42.3 Block Diagram

Figure 42-1. UHPHS Block Diagram

Access to the USB host operational registers is achieved through the system bus client interface. The Open HCI host controller and Enhanced HCI host controller initialize host DMA transfers through the system bus host interface as follows:

  • Fetches endpoint descriptors and transfer descriptors
  • Accesses endpoint data from system memory
  • Accesses HC communication area
  • Writes status and retires transfer descriptor

Memory access errors (abort, misalignment) lead to an “Unrecoverable Error” indicated by the corresponding flag in the host controller operational registers.

The USB root hub is integrated in the USB host. Several USB downstream ports are available. The number of downstream ports can be determined by the software driver reading the root hub’s operational registers. Device connection is automatically detected by the USB host port logic.

USB physical transceivers are integrated in the product and driven by the root hub’s ports.