Hi, I'm planning to write an hc driver for the recent ISP1761 EHCI chip. I'm new to USB, and I have some questions. I hope gradually I'll ask smarter questions but I'm stuck with some basic bits of the USB2.0 spec for now.
I have trouble undertanding one-to-one or one-to-many relationships. 1) Is the following correct? Transaction 1<->M Packets Transfer 1<->M Transactions Endpoint 1<->M iTD 2) EHCI says an iTD can serve up to 24 transactions. This maps to 8 buffer pointers in an ITD and up to 3 transactions per buffer pointer depending on the Mult bit. Am I correct? 3) Also, the link relationships between TDs is the most confusing for me. There are iTDs listed in the periodic frame list with period 1, and also each iTDs in the frame list point at other iTDs via the next pointers. Now, does linking of iTDs via next pointers imply any relationship between them or are they independent? In other words, are a bunch of iTDs linked by next ptrs associated with an endpoint, or is it just a way of ordering them? 4) Also in a periodic frame list F with iTD0,iTD1,iTD2 ... as each entry, could it be true that (iTD0->next == iTD1)? If this list isn't the right place to ask these, apologies and I wont bother you any further. Many thanks, Bahadir ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_ide95&alloc_id396&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
