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Example Applications
2.6 USB Boot Loader (boot_usb)
The boot loader is a small piece of code that can be programmed at the beginning of flash to act as
an application loader as well as an update mechanism for an application running on a Tiva C Series
microcontroller, utilizing either UART0, I2C0, SSI0, or USB. The capabilities of the boot loader are
configured via the bl_config.h include file. For this example, the boot loader uses the USB Device
Firmware Upgrade (DFU) class to download an application.
Applications intended for use with this version of the boot loader should be linked to run from
address 0x2800 in flash (rather than the default run address of 0). This address is chosen to
ensure that boot loader images built with all supported compilers may be used without modifying
the application start address. Depending upon the compiler and optimization level you are using,
however, you may find that you can reclaim some space by lowering this address and rebuilding
both the application and boot loader. To do this, modify the makefile or project you use to build
the application to show the new run address and also change the APP_START_ADDRESS value
defined in bl_config.h before rebuilding the boot loader.
The USB boot loader may be demonstrated using the boot_demo1 and boot_demo2 example ap-
plications in addition to the boot_usb boot loader binary itself. Note that these are the only two
example applications currently configured to run alongside the USB boot loader but making any of
the other applications boot loader compatible is simply a matter of relinking them with the new start
address and adding a mechanism to transfer control to the boot loader when required.
The Windows device driver required to communicate with the USB boot loader can be found on
the software and documentation CD from the development kit package. It can also be found in the
Windows driver package which can be downloaded via a link from
http://www.ti.com/tiva.
A Windows command-line application, dfuprog, is also provided which illustrates how to per-
form uploads and downloads via the USB DFU protocol. The source for this application can be
found in the /ti/TivaWare_C_Series-x.x/tools directory and the prebuilt executable is available in
the package “TivaWare for C Series PC Companion Utilities” available for download via a link from
http://www.ti.com/tivaware
.
2.7 Hello World (hello)
A very simple “hello world” example. It simply displays “Hello World!” on the display and is a starting
point for more complicated applications. This example uses calls to the TivaWare Graphics Library
graphics primitives functions to update the display. For a similar example using widgets, please see
“hello_widget”.
2.8 Hibernate Example (hibernate)
An example to demonstrate the use of the Hibernation module. The user can put the microcontroller
in hibernation by pressing the select button. The microcontroller will then wake on its own after 5
seconds, or immediately if the user presses the select button again. The program keeps a count
of the number of times it has entered hibernation. The value of the counter is stored in the battery
backed memory of the Hibernation module so that it can be retrieved when the microcontroller
wakes.
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