Texas Instruments OMAP5912 Reference Manual page 1602

USB OTG Controller
UART 1 on USB Pin Group 2 Pins
Figure 89. External Connectivity When USB Pin Group 1 Configured for UART1
Signalling
MCSI1.DOUT/USB1.TXD(TX1)
MCSI1.DIN/USB1.RCV(CTS1)
MCSI1.CLK/USB1.VM(RX1)
OMAP5912
310 Universal Serial Bus (USB)
When configured for some HMC_MODE values, the USB signal multiplexing
mechanism routes UART1 signals to some OMAP5912 USB pin group 1 pins
(see Figure 89).
U1
Proper initialization of the OMAP5912 device to support this mode of operation
requires proper setting of the top-level pin multiplexing for these pins:
-
MCSI1.DOUT/USB1.TXD
-
MCSI1.BCLK/USB1.VM
-
MCSI1.DIN/USB1.RCV
See Table 74.
HMC_MODE must be set to a value that routes the UART1 to USB pin group
1 (see Table 73). OTG_SYSCON_1.USB1_TRX_MODE must be set to 3 to
allow proper operation of the 3-wire connection to the external transceiver.
U2
RS232
transceiver
U1
OMAP5912
U2
RS232 transceiver
J1 RS232 connector
J1
SPRU761A