BeagleBoard XM C2, Reference Manual

Page: 109 / 163

REF: BB_SRM_xM
BeagleBoard-xM System
Reference Manual
Revision C2
Page 109 of 163
UART2_RX UART receive I 8
UART2_TX UART transmit O 6
GPT PWM
GPT9_PWMEVT PWM or event for GP timer 9 O 4
GPT11_PWMEVT PWM or event for GP timer 11 O 10
GPT10_PWMEVT PWM or event for GP timer 10 O 8
7.24.3 Power
The expansion connector provides two power rails. The first is the
VIO_1.8V rail which
is supplied by the TPS65950 . This rail is limited in the current it can supply from the
TPS65950 and what remains from the current consumed by the BeagleBoard and is
intended to be used to provide a rail for voltage level conversion only. It is not intended
to power a lot of circuitry on the expansion board. All signals from the BeagleBoard are
at 1.8V.
The other rail is the
DC_5V . The same restriction exits on this rail as mentioned in the
USB section. The amount of available power to an expansion board depends on the
available power from the DC supply or the USB supply from the PC.
7.24.4 Reset
The
nRESET signal is the main board reset signal. When the board powers up, this
signal will act as an input to reset circuitry on the expansion board. After power up, a
system reset can be generated by the expansion board by taking this signal low. This
signal is a 1.8V level signal.
7.24.5 Power Control
There is an additional open-drain signal on the connector called
REGEN . The purpose of
this signal is to provide a means to control power circuitry on the expansion card to turn
on and off the voltages. This insures that the power on the expansion board is turned on at
the appropriate time. Depending on what circuitry is provided on the expansion board, an
additional delay may be needed to be added before the circuitry is activated. Refer to the
processor and
TPS65950 documentation for more information.
7.25 LCD Expansion Header
If you choose not to use the LCD headers for access to the LCD signals or for the DVI-D
interface, they can also be used for other functions on the board based on the pin mux
setting of each pin.
Table 24 shows the options for P11 and Table 25 shows the options
for P135 . The MUX: column indicates which MUX mode must be set for each pin to
make the respective signals accessible on the pins of the processor.