Version 1.0 17-1
Chapter 17
Universal Serial Bus Device
The USB Device is compatible with the USB 1.1 and 2.0 Full Speed specification and com-
patible with both OpenHCI and Intel UHCI standards. This USB Device supports USB-
standard Full-Speed (12 Mbit/s) operation, and SUSPEND and RESUME signalling. Four
Endpoints (EP[3:0]) are supported which allow Bulk/Interrupt or Isochronous transfer.
Each of the Endpoints has a separate in and out FIFO (except EP0 which shares a FIFO
between IN and OUT). The FIFOs allow DMA access.
Figure 17-1 shows the USB Device block diagram. The individual blocks in the diagram
are described in the subsequent sections.
17.1 Theory of Operation
The LH79524 and LH79525 implement a USB Device only. All USB communications are
managed by one or more external USB Hosts. The USB Device is identical in both parts,
so all descriptions apply to the LH79524 and LH79525.
Figure 17-1. USB Block Diagram
LH79525-5
ENDPOINT CONTROL
DMA
INTERFACE
AHB
MASTER
AHB
SLAVE
INTERRUPTS
DMA
INTERFACE
RAM
CONTROLLER
SIEUSB
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