Texas Instruments EK-LM4F232 User manual

Copyright © 2011-2017
Texas Instruments Incorporated
SW-EK-LM4F232-UG-2.1.4.178
USER’S GUIDE
EK-LM4F232 Firmware Development
Package

Copyright
Copyright © 2011-2017 Texas Instruments Incorporated. All rights reserved. Tiva and TivaWare are trademarks of Texas Instruments Instruments. ARM
and Thumb are registered trademarks and Cortex is a trademark of ARM Limited. Other names and brands may be claimed as the property of others.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semicon-
ductor products and disclaimers thereto appears at the end of this document.
Texas Instruments
108 Wild Basin, Suite 350
Austin, TX 78746
www.ti.com/tiva-c
Revision Information
This is version 2.1.4.178 of this document, last updated on February 22, 2017.
2 February 22, 2017

Table of Contents
Table of Contents
Copyright ..................................................... 2
Revision Information ............................................... 2
1 Introduction ................................................. 5
2 Example Applications ........................................... 7
2.1 Bit-Banding (bitband) ............................................ 7
2.2 Blinky (blinky) ................................................ 7
2.3 Boot Loader Demo 1 (boot_demo1) .................................... 7
2.4 Boot Loader Demo 2 (boot_demo2) .................................... 8
2.5 Boot Loader (boot_serial) .......................................... 8
2.6 USB Boot Loader (boot_usb) ........................................ 9
2.7 Hello World (hello) .............................................. 9
2.8 Hibernate Example (hibernate) ....................................... 9
2.9 Interrupts (interrupts) ............................................ 10
2.10 MPU (mpu_fault) ............................................... 10
2.11 Data Logger (qs-logger) ........................................... 10
2.12 SD card using FAT file system (sd_card) ................................. 11
2.13 Sine Demo (sine_demo) .......................................... 12
2.14 SoftUART Echo (softuart_echo) ...................................... 12
2.15 Timer (timers) ................................................ 12
2.16 UART Echo (uart_echo) ........................................... 12
2.17 uDMA (udma_demo) ............................................ 12
2.18 USB Generic Bulk Device (usb_dev_bulk) ................................. 12
2.19 USB HID Keyboard Device (usb_dev_keyboard) ............................. 13
2.20 USB MSC Device (usb_dev_msc) ..................................... 13
2.21 USB Serial Device (usb_dev_serial) .................................... 13
2.22 USB host audio example application using SD Card FAT file system (usb_host_audio) ........ 14
2.23 USB HID Keyboard Host (usb_host_keyboard) .............................. 14
2.24 USB HID Mouse Host (usb_host_mouse) ................................. 14
2.25 USB Mass Storage Class Host Example (usb_host_msc) ........................ 14
2.26 USB Stick Update Demo (usb_stick_demo) ................................ 14
2.27 USB Memory Stick Updater (usb_stick_update) ............................. 15
2.28 Watchdog (watchdog) ............................................ 15
3 Buttons Driver ............................................... 17
3.1 Introduction .................................................. 17
3.2 API Functions ................................................ 17
3.3 Programming Example ........................................... 18
4 Display Driver ................................................ 19
4.1 Introduction .................................................. 19
4.2 API Functions ................................................ 19
4.3 Programming Example ........................................... 20
IMPORTANT NOTICE ............................................... 22
February 22, 2017 3

Table of Contents
4 February 22, 2017

Introduction
1 Introduction
The Texas Instruments® Stellaris® EK-LM4F232 evaluation board is a platform that can be used
for software development and prototyping a hardware design. It can also be used as a guide for
custom board design using a Stellaris microcontroller.
The EK-LM4F232 includes a Stellaris ARM® Cortex™-M3-based microcontroller and the following
features:
Stellaris® LM4F232H5QD microcontroller
Four 20V analog inputs
3-axis analog accelerometer
On-board temperature sensor
Bright 96 x 64 16-bit color OLED display
5 user buttons
User LED
Shunt for microcontroller current consumption measurement
MicroSD card connector
USB OTG connector
On-board In-Circuit Debug Interface (ICDI)
Coin cell backup battery for Hibernate feature
Power supply option from USB ICDI connection, or OTG connection
This document describes the board-specific drivers and example applications that are provided for
this development board.
February 22, 2017 5

