Datasheet
522
AT32UC3A
30.7.3 USB Host Operation
30.7.3.1 Description of Pipes
For the USB controller in host mode, the term āpipeā is used instead of āendpointā (used in
device mode). A host pipe corresponds to a device endpoint, as described by the Figure 30-22
from the USB specification.
Figure 30-22. USB Communication Flow
In host mode, the USB controller associates a pipe to a device endpoint, considering the device
configuration descriptors.
30.7.3.2 Power-On and Reset
Figure 30-23 describes the USB controller host mode main states.
Figure 30-23. Host Mode States
After a hardware reset, the USB controller host mode is in the Reset state.
When the USB macro is enabled (USBE = 1) in host mode (ID = 0), its host mode state goes to
the Idle state. In this state, the controller waits for device connection with minimal power con-
sumption. The USB pad should be in the Idle state. Once a device is connected, the macro
enters the Ready state, what does not require the USB clock to be activated.
Ready
Idle
Device
Disconnection
<any
other
state>
Device
Connection
Macro off
Clock stopped
Device
Disconnection
Suspend
SOFE = 1
SOFE = 0
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