Datasheet

505
SAM9X35 [DATASHEET]
11055E–ATARM–10-Mar-2014
32.6 Functional Description
32.6.1 UTMI Transceivers Sharing
The High Speed USB Host Port A is shared with the High Speed USB Device port and connected to the second UTMI
transceiver. The selection between Host Port A and USB Device is controlled by the UDPHS enable bit (EN_UDPHS)
located in the UDPHS_CTRL control register.
Figure 32-3. USB Selection
32.6.2 USB V2.0 High Speed Device Port Introduction
The USB V2.0 High Speed Device Port provides communication services between host and attached USB devices. Each
device is offered with a collection of communication flows (pipes) associated with each endpoint. Software on the host
communicates with a USB Device through a set of communication flows.
32.6.3 USB V2.0 High Speed Transfer Types
A communication flow is carried over one of four transfer types defined by the USB device.
A device provides several logical communication pipes with the host. To each logical pipe is associated an endpoint.
Transfer through a pipe belongs to one of the four transfer types:
 Control Transfers: Used to configure a device at attach time and can be used for other device-specific purposes,
including control of other pipes on the device.
 Bulk Data Transfers: Generated or consumed in relatively large burst quantities and have wide dynamic latitude in
transmission constraints.
 Interrupt Data Transfers: Used for timely but reliable delivery of data, for example, characters or coordinates with
human-perceptible echo or feedback response characteristics.
 Isochronous Data Transfers: Occupy a prenegotiated amount of USB bandwidth with a prenegotiated delivery
latency. (Also called streaming real time transfers.)
As indicated below, transfers are sequential events carried out on the USB bus.
Endpoints must be configured according to the transfer type they handle.
Other
Transceivers
DMA
HS USB Host
HS EHCI
FS OHCI
Others Ports PA
1
0
EN_UDPHS
HS
USB
Device
HS
Transceiver
DMA
Table 32-2. USB Communication Flow
Transfer Direction Bandwidth Endpoint Size Error Detection Retrying
Control Bidirectional Not guaranteed 8, 16, 32, 64 Yes Automatic
Isochronous Unidirectional Guaranteed 8-1024 Yes No
Interrupt Unidirectional Not guaranteed 8-1024 Yes Yes
Bulk Unidirectional Not guaranteed 8-512 Yes Yes