, a high speed host communicates with a high speed device at high speed. The hub is a high speed device. > if not how does the hub knows which packet is should go to which device? Uh. The device address? Marc Reinig System Solutions -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/usb/attachments/20040411/234fe525/attachment.htm

hi "A high speed hub makes the speed conversion from high to full/low speed for the full/low speed device. " Well, since the hub broadcasts, I don't think it can do speed conversion for all packets (USB2.0 is 40 times faster than 1.1), so how does it know that a certain packet is directed to this Full-speed device? Does the hub keeps the address and speed of each device connected to it as a database inside it? if so why does it broadcast ? Abukhater Marc Reinig mreinig@pacbell.net> wrote: Actually I dashed that off too quick. High speed traffic is broadcast to all downstream high speed devices. If there is a low or full speed device down stream of a high speed hub, it will be attached as a low or full speed device either directly to a high speed port, or through a full speed hub, which will be connected as a full speed device. A high speed hub makes the speed conversion from high to full/low speed for the full/low speed device. It effectively acts like a host controller in this case. See 11.14 in the USB spec. Marc Reinig System Solutions -----Original Message----- From: usb-bounces@opencores.org [mailto:usb-bounces@opencores.org]On Behalf Of Marc Reinig Sent: Sunday, April 11, 2004 7:46 PM To: Discussion list about free,open source USB IP core Subject: RE: [usb] 2.0 Hub -----Original Message----- From: usb-bounces@opencores.org [mailto:usb-bounces@opencores.org]On Behalf Of M. AbuKhater Sent: Sunday, April 11, 2004 2:09 PM To: usb@opencores.org Subject: [usb] 2.0 Hub happy easter all; lets say a USB2.0 hub is connected to a host , with many high-, full- and low-speed devices connected to it.

No, a high speed host communicates with a high speed device at high speed. The hub is a high speed device.

Uh. The device address? Marc Reinig System Solutions _______________________________________________ http://www.opencores.org/mailman/listinfo/usb --------------------------------- Do you Yahoo!? Yahoo! Tax Center - File online by April 15th -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/usb/attachments/20040412/2303297c/attachment.htm

Read chapters 8 and 11 of the spec about split transactions and the hub state machine. Basically, it is broadcast to all high speed devices, identifying packets headed for a full/low speed device. It is interpreted by any high speed hub which has a high speed link to the host. The hub then converts it to full/low speed packets and broadcasts that to any full/low speed devices attached, including full speed hubs, and on down the line, going to all attached full/low speed devices, until the packet eventually finds the full/low speed device with that address. All other full/low speed devices ignore the packet. Marc Reinig System Solutions -----Original Message----- From: usb-bounces@opencores.org [mailto:usb-bounces@opencores.org]On Behalf Of M. AbuKhater Sent: Monday, April 12, 2004 7:15 AM To: Discussion list about free, open source USB IP core Subject: RE: [usb] 2.0 Hub hi "A high speed hub makes the speed conversion from high to full/low speed for the full/low speed device. " Well, since the hub broadcasts, I don't think it can do speed conversion for all packets (USB2.0 is 40 times faster than 1.1), so how does it know that a certain packet is directed to this Full-speed device? Does the hub keeps the address and speed of each device connected to it as a database inside it? if so why does it broadcast ? Abukhater Marc Reinig mreinig@pacbell.net> wrote: Actually I dashed that off too quick. High speed traffic is broadcast to all downstream high speed devices. If there is a low or full speed device down stream of a high speed hub, it will be attached as a low or full speed device either directly to a high speed port, or through a full speed hub, which will be connected as a full speed device. A high speed hub makes the speed conversion from high to full/low speed for the full/low speed device. It effectively acts like a host controller in this case. See 11.14 in the USB spec. Marc Reinig System Solutions -----Original Message----- From: usb-bounces@opencores.org [mailto:usb-bounces@opencores.org]On Behalf Of Marc Reinig Sent: Sunday, April 11, 2004 7:46 PM To: Discussion list about free,open source USB IP core Subject: RE: [usb] 2.0 Hub -----Original Message----- From: usb-bounces@opencores.org [mailto:usb-bounces@opencores.org]On Behalf Of M. AbuKhater Sent: Sunday, April 11, 2004 2:09 PM To: usb@opencores.org Subject: [usb] 2.0 Hub happy easter all; lets say a USB2.0 hub is connected to a host , with many high-, full- and low-speed devices connected to it. > as indicated in the USB system architecture , a full speed packet > is heared only by full speed devices , same for low- high-speed devices. > does this mean that the host sends low and full speed frames to high speed hub? No, a high speed host communicates with a high speed device at high speed. The hub is a high speed device. > if not how does the hub knows which packet is should go to which device? Uh. The device address? Marc Reinig System Solutions _______________________________________________ http://www.opencores.org/mailman/listinfo/usb ---------------------------------------------------------------------------- -- Do you Yahoo!? Yahoo! Tax Center - File online by April 15th -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/usb/attachments/20040412/59adb13f/attachment.htm

