Texas Instruments OMAP5912 Reference Manual page 1505

Table 67. OTG Control Register (OTG_CTRL) (Continued)
Bit Name
10 Reserved
9 B_HNPEN
8 B_BUSREQ
7 OTG_BUSDROP
6 Reserved
SPRU761A
Description
Reserved
B-device HNP enable (when acting as default-B device). When OTG is
enabled (OTG_EN = 1) and OMAP5912 is acting as a default-B device
(OTG_CTRL.ID = 1), system software must set this bit when the USB
device receives a set feature operation with feature selector
B_HNP_ENABLE. System software clears this bit whenever it sends USB
reset to the
default−B device. This bit has no meaning when OTG_EN = 0 or when
OTG_CTRL.ID = 0.
0: B-device is not HNP enabled. The OTG controller does not issue HNP.
1: B-device is HNP enabled. The OTG controller can issue HNP when
B_BUSREQ is set.
This bit is cleared 0 by soft reset or hardware reset.
Bus request (when acting as default-B device). When OTG is enabled
(OTG_EN = 1) and OMAP5912 is acting as a default-B device
(OTG_CTRL.ID = 1), system software sets this bit when the application
wishes to take ownership of the OTG link and begin acting as a host. When
set, this allows the OTG controller to issue SRP if a session is not currently
valid, and to begin HNP at the next available opportunity if HNP is enabled
(OTG_CTRL.B_HNPEN = 1). This bit is ignored by the OTG controller
when OTG_CTRL.ID = 0.
0: System software does not currently wish to begin acting as host.
1: System software (acting as a default-B device) wishes to begin acting as
host. HNP and, if necessary, SRP are issued.
This bit is cleared 0 by soft reset or hardware reset.
The OTG controller clears this bit if there is not a valid session and the
SRP fails. The OTG controller clears this bit if there is a valid session but
the HNP fails. If SRP or HNP fails, system software repeats the request
several times. If the SRP or HNP request fails several times, system
software must inform the user of the failure.
OTG bus drop request. When OTG is enabled (OTG_EN = 1) and
OMAP5912 is acting as a default-A device (OTG_CTRL.ID = 0), system
software requests the end of a session by setting this bit. This bit has no
effect when OTG_CTRL.ID = 1.
0: System software does not require the end of the OTG session.
1: System software requires that the OTG session be ended.
This bit is cleared 0 by soft reset or hardware reset.
Reserved
USB OTG Controller
Universal Serial Bus (USB) 213