Texas Instruments OMAP5912 Reference Manual page 1585

SPRU761A
Proper initialization of the OMAP5912 device to support this mode of operation
requires proper setting of the top-level pin multiplexing for these pins:
-
MCBSP3.CLKX/USB1.TXEN
-
MCSI1.DOUT/USB1.TXD
-
RTC_WAKE_INT/USB1.SE0
-
CLK32K_OUT/USB1.SPEED
-
MPU_BOOT/USB1.SUSP
See Table 74.
HMC_MODE must be set to a value that routes the USB device controller to
USB pin group 1 (see Table 73). OTG_SYSCON_1.USB1_TRX_MODE must
be set to 1 to allow proper bidirectional operation of the 4-wire USB transceiver.
OTG_SYSCON_2.USBx_SYNCHRO must be set to allow proper bidirectional
signaling on
RTC_WAKE_INT/USB1.SE0.
A USB OTG transceiver can be used to provide USB device-only functionality
instead of a USB transceiver, with appropriate I
In this case, OTG_SYSCON_2.OTG_PADEN must be 0 and software passes
VBUS validity information from the USB OTG transceiver to the device
controller by reading VBUS status via the I
to the device controller via OTG_CTRL.BSESSVLD. In this case, the OTG
transceiver ID pin is left unconnected and OTG functionality is not available.
Because the OTG transceiver provides integrated D+ pullup capability,
suspend mode control, and D+/D- pulldown controls, those hardware features
shown can be removed when an OTG transceiver is used. System software
needs to control those features via the OTG transceiver I
When OTG_SYSCON_2.OTG_PADEN is 1, the status of GPIO0/USB.VBUS
is automatically provided to the USB device controller via hardware
mechanisms (when HMC_MODE provides USB device functionality to a USB
pin group). When OTG_SYSCON_2.OTG_PADEN is 0, the USB device
controller only sees the VBUS status from the software-controlled register
OTG_CTRL.BSESSVLD bit. In this case, software must monitor the
VBUS_DETECT signal (using GPIO0 if wired as shown), and update
OTG_CTRL.BSESSVLD whenever the VBUS_DETECT signal changes.
pins MCSI1.DOUT/USB1.TXD
2
C and interrupt connectivity.
2
C link and updating the value sent
Universal Serial Bus (USB)
USB OTG Controller
and
2
C register set.
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