Introduction
6 February 22, 2017

Example Applications
2 Example Applications
The example applications show how to utilize features of the EK-LM4F232 evaluation board. Exam-
ples are included to show how to use many of the general features of the Stellaris microcontroller,
as well as the feature that are unique to this evaluation board.
A number of drivers are provided to make it easier to use the features of the EK-LM4F232. These
drivers also contain low-level code that make use of the Stellaris peripheral driver library and utili-
ties.
There is an IAR workspace file (ek-lm4f232.eww) that contains the peripheral driver library
project, along with all of the board example projects, in a single, easy-to-use workspace for use
with Embedded Workbench version 5.
There is a Keil multi-project workspace file (ek-lm4f232.uvmpw) that contains the peripheral
driver library project, along with all of the board example projects, in a single, easy-to-use
workspace for use with uVision.
All of these examples reside in the examples/boards/ek-lm4f232 subdirectory of the firmware
development package source distribution.
2.1 Bit-Banding (bitband)
This example application demonstrates the use of the bit-banding capabilities of the Cortex-M3
microprocessor. All of SRAM and all of the peripherals reside within bit-band regions, meaning that
bit-banding operations can be applied to any of them. In this example, a variable in SRAM is set to
a particular value one bit at a time using bit-banding operations (it would be more efficient to do a
single non-bit-banded write; this simply demonstrates the operation of bit-banding).
2.2 Blinky (blinky)
A very simple example that blinks the on-board LED.
2.3 Boot Loader Demo 1 (boot_demo1)
An example to demonstrate the use of a flash-based boot loader. At startup, the application will
configure the UART and USB peripherals, and then branch to the boot loader to await the start
of an update. If using the serial boot loader (boot_serial), the UART will always be configured at
115,200 baud and does not require the use of auto-bauding.
This application is intended for use with any of the three flash-based boot loader flavors (boot_serial
or boot_usb) included in the software release. To accommodate the largest of these (boot_usb),
the link address is set to 0x2800. If you are using serial, you may change this address to a 1KB
boundary higher than the last address occupied by the boot loader binary as long as you also
rebuild the boot loader itself after modifying its bl_config.h file to set APP_START_ADDRESS to
the same value.
February 22, 2017 7

Example Applications
The boot_demo2 application can be used along with this application to easily demonstrate that the
boot loader is actually updating the on-chip flash.
Note that the LM4F232 and other Blizzard-class devices also support the serial and USB boot
loaders in ROM. To make use of this function, link your application to run at address 0x0000 in flash
and enter the bootloader using the ROM_UpdateSerial and ROM_UpdateUSB functions (defined
in rom.h). This mechanism is used in the utils/swupdate.c module when built specifically targeting
a suitable Blizzard-class device.
2.4 Boot Loader Demo 2 (boot_demo2)
An example to demonstrate the use of a flash-based boot loader. At startup, the application will
configure the UART, USB and Ethernet peripherals, wait for a widget on the screen to be pressed,
and then branch to the boot loader to await the start of an update. If using the serial boot loader
(boot_serial), the UART will always be configured at 115,200 baud and does not require the use of
auto-bauding.
This application is intended for use with any of the three flash-based boot loader flavors (boot_eth,
boot_serial or boot_usb) included in the software release. To accommodate the largest of these
(boot_usb), the link address is set to 0x2800. If you are using serial or Ethernet boot loader, you
may change this address to a 1KB boundary higher than the last address occupied by the boot
loader binary as long as you also rebuild the boot loader itself after modifying its bl_config.h file to
set APP_START_ADDRESS to the same value.
The boot_demo1 application can be used along with this application to easily demonstrate that the
boot loader is actually updating the on-chip flash.
Note that the LM4F232 and other Blizzard-class devices also the support serial and USB boot
loaders in ROM. To make use of this function, link your application to run at address 0x0000 in
flash and enter the bootloader using either the ROM_UpdateUSB or ROM_UpdateSerial functions
(defined in rom.h). This mechanism is used in the utils/swupdate.c module when built specifically
targeting a suitable Blizzard-class device.
2.5 Boot Loader (boot_serial)
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 UART0 to load an
application.
The configuration is set to boot applications which are linked to run from address 0x2800 in flash.
This is higher than strictly necessary but is intended to allow the example boot loader-aware appli-
cations provided in the release to be used with any of the three boot loader example configurations
supplied (serial or USB) without having to adjust their link addresses.
Note that the LM4F232 and other Blizzard-class devices also support serial boot loaders in ROM.
8 February 22, 2017