Hi Abukhater, A high speed host communicates with a high speed device only in high speed. It would be of much use to you if you could study split transfers.It is via the split transfers that the high speed host communicates with a full/low speed device under the hub.The hub is responsible to properly decode the split transfers and redirect the transfers to the appropriate port. The hub at this point acts as a full/low speed host to the full/low speed device connected to it. Regards Ravi Rajarman ----- Original Message ----- From: M. AbuKhater To: usb@opencores.org Sent: Sunday, April 11, 2004 2:08 PM Subject: [usb] 2.0 Hub happy easter all; lets say a USB2.0 hub is connected to a host , with many high-, full- and low-speed devices connected to it. as indicated in the USB system architecture , a full speed packet is heared only by full speed devices , same for low- high-speed devices. does this mean that the host sends low and full speed frames to high speed hub? if not how does the hub knows which packet is should go to which device? thanks Abukhater ------------------------------------------------------------------------------ Do you Yahoo!? Yahoo! Tax Center - File online by April 15th ------------------------------------------------------------------------------ _______________________________________________ http://www.opencores.org/mailman/listinfo/usb -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/usb/attachments/20040412/d12602d8/attachment-0001.htm

hello ravi so I suppose that packets directed to a full-/low-speed device are broadcasted to all full-/low-speed devices connected to it, is that right? Abukhater Ravi Rajaraman ravi_prr2000@hotmail.com> wrote: Hi Abukhater, A high speed host communicates with a high speed device only in high speed. It would be of much use to you if you could study split transfers.It is via the split transfers that the high speed host communicates with a full/low speed device under the hub.The hub is responsible to properly decode the split transfers and redirect the transfers to the appropriate port. The hub at this point acts as a full/low speed host to the full/low speed device connected to it. Regards Ravi Rajarman ----- Original Message ----- From: M. AbuKhater To: usb@opencores.org Sent: Sunday, April 11, 2004 2:08 PM Subject: [usb] 2.0 Hub happy easter all; lets say a USB2.0 hub is connected to a host , with many high-, full- and low-speed devices connected to it. as indicated in the USB system architecture , a full speed packet is heared only by full speed devices , same for low- high-speed devices. does this mean that the host sends low and full speed frames to high speed hub? if not how does the hub knows which packet is should go to which device? thanks Abukhater --------------------------------- Do you Yahoo!? Yahoo! Tax Center - File online by April 15th --------------------------------- _______________________________________________ http://www.opencores.org/mailman/listinfo/usb_______________________________________________ http://www.opencores.org/mailman/listinfo/usb --------------------------------- Do you Yahoo!? Yahoo! Small Business $15K Web Design Giveaway - Enter today -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/usb/attachments/20040412/499487fa/attachment.htm

