NXP Semiconductors QorIQ LS1012A Reference Manual

This field in a siTD is used to complete an IN split-transaction using the previous H-Frame's siTD. This is only used when the scheduling of the complete-splits span anH-Frame boundary.There exists a one-to-one relationship between a high-speed isochronous split transaction(including all start- and complete-splits) and one full-speed isochronous transaction. AnsiTD contains (amongst other things) buffer state and split transaction schedulinginformation. An siTD's buffer state always maps to one full-speed isochronous datapayload. This means that for any full-speed transaction payload, a single siTD's databuffer must be used. This rule applies to both IN an OUTs. An siTD's schedulinginformation usually also maps to one high-speed isochronous split transaction. Theexception to this rule is the H-Frame boundary wrap cases mentioned above.The siTD data structure describes at most, one frame's worth of high-speed transactionsand that description is strictly bounded within a frame boundary. The figure belowillustrates some examples. On the top are examples of the full-speed transactionfootprints for the boundary scheduling cases described above. In the middle are time-frame references for both the B-Frames (HS/FS/LS Bus) and the H-Frames. On thebottom is illustrated the relationship between the scope of an siTD description and thetime references. Each H-Frame corresponds to a single location in the periodic frame list.The implication is that each siTD is reachable from a single periodic frame list location ata time.Chapter 32 Universal Serial Bus Interface 2.0QorIQ LS1012A Reference Manual, Rev. 1, 01/2018NXP Semiconductors 2043