User manual

Table Of Contents
Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 392
UG585 (v1.11) September 27, 2016
Chapter 15: USB Host, Device, and OTG Controller
15.1.2 Operating Modes
The USB controller can operate in the modes shown in Figure 15-1.
Host mode. In host mode, the software includes driver-layer programming to discover and
enumerate the bus, manage PHY operations, and setup the periodic and asynchronous schedules of
transfer descriptors.
°
EHCI software model except as described in section 15.11 EHCI Implementation.
Device mode. In device mode, the controller responds to host commands. Software can include
driver-layer programming to respond, as a single- or multi-function device, to the upstream
commands.
On-the-Go. The OTG software switches between Host and Device modes based on the Host
Negotiated Protocol (HNP) and the Session Request Protocol (SRP). Once the controller is in device
or host mode, it has all the functionality of the selected mode.
15.1.3 Hardware System Viewpoint
The USB controllers are integrated into the PS IOP to bridge between the PS interconnect and an
external ULPI PHY. The controller’s registers are memory mapped and the local DMA engine initiates
reads and writes to system memory. The ULPI signals flow through the MIO. There are sideband
signals (port indicators and power controls) that flow through the EMIO interface where they are
normally routed to PL SelectIO pins. The system-level viewpoint is shown in Figure 15-2.
X-Ref Target - Figure 15-1
Figure 15-1: USB Controller Operating Modes
UG585_c15_30_030712
Host Mode
Zynq PHY
Zynq PHY
Device or
Downstream Hub
HNP
SRP
HS: EHCI
FS/LS: TT in EHCI
Device Mode
Zynq
HS, FS
Host or
Upstream Hub
OTG
Zynq PHY
Another OTG
Device