SAM7X256_14 Datasheet, PDF (432/662 Pages) ATMEL Corporation – ARM-based Flash MCU

34.5 Functional Description
34.5.1 USB V2.0 Full-speed Introduction
The USB V2.0 full-speed 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.
Figure 34-3. Example of USB V2.0 Full-speed Communication Control
USB Host V2.0
Software Client 1 Software Client 2
Data Flow: Control Transfer
Data Flow: Isochronous In Transfer
Data Flow: Isochronous Out Transfer
EP0
USB Device 2.0
EP1 _{Block 1}
EP2
Data Flow: Control Transfer
Data Flow: Bulk In Transfer
Data Flow: Bulk Out Transfer
EP0
USB Device 2.0
EP4 _{Block 2}
EP5
USB Device endpoint configuration requires that
in the first instance Control Transfer must be EP0.
The Control Transfer endpoint EP0 is always used when a USB device is first configured (USB v. 2.0 specifications).
34.5.1.1 USB V2.0 Full-speed Transfer Types
A communication flow is carried over one of four transfer types defined by the USB device.
Table 34-2. USB Communication Flow
Transfer
Direction
Bandwidth
Control
Bidirectional Not guaranteed
Isochronous
Unidirectional
Guaranteed
Interrupt
Unidirectional Not guaranteed
Bulk
Unidirectional Not guaranteed
Supported Endpoint Size
8, 16, 32, 64
256
≤ 64
8, 16, 32, 64
Error Detection
Yes
Yes
Yes
Yes
Retrying
Automatic
No
Yes
Yes
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
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