35.7.1 OTG dual role A device operation
A device is considered the A device because of the type of cable attached. If the USB
Type A connector or the USB Type Mini A connector is plugged into the device, it is
considered the A device.
A dual role A device operates as the following flow diagram and state description table
illustrates.
A_IDLE
A_WAIT_VFALL A_WAIT_VRISE
A_PERIPHERAL
A_SUSPEND
B_IDLE
A_WAIT_BCON
A_HOST
Figure 35-93. Dual role A device flow diagram
Table 35-96. State descriptions for the dual role A device flow
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
Table continues on the next page...
On-The-Go operation
KL25 Sub-Family Reference Manual, Rev. 3, September 2012
648 Freescale Semiconductor, Inc.
To Next Page
Loading...
