Texas Instruments Stellaris LM3S2965, Руководство пользователя, Страница: 15 / 32

Stellaris® LM3S2965 Evaluation Board
January 6, 2010 15
Two solutions exist. Some debugger interfaces (such as ULINK) have an internal power jumper
that, in this case, should be set to in3.3-V power. Refer to debugger interface
documentation for full details. However, if your debugger interface does not have a selectable
power source, it may be necessary to install a 0-
Ω
resistor on the evaluation board to route power
to pin 1. Refer to the schematics and board drawing in the appendix of this manual for the location
of this resistor.
USB Functions
USB Overview
An FT2232 device from Future Technology Devices International Ltd manages USB-to-serial
conversion. The FT2232 is factory configured to implement a JTAG/SWD port (synchronous serial)
on channel A and a Virtual COM Port (VCP) on channel B. This feature allows two simultaneous
communications links between the host computer and the target device using a single USB cable.
Separate Windows drivers for each function are provided on the Documentation and Software CD.
A small serial EEPROM holds the FT2232 configuration data. The EEPROM is not accessible by
the LM3S2965 microcontroller.
For full details on FT2232 operation, go to www.ftdichip.com .
USB to JTAG/SWD
The FT2232 USB device performs JTAG/SWD serial operations under the control of the debugger.
A CPLD (U4) multiplexes SWD and JTAG functions and, when working in SWD mode, provides
direction control for the bidirectional data line.
Virtual COM Port
The Virtual COM Port (VCP) allows Windows applications (such as HyperTerminal) to
communicate with
UART0
on the LM3S2965 over USB. Once the FT2232 VCP driver is installed,
Windows assigns a COM port number to the VCP channel.
Serial Wire Out
The evaluation board supports the Cortex-M3 serial-wire output (SWO) trace capabilities. Under
debugger control, the CPLD can route the SWO datastream to the virtual communication port
(VCP) transmit channel. The debugger can then decode and interpret the trace information
received from the VCP. The normal VCP connection to
UART0
is interrupted when using SWO. Not
all debuggers support SWO. Refer to the Stellaris LM3S3748 data sheet for additional information
on the trace port interface unit (TPIU).
Organic LED Display
The EVB features an Organic LED (OLED) graphics display with 128 x 64 pixel resolution. OLED
is a new technology that offers many advantages over LCD display technology.
Features
„
RiT P14201 series display
„
128 columns by 96 rows
„
High-contrast (typ. 500:1)
„
Excellent brightness (120 cd/m
2
)