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Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 396
UG585 (v1.11) September 27, 2016
Chapter 15: USB Host, Device, and OTG Controller
Control and Status Registers
The control and status registers include constants, configuration and operational/status for EHCI
compatibility (Host mode) and non-EHCI functions (Device, OTG and enhanced Host mode). The
registers are summarized in section 15.3.4 Register Overview.
Clocks
The ULPI interface and Protocol engine are clocked by the 60 MHz input on the ULPI interface (PHY
clock output). The AHB interface is clocked by the CPU_1x clock. The clock domain crossing between
the CPU_1x clock and the 60 MHz ULPI PHY clock for the Protocol engine is at the dual-port RAM.
Resets
There are several different types of resets associated with the USB controller, these are further
discussed in section 15.15.2 Reset Types.
Controller Resets
°
PS Reset System (full controller reset),
°
usb.USBCMD [RST] bit (partial controller reset useful for OTG).
ULPI PHY reset (output from PS GPIO).
USB Bus Resets
°
Auto-Reset feature in OTG mode.
°
USB reset control transfer.
15.1.5 Configuration, Control and Status
Software manages the controller itself (configuration and control) and a consistent set of data
structures and memory buffers for USB transactions. There are two data structure models (host and
data) and three controller modes (host, device, and OTG). OTG uses either the host or device mode.
The controller registers are outlined in Table 15-1 USB Controller Register Overview.
15.1.6 Data Structures
The controller processes descriptors to facilitate FS/LS and HS USB operations. Device and host
modes use descriptors in very different ways. The models are illustrated in Figure 15-4.