Stellaris® LM4F120 LaunchPad User’s Manual
10
August 29, 2012
Functional Description
(Microcontroller, USB, Expansion, Buttons, and LED (Schematic on
page 18)
Microcontroller
The Stellaris LM4F120H5QR is a 32-bit ARM® Cortex™-M4F-based microcontroller with 256-KB
Flash memory, 32-KB SRAM, 80-MHz operation, USB Device, Hibernation module, and a wide
range of other peripherals. See the LM4F120H5QR microcontroller data sheet (order number
DS-LM4F120H5QR) for complete device details.
Most of the microcontroller signals are routed to 0.1" pitch headers. An internal multiplexer allows
different peripheral functions to be assigned to each of these GPIO pads. When adding external
circuitry, consider the additional load on the evaluation board’s power rails.
The LM4F120H5QR microcontroller is factory-programmed with a quickstart demo program. The
quickstart program resides in on-chip Flash memory and runs each time power is applied, unless
the quickstart application has been replaced with a user program.
USB Device
The Stellaris® LaunchPad includes a USB Micro-B connector to allow for USB 2.0 Device
operation. The signals shown in Table 2-1 are used for USB Device.
When connected as a USB Device, the evaluation board can be powered from either the Stellaris®
ICDI or the USB Device connectors. The user can select the power source by moving the POWER
SELECT switch (SW3) to the Device position. See the Power Management schematic on page 19
User Switches and RGB User LED
The Stellaris® LaunchPad comes with an RGB LED. This LED is used in the preloaded RGB
quickstart application and can be configured for use in custom applications.
Two user buttons are included on the board. The user buttons are both used in the preloaded
quickstart application to adjust the light spectrum of the RGB LED as well as go into and out of
hibernation. The user buttons can be used for other purposes in the user’s custom application.
The evaluation board also has a green power LED.
Table 2-2 shows how these features are connected to the pins on the microcontroller.
Table 2-1. USB Device Signals
GPIO Pin
Pin Function
USB Device
PD4
USB0DM
D-
PD5
USB0DP
D+
Table 2-2. User Switches and RGB LED Signals
GPIO Pin
Pin Function
Feature
PF4
GPIO
SW1
PF0
GPIO
SW2