Table 42-139. State descriptions for the dual role A device flow (continued)
State
Action
Response
A_SUSPEND
If ID Interrupt, or if 150 ms B disconnect timeout (This timeout value
could be longer) or if A_VBUS_VLD\ Interrupt
Go to A_WAIT_VFALL
Turn off DRV_VBUS
If HNP enabled, and B disconnects in 150 ms then B device is
becoming the host.
Go to A_PERIPHERAL
Turn off Host mode
If A wants to start another session
Go to A_HOST
A_PERIPHERAL
If ID Interrupt or if A_VBUS_VLD interrupt
Go to A_WAIT_VFALL
Turn off DRV_VBUS.
If 3 –200 ms of Bus Idle
Go to A_WAIT_BCON
Turn on Host mode
A_WAIT_VFALL
If ID Interrupt or (A_SESS_VLD/ & b_conn/)
Go to A_IDLE
42.7.2 OTG dual role B device operation
A device is considered a B device if it is connected to the bus with a USB Type B cable
or a USB Type Mini B cable.
A dual role B device operates as the following flow diagram and state description table
illustrates.
B_IDLE
B_HOST
B_SRP_INIT
B_WAIT_ACON
A_IDLE
B_PERIPHERAL
Figure 42-102. Dual role B device flow diagram
Chapter 42 Universal Serial Bus Full Speed OTG Controller (USBFSOTG)
K22F Sub-Family Reference Manual , Rev. 3, 7/2014
Freescale Semiconductor, Inc.
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