AT85C51SND3Bx
USB Host Operating Modes
Pipe Description
For the USB Host controller, the term of Pipe is used instead of Endpoint for the USB
Device controller (see Figure 64). A Host Pipe corresponds to a Device Endpoint, as
described in the USB specification.
Figure 64. 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.
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).
Power-on and Reset
Figure 65 shows the USB host controller main states after power-on.
Figure 65. USB Host Controller Reset State Machine
<any
Device
Clock stopped
other
disconnection
Macro off
state>
Host
Idle
Device
connection
Device
disconnection
Host
Ready
SOFE=0
Host
SOFE=1
Suspend
USB host controller state after an hardware reset is ‘Reset’. When the USB controller is
enabled and the USB Host controller is selected, the USB controller is in ‘Idle’ state. In
this state, the USB Host controller waits for the Device connection, with a minimum
power consumption. The USB Pad should be in Idle mode. The macro does not need
to have the PLL activated to enter in ‘Host Ready’ state.
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ATMEL [ ATMEL ]