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.
February 22, 2017 9

Example Applications
2.9 Interrupts (interrupts)
This example application demonstrates the interrupt preemption and tail-chaining capabilities of
Cortex-M4 microprocessor and NVIC. Nested interrupts are synthesized when the interrupts have
the same priority, increasing priorities, and decreasing priorities. With increasing priorities, pre-
emption will occur; in the other two cases tail-chaining will occur. The currently pending interrupts
and the currently executing interrupt will be displayed on the display; GPIO pins D0, D1 and D2 will
be asserted upon interrupt handler entry and de-asserted before interrupt handler exit so that the
off-to-on time can be observed with a scope or logic analyzer to see the speed of tail-chaining (for
the two cases where tail-chaining is occurring).
2.10 MPU (mpu_fault)
This example application demonstrates the use of the MPU to protect a region of memory from
access, and to generate a memory management fault when there is an access violation.
2.11 Data Logger (qs-logger)
This example application is a data logger. It can be configured to collect data from up to 10 data
sources. The possible data sources are:
4 analog inputs, 0-20V
3-axis accelerometer
internal and external temperature sensors
processor current consumption
The data logger provides a menu navigation that is operated by the buttons on the EK-LM4F232
board (up, down, left, right, select). The data logger can be configured by using the menus. The
following items can be configured:
data sources to be logged
sample rate
storage location
sleep modes
clock
Using the data logger:
Use the CONFIG menu to configure the data logger. The following choices are provided:
CHANNELS - enable specific channels of data that will be logged
PERIOD - select the sample period
STORAGE - select where the collected data will be stored:
•FLASH - stored in the internal flash memory
•USB - stored on a connected USB memory stick
10 February 22, 2017

Example Applications
•HOST PC - transmitted to a host PC via USB OTG virtual serial port
•NONE - the data will only be displayed and not stored
SLEEP - select whether or not the board sleeps between samples. Sleep mode is allowed
when storing to flash at with a period of 1 second or longer.
CLOCK - allows setting of internal time-of-day clock that is used for time stamping of the
sampled data
Use the START menu to start the data logger running. It will begin collecting and storing the data.
It will continue to collect data until stopped by pressing the left button or select button.
While the data logger is collecting data and it is not configured to sleep, a simple strip chart showing
the collected data will appear on the display. If the data logger is configured to sleep, then no strip
chart will be shown.
If the data logger is storing to internal flash memory, it will overwrite the oldest data. If storing to a
USB memory device it will store data until the device is full.
The VIEW menu allows viewing the values of the data sources in numerical format. When viewed
this way the data is not stored.
The SAVE menu allows saving data that was stored in internal flash memory to a USB stick. The
data will be saved in a text file in CSV format.
The ERASE menu is used to erase the internal memory so more data can be saved.
When the EK-LM4F232 board running qs-logger is connected to a host PC via the USB OTG
connection for the first time, Windows will prompt for a device driver for the board. This can be found
in /ti/TivaWare_C_Series-x.x/windows_drivers assuming you installed the software in the default
folder.
A companion Windows application, logger, can be found in the /ti/TivaWare_C_Series-x.x/tools/bin
directory. When the data logger’s STORAGE option is set to "HOST PC" and the board is connected
to a PC via the USB OTG connection, captured data will be transfered back to the PC using the
virtual serial port that the EK board offers. When the logger application is run, it will search for the
first connected EK-LM4F232 board and display any sample data received. The application also
offers the option to log the data to a file on the PC.
2.12 SD card using FAT file system (sd_card)
This example application demonstrates reading a file system from an SD card. It makes use of
FatFs, a FAT file system driver. It provides a simple command console via a serial port for issuing
commands to view and navigate the file system on the SD card.
The first UART, which is connected to the USB debug virtual serial port on the evaluation board, is
configured for 115,200 bits per second, and 8-N-1 mode. When the program is started a message
will be printed to the terminal. Type “help” for command help.
For additional details about FatFs, see the following site:
http://elm-chan.org/fsw/ff/00index_e.html
February 22, 2017 11

Example Applications
2.13 Sine Demo (sine_demo)
This example uses the floating point capabilities of the Tiva C Series processor to compute a sine
wave and show it on the display.
2.14 SoftUART Echo (softuart_echo)
This example application utilizes the SoftUART to echo text. The SoftUART is configured to use
the same pins as the first UART (connected to the FTDI virtual serial port on the evaluation board),
at 115,200 baud, 8-n-1 mode. All characters received on the SoftUART are transmitted back to the
SoftUART.
2.15 Timer (timers)
This example application demonstrates the use of the timers to generate periodic interrupts. One
timer is set up to interrupt once per second and the other to interrupt twice per second; each
interrupt handler will toggle its own indicator on the display.
2.16 UART Echo (uart_echo)
This example application utilizes the UART to echo text. The first UART (connected to the USB
debug virtual serial port on the evaluation board) will be configured in 115,200 baud, 8-n-1 mode.
All characters received on the UART are transmitted back to the UART.
2.17 uDMA (udma_demo)
This example application demonstrates the use of the uDMA controller to transfer data between
memory buffers, and to transfer data to and from a UART. The test runs for 10 seconds before
exiting.
2.18 USB Generic Bulk Device (usb_dev_bulk)
This example provides a generic USB device offering simple bulk data transfer to and from the host.
The device uses a vendor-specific class ID and supports a single bulk IN endpoint and a single bulk
OUT endpoint. Data received from the host is assumed to be ASCII text and it is echoed back with
the case of all alphabetic characters swapped.
A Windows INF file for the device is provided on the installation CD and in the
C:/ti/TivaWare_C_Series-x.x/windows_drivers directory of TivaWare releases. This INF contains
information required to install the WinUSB subsystem on WindowsXP and Vista PCs. WinUSB is a
12 February 22, 2017

