Texas Instruments Stellaris LM3S9D90, Руководство пользователя

Страница: 13 / 32

Stellaris® LM3S9D90 Evaluation Kit User’s Manual
July 5, 2011 13
PWR/UART
The PWR/UART connector J2 is used to provide 5 V power from the ICDI board and also to
connect the LM3S9D90 UART0 signals. This is a 2x4 fine pitch (0.050") connector, see
(Figure 2-4) for signal definition. The UART0 signals are connected to GPIO jumpers JR1 and JR2
and can be disconnected from connector J2 if required, see “GPIO Jumpers” on page 12. The
ICDI board connects via an 8-wire ribbon cable to this connector.
Figure 2-4. PWR/UART Connector
Ethernet, USB, Power and Miscellaneous (Schematic page 21)
Page 2 of the schematics contains the Ethernet RJ45 connector, USB power switch and USB OTG
connector, 3.3 V regulator, and power switch selector.
Ethernet Port
The on-board RJ45 connector provides a 10/100 base T Ethernet port. The RJ45 connector
includes integrated LEDs and magnetics. The LEDs are connected to GPIO jumpers JR4 and JR5
and can be disconnected from the RJ45 connector if required, see GPIO Jumpers section.
USB Port
The on-board USB microAB connector provides a USB 2.0 full-speed port. To use as an On-The-
Go (OTG) port, the power selector switch SW3 lever must be set to EXT. This selects an external
5 V power source to provide power to the board and the USB power switch. If the SW3 lever is set
to USB, power to the board is received from USB, the on-board USB power switch output is
disconnected from USB, and the board can only be used as a USB device. When using the
USB-OTG port in Host mode, the current provided to a USB device should be limited to 100 mA or
less when powered from the ICDI board. If powered from the 5 V test pad, then this can be
increased to 500 mA.
Board Power
The board requires 5 V for operation, and switch SW3 is used to select the power source. If the
switch lever is moved towards the USB label on the board, power is received from the USB
connector. If the switch lever is moved towards the EXTernal board label, the board is powered
from the PWR/UART connector and the ICDI board provides power to this connector. DC regulator
U2 generates 3.3 V for powering the board circuits and includes power indicator LED D1.
User Devices
Pushbutton switch SW2 and LED D2 are available for the user and connected to PB4 and PD0
respectively. These GPIOs are connected to GPIO jumpers JR3 and JR4 and can be
disconnected from SW2 and D2 if required, see GPIO Jumpers section.
VCP_TX
VCP_RX
GND
GND
DBG1
1 2
7 8
DBG2
5V 5V
In
Out
Out
Out