Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet
Product codes
ATSAM4S-WPIR-RD
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
1006
40.6
Functional Description
40.6.1 USB 2.0 Full-speed Introduction
The USB 2.0 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 40-3.
Example of USB 2.0 Full-speed Communication Control
The Control Transfer endpoint EP0 is always used when a USB device is first configured (USB 2.0 specifications).
40.6.1.1 USB 2.0 Full-speed Transfer Types
A communication flow is carried over one of four transfer types defined by the USB device.
40.6.1.2 USB Bus Transactions
Each transfer results in one or more transactions over the USB bus. There are three kinds of transactions flowing
across the bus in packets:
Setup Transaction
Data IN Transaction
Data OUT Transaction
EP0
USB Host V2.0
Software Client 1
Software Client 2
Data Flow: Bulk Out Transfer
Data Flow: Bulk In Transfer
Data Flow: Control Transfer
Data Flow: Control Transfer
EP1
EP2
USB Device 2.0
Block 1
Block 1
USB Device 2.0
Block 2
Block 2
EP5
EP4
EP0
Data Flow: Isochronous In Transfer
Data Flow: Isochronous Out Transfer
USB Device endpoint configuration requires that
in the first instance Control Transfer must be EP0.
in the first instance Control Transfer must be EP0.
Table 40-4.
USB Communication Flow
Transfer
Direction
Bandwidth
Supported
Endpoint Size
Error Detection
Retrying
Control
Bidirectional
Not guaranteed
8, 16, 32, 64
Yes
Automatic
Isochronous
Unidirectional
Guaranteed
512
Yes
No
Interrupt
Unidirectional
Not guaranteed
≤ 64
Yes
Yes
Bulk
Unidirectional
Not guaranteed
8, 16, 32, 64
Yes
Yes