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Universal Serial Bus, OTG Capable Controller
MCF52211 ColdFire® Integrated Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 15-37
Figure 15-33. Dual Role A Device Flow Diagram
Table 15-38. State Descriptions for Figure 15-33
State Action Response
A_IDLE If ID Interrupt.
The cable has been un-plugged or a Type B cable has been
attached. The device now acts as a Type B device.
Go to B_IDLE
If the A application wants to use the bus or if the B device is
doing an SRP as indicated by an A_SESS_VLD Interrupt or
Attach or Port Status Change Interrupt check data line for 5
–10 msec pulsing.
Go to A_WAIT_VRISE
Turn on DRV_VBUS
A_WAIT_VRISE If ID Interrupt or if A_VBUS_VLD is false after 100 msec
The cable has been changed or the A device cannot support
the current required from the B device.
Go to A_WAIT_VFALL
Turn off DRV_VBUS
If A_VBUS_VLD interrupt Go to A_WAIT_BCON
A_WAIT_BCON After 200 msec without Attach or ID Interrupt. (This could wait
forever if desired.)
Go to A_WAIT_FALL
Turn off DRV_VBUS
A_VBUS_VLD Interrupt and B device attaches Go to A_HOST
Turn on Host Mode
A_HOST Enumerate Device determine OTG Support.
If A_VBUS_VLD/ Interrupt or A device is done and doesn’t
think he wants to do something soon or the B device
disconnects
Go to A_WAIT_VFALL
Turn off Host Mode
Turn off DRV_VBUS
If the A device is finished with session or if the A device wants
to allow the B device to take bus.
Go to A_SUSPEND
ID Interrupt or the B device disconnects Go to A_WAIT_BCON
A_IDLE
A_WAIT_VFALL A_WAIT_VRISE
A_PERIPHERAL
A_SUSPEND
B_IDLE
A_WAIT_BCON
A_HOST