Altera cyclone V Technical Reference page 2099

cv_5v4
2016.10.28
Host Protocol
In host mode, the MAC performs the following functions:
• Detects connect, disconnect, and remote wakeup events on the USB link
• Initiates reset
• Initiates speed enumeration processes
• Generates Start of Frame (SOF) packets.
Device Protocol
In device mode, the MAC performs the following functions:
• Handles USB reset sequence
• Handles speed enumeration
• Detects USB suspend and resume activity on the USB link
• Initiates remote wakeup
• Decodes SOF packets
OTG Protocol
The MAC handles HNP and SRP for OTG operation. HNP provides a mechanism for swapping host and
device roles. SRP provides mechanisms for the host to turn off V
request a new USB session.
Wakeup and Power Control
To reduce power, the USB OTG controller supports a power-down mode. In power-down mode, the
controller and the PHY can shut down their clocks. The controller supports wakeup on the detection of
the following events:
• Resume
• Remote wakeup
• Session request protocol
• New session start
PHY Interface Unit
The USB OTG controller supports synchronous SDR data transmission to a ULPI PHY. The SDR mode
implements an eight-bit data bus.
DMA
The DMA has two modes of operation. You program your software to select between scatter-gather DMA
mode or buffer DMA mode depending on the controllers function.
If the controller is functioning as a generic root hub, you should program your software to select the buffer
DMA mode that supports split transfers.
If generic root hub functionlaity is not required, or if the controller is configured in Device mode, you can
program your software to select scatter-gather DMA mode.
If you wish to dynamically switch the mode of operation based on the queried device status or capability,
your software driver must cleanly switch between the two modes of operation. For example, you may want
the controller to default to scatter-gather DMA mode and only change mode when it detects a generic
HUB with fast-speed and low-speed capability. Some basic requirements for switching include:
USB 2.0 OTG Controller
Send Feedback
Host Protocol
to save power, and for a device to
BUS
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