Example Applications
Windows subsystem allowing user mode applications to access the USB device without the need
for a vendor-specific kernel mode driver.
A sample Windows command-line application, usb_bulk_example, illustrating how to connect to and
communicate with the bulk device is also provided. The application binary is installed as part of the
“TivaWare for C Series PC Companion Utilities” package (SW-TM4C-USB-WIN) on the installation
CD or via download from http://www.ti.com/tivaware . Project files are included to allow
the examples to be built using Microsoft Visual Studio 2008. Source code for this application can
be found in directory ti/TivaWare_C_Series-x.x/tools/usb_bulk_example.
2.19 USB HID Keyboard Device (usb_dev_keyboard)
This example application turns the evaluation board into a USB keyboard supporting the Human
Interface Device class. When the push button is pressed, a sequence of key presses is simulated
to type a string. Care should be taken to ensure that the active window can safely receive the text;
enter is not pressed at any point so no actions are attempted by the host if a terminal window is
used (for example). The status LED is used to indicate the current Caps Lock state and is updated
in response to any other keyboard attached to the same USB host system.
The device implemented by this application also supports USB remote wakeup allowing it to request
the host to reactivate a suspended bus. If the bus is suspended (as indicated on the application dis-
play), pressing the push button will request a remote wakeup assuming the host has not specifically
disabled such requests.
2.20 USB MSC Device (usb_dev_msc)
This example application turns the evaluation board into a USB mass storage class device. The
application will use the microSD card for the storage media for the mass storage device. The
screen will display the current action occurring on the device ranging from disconnected, no media,
reading, writing and idle.
2.21 USB Serial Device (usb_dev_serial)
This example application turns the evaluation kit into a virtual serial port when connected to the USB
host system. The application supports the USB Communication Device Class, Abstract Control
Model to redirect UART0 traffic to and from the USB host system.
Assuming you installed TivaWare in the default directory, a driver information (INF) file for use
with Windows XP, Windows Vista and Windows7 can be found in C:/ti/TivaWare_C_Series-
x.x/windows_drivers. For Windows 2000, the required INF file is in C:/ti/TivaWare_C_Series-
x.x/windows_drivers/win2K.
February 22, 2017 13

Example Applications
2.22 USB host audio example application using SD Card
FAT file system (usb_host_audio)
This example application demonstrates playing .wav files from an SD card that is formatted with a
FAT file system using USB host audio class. The application will only look in the root directory of
the SD card and display all files that are found. Files can be selected to show their format and then
played if the application determines that they are a valid .wav file. Only PCM format (uncompressed)
files may be played.
For additional details about FatFs, see the following site:
http://elm-chan.org/fsw/ff/00index_e.html
2.23 USB HID Keyboard Host (usb_host_keyboard)
This example application demonstrates how to support a USB keyboard attached to the evaluation
kit board. The display will show if a keyboard is currently connected and the current state of the
Caps Lock key on the keyboard that is connected on the bottom status area of the screen. Pressing
any keys on the keyboard will cause them to be printed on the screen and to be sent out the UART
at 115200 baud with no parity, 8 bits and 1 stop bit. Any keyboard that supports the USB HID BIOS
protocol should work with this demo application.
2.24 USB HID Mouse Host (usb_host_mouse)
This application demonstrates the handling of a USB mouse attached to the evaluation kit. Once
attached, the position of the mouse pointer and the state of the mouse buttons are output to the
display.
2.25 USB Mass Storage Class Host Example
(usb_host_msc)
This example application demonstrates reading a file system from a USB flash disk. It makes
use of FatFs, a FAT file system driver. It provides a simple widget-based display for showing and
navigating the file system on a USB stick.
For additional details about FatFs, see the following site:
http://elm-chan.org/fsw/ff/00index_e.html
2.26 USB Stick Update Demo (usb_stick_demo)
An example to demonstrate the use of the flash-based USB stick update program. This example
is meant to be loaded into flash memory from a USB memory stick, using the USB stick update
program (usb_stick_update), running on the microcontroller.
14 February 22, 2017

Example Applications
After this program is built, the binary file (usb_stick_demo.bin), should be renamed to the filename
expected by usb_stick_update ("FIRMWARE.BIN" by default) and copied to the root directory of a
USB memