Texas Instruments Stellaris LM3S3748 Manual

LM3S3748 EVALUATION KIT
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Stellaris® LM3S3748 Evaluation Kit
The Stellaris LM3S3748 Evaluation Kit provides a low-cost way to start designing
applications with Stellaris microcontrollers on a compact and versatile evaluation platform.
The evaluation kit design highlights the LM3S3748 microcontroller’s key features including
USB 2.0 full-speed (12 Mbps) controller, Analog-to-Digital Converter (ADC), and serial
interfaces. The LM3S3748 Evaluation Board (EVB) includes connectors for both embedded
USB Host and USB Device operation.
The LM3S3748 EVB can be used either as an evaluation platform or as a low-cost in-circuit
debug interface (ICDI). In ICDI mode, the on-board microcontroller is bypassed, allowing
programming or debugging of an external target.
Power to the EVB can be supplied through the DC jack, the USB Device connector, or the
USB debug interface connector. A small switch controls whether the board is bus-powered
using the USB Device connector or self-powered using the DC jack or USB debug interface
connector.
WARNING: Do not change the power mode switch while power is applied. Doing so
may damage the switch contacts.
LM3S3748 Evaluation Board
Requirements
You have a PC with a USB port, running Microsoft® Windows 2000, XP, or Vista
You have the Stellaris LM3S3748 Evaluation Kit Documentation and Software CD
Initial Board Set-Up
The initial board set-up of the LM3S3748 EVB consists of powering the board and installing
the FTDI drivers that are needed for debug communication.
Powering the EVB
The first step for the initial board set-up is to power the EVB.
1) Move the USB power mode switch (SW3) to the “SELF” position (see the figure that
follows).
Note: The switch must be placed in the “SELF” position for the initial board setup to
work correctly.

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USB Power Mode Switch (SW3)
EVB is Bus Powered
EVB is Self Powered
2) Using one of the USB cables provided in the kit, connect the mini-b (smaller) end of
the USB cable to the USB debug interface connector labeled “DEBUG USB” on the
EVB.
Note: If the USB cable is not plugged into the “DEBUG USB” connector, the board
will not be powered and you will not be able to install the FTDI drivers in the next
section.
3) Connect the other end (Type A) of the USB cable to a free USB port on your host PC.
The PC’s USB port is capable of sourcing up to 500 mA for each attached device, which is
sufficient for the evaluation board. If connecting the board through a USB hub, it must be a
powered hub.
Installing the FTDI Drivers
The next step is to install the FTDI drivers for the board. Some customers with previous
installations of the FTDI drivers may experience trouble when installing newer (2.02.04 and
later) versions of the drivers. The problem only seems to affect users of Windows XP, and not
Windows Vista. If you have any problems with the driver installation, see the
http://www.luminarymicro.com/ftdi-driver web site for information.
1) When you power the EVB using the “DEBUG USB” connector for the first time,
Windows starts the Found New Hardware Wizard and asks if Windows can connect to
Windows Update to search for software. Select “No, not this time” and then click
Next.
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2) Next, the Found New Hardware Wizard asks you from where to install the software.
Select “Install from a list or specific location (Advanced)” and click Next.
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3) Make sure the “Documentation and Software” CD that came with the evaluation kit is
in your CD-ROM drive. Select “Search for the best driver in these locations,” and
check the “Search removable media (floppy, CD-ROM…)” option. Click Next.
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4) A warning may pop up during the Hardware Installation like the one below; click
Continue Anyway.
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5) Windows finishes installing the drivers for “Stellaris Evaluation Board A.” When the
driver install is finished, the Found New Hardware Wizard window appears like the
one below. Click Finish to close the dialog box.
You have just installed the drivers for “Stellaris Evaluation Board A.” The USB device built
into the EVB is a composite USB device. After you click Finish, Windows automatically
installs a driver for the “Stellaris Evaluation Board B” part of the composite USB device.
Follow the same instructions as above to install the drivers for this device.
The Found New Hardware Wizard appears one last time. This is to install the drivers for the
“Stellaris Virtual COM Port.” Again, follow the same instructions to install the drivers for this
device.
Now all of the FTDI drivers for the LM3S3748 Evaluation Board have been installed. These
drivers give the debugger access to the JTAG interface and the host PC access to the Virtual
COM Port.
With the drivers installed, Windows automatically detects any new Stellaris boards that you
attach, and install the drivers for you.
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Quickstart Application
The LM3S3748 Evaluation Board comes preprogrammed with a quickstart application. Once
you have powered the board, this application runs automatically. You have probably already
noticed this running as you installed the drivers. A splash screen appears on the LCD for a
few seconds before the application begins.
The quickstart application provides a simple two channel oscilloscope sampling at up to 1M
samples per second. The two oscilloscope channels are differential measurement channels
which provide waveform acquisition using the LM3S3748 microcontroller’s Analog-to-
Digital Converter (ADC). The evaluation board includes an oscilloscope header that contains
the two channel differential inputs, two test point pins, and two test ground pins.
Test Point 1 is connected to the speaker input on the EVB and allows the signal for the
keyboard click to be viewed. Note that waveform capture is typically not taking place while
the keyboard is being serviced so the click may not be seen on the waveform display for every
keypress.
Test Point 2 is connected to the output of a PWM generator set to drive a 1KHz square wave.
Test Ground
Channel 1-
Channel 1+
Test Point 1
Test Point 2
Channel 2+
Channel 2-
Test Ground
The EVB has a four-way navigation switch with press-to-select functionality that is used to
configure the oscilloscope. The navigation switch is labeled “NAVIGATE” on the board.
Rocking the control in the desired direction sends “up,” “down,” “left,” or “right” messages to
the application and pressing on the center sends the “select” message.
Controls and settings are arranged into groups by function such as display settings, trigger
settings, file operations, and setup choices. These groups are accessed by pressing “select” to
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display the main menu. With the menu displayed, use “up” and “down” to select between the
available groups. When the desired group is highlighted, press “select” once again to dismiss
the menu.
Controls from the currently selected group are shown in the bottom portion of the LCD. Use
“up” and “down” to cycle through the controls in the group and “left” and “right” to change
the value of, or select the action associated with, the control which is currently displayed.
Using the oscilloscope to view Test Point 1 and Test Point 2:
1) Connect Test Point 1 to Channel 1+.
2) Connect Test Ground to Channel 1-.
3) Connect Test Point 2 to Channel 2+.
4) Connect Test Ground to Channel 2-. The connections should look like the graphic
below.
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USB Host Connector
USB Device Connector
Stellaris
LM3S3748
Microcontroller
MicroSD card slot Oscilloscope terminals
Reset switch
USB interface
for Debugger
JTAG/SWD
input and
output
34-pin I/O
break-out
header
Status LED
34-pin I/O break-
out header Speaker Navigation switch with press-to-select
5 VDC supply
input
LCD Panel
USB Power
Mode Switch
Oscilloscope leads connected to test points
5) The test point signals should now be visible on the LCD. To modify the volts per
division and time per division options, follow the additional steps below.
6) Press “select” to bring up the main menu, navigate to highlight the “Display” group,
and press “select” again. The “Display” group will be displayed at the bottom of the
LCD.

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Note: The “Display” group is the default active group after power-up.
7) Press “up” or “down” until the “Timebase” option is selected and then press “left” or
“right” to modify the amount of time per division.
8) Press “up” or “down” until the “Ch1 Scale” or “Ch2 Scale” option is selected and then
press “left” or “right” to modify the number of volts per division for that channel.
USB Device Mode
The quickstart oscilloscope application can connect to a Windows host machine via USB
where a companion application running on the PC can be used to control the oscilloscope and
display and save the waveforms. In this mode, the LM3S3748 EVB will be operating in USB
device mode.
The first step is to install the necessary USB drivers on the PC.
1) Disconnect the USB cable from the USB connector labeled “DEBUG USB” if
connected.
2) Move the USB power mode switch (SW3) to the “BUS” position.
3) Connect the mini-b (smaller) end of the USB cable to the USB device connector
labeled “USB DEVICE” on the EVB. Connect the other end (Type A) to a free USB
port on your host PC.
4) Windows starts the Found New Hardware Wizard and asks if Windows can connect to
Windows Update to search for software. Select “No, not this time” and then click
Next.