SAM3S8C Atmel Corporation, SAM3S8C Datasheet - Page 968

• Manufacturer Part Number: SAM3S8C
• Manufacturer: Atmel Corporation

36.6.3
968
968
SAM3S8/SD8
SAM3S8/SD8
Controlling Device States
A USB device has several possible states. Refer to Chapter 9 of the Universal Serial Bus Speci-
fication, Rev 2.0.
Figure 36-15. USB Device State Diagram
Movement from one state to another depends on the USB bus state or on standard requests
sent through control transactions via the default endpoint (endpoint 0).
After a period of bus inactivity, the USB device enters Suspend Mode. Accepting Sus-
pend/Resume requests from the USB host is mandatory. Constraints in Suspend Mode are very
strict for bus-powered applications; devices may not consume more than 500 µA on the USB
bus.
While in Suspend Mode, the host may wake up a device by sending a resume signal (bus activ-
ity) or a USB device may send a wake up request to the host, e.g., waking up a PC by moving a
USB mouse.
The wake up feature is not mandatory for all devices and must be negotiated with the host.
Reset
Interruption
Power
Deconfigured
Deconfigured
Hub Reset
Device
or
Configured
Attached
Powered
Address
Default
Configured
Configured
Assigned
Address
Hub
Device
Reset
Bus Inactive
Bus Inactive
Bus Inactive
Bus Inactive
Bus Activity
Bus Activity
Bus Activity
Bus Activity
Suspended
Suspended
Suspended
Suspended
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12