Hi Abu, Assume the following scenario.Host and hub(high speed). Host ---> Hub -------> Dev1 (full) | |-------------> Dev2 (low) | --------------> Dev3 (full) | |--------------> Dev4(low). In this case if a full speed transfer comes from the host,the hub decodes the split and sends that transfer to all the enabled downstream full speed ports ie dev1 and dev3. similar is the case for low speed. One point here is, all enabled downstream ports,keep that in mind. Regards, Ravi ----- Original Message ----- From: M. AbuKhater To: Discussion list about free, open source USB IP core Sent: Monday, April 12, 2004 11:14 PM Subject: Re: [usb] 2.0 Hub hello ravi so I suppose that packets directed to a full-/low-speed device are broadcasted to all full-/low-speed devices connected to it, is that right? Abukhater Ravi Rajaraman ravi_prr2000@hotmail.com> wrote: Hi Abukhater, A high speed host communicates with a high speed device only in high speed. It would be of much use to you if you could study split transfers.It is via the split transfers that the high speed host communicates with a full/low speed device under the hub.The hub is responsible to properly decode the split transfers and redirect the transfers to the appropriate port. The hub at this point acts as a full/low speed host to the full/low speed device connected to it. Regards Ravi Rajarman ----- Original Message ----- From: M. AbuKhater To: usb@opencores.org Sent: Sunday, April 11, 2004 2:08 PM Subject: [usb] 2.0 Hub happy easter all; lets say a USB2.0 hub is connected to a host , with many high-, full- and low-speed devices connected to it. as indicated in the USB system architecture , a full speed packet is heared only by full speed devices , same for low- high-speed devices. does this mean that the host sends low and full speed frames to high speed hub? if not how does the hub knows which packet is should go to which device? thanks Abukhater -------------------------------------------------------------------------- Do you Yahoo!? Yahoo! Tax Center - File online by April 15th -------------------------------------------------------------------------- _______________________________________________ http://www.opencores.org/mailman/listinfo/usb _______________________________________________ http://www.opencores.org/mailman/listinfo/usb ------------------------------------------------------------------------------ Do you Yahoo!? Yahoo! Small Business $15K Web Design Giveaway - Enter today ------------------------------------------------------------------------------ _______________________________________________ http://www.opencores.org/mailman/listinfo/usb -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/usb/attachments/20040413/e14e7440/attachment.htm

hi ravi that was really helpfull, thankx for the fast reply. two more things, 1. is this applicable for full-speed hub and several low-/full-speed devices? 2. for low speed devices, baud rate is the same as bit rate (i.e. 1.5M), is that right? regards Abukhater Ravi Rajaraman ravi_prr2000@hotmail.com> wrote: Hi Abu, Assume the following scenario.Host and hub(high speed). Host ---> Hub -------> Dev1 (full) | |-------------> Dev2 (low) | --------------> Dev3 (full) | |--------------> Dev4(low). In this case if a full speed transfer comes from the host,the hub decodes the split and sends that transfer to all the enabled downstream full speed ports ie dev1 and dev3. similar is the case for low speed. One point here is, all enabled downstream ports,keep that in mind. Regards, Ravi ----- Original Message ----- From: M. AbuKhater To: Discussion list about free, open source USB IP core Sent: Monday, April 12, 2004 11:14 PM Subject: Re: [usb] 2.0 Hub hello ravi so I suppose that packets directed to a full-/low-speed device are broadcasted to all full-/low-speed devices connected to it, is that right? Abukhater Ravi Rajaraman ravi_prr2000@hotmail.com> wrote: Hi Abukhater, A high speed host communicates with a high speed device only in high speed. It would be of much use to you if you could study split transfers.It is via the split transfers that the high speed host communicates with a full/low speed device under the hub.The hub is responsible to properly decode the split transfers and redirect the transfers to the appropriate port. The hub at this point acts as a full/low speed host to the full/low speed device connected to it. Regards Ravi Rajarman ----- Original Message ----- From: M. AbuKhater To: usb@opencores.org Sent: Sunday, April 11, 2004 2:08 PM Subject: [usb] 2.0 Hub happy easter all; lets say a USB2.0 hub is connected to a host , with many high-, full- and low-speed devices connected to it. as indicated in the USB system architecture , a full speed packet is heared only by full speed devices , same for low- high-speed devices. does this mean that the host sends low and full speed frames to high speed hub? if not how does the hub knows which packet is should go to which device? thanks Abukhater --------------------------------- Do you Yahoo!? Yahoo! Tax Center - File online by April 15th --------------------------------- _______________________________________________ http://www.opencores.org/mailman/listinfo/usb_______________________________________________ http://www.opencores.org/mailman/listinfo/usb --------------------------------- Do you Yahoo!? Yahoo! Small Business $15K Web Design Giveaway - Enter today --------------------------------- _______________________________________________ http://www.opencores.org/mailman/listinfo/usb_______________________________________________ http://www.opencores.org/mailman/listinfo/usb --------------------------------- Do you Yahoo!? Yahoo! Tax Center - File online by April 15th -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/usb/attachments/20040414/28c87cfd/attachment.htm