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23. USB Host Operating Modes
23.1 Pipe description
For the USB Host controller, the term of Pipe is used instead of Endpoint for the USB Device
controller. A Host Pipe corresponds to a Device Endpoint, as described in the USB specification:
Figure 23-1. Pipes and Endpoints in a USB system
In the USB Host controller, a Pipe will be associated to a Device Endpoint, considering the
Device Configuration Descriptors.
23.2 Detach
The reset value of the DETACH bit is 1. Thus, the firmware has the responsibility of clearing this
bit before switching to the Host mode (HOST set).
23.3 Power-on and Reset
The next diagram explains the USB host controller main states on power-on:
Figure 23-2. USB host controller states after reset
<any
other
state>
Device
Clock stopped
disconnection
Macro off
Host
Idle
Device
connection
Device
disconnection
Host
Ready
SOFE=0
Host
SOFE=1
Suspend
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ATMEL [ ATMEL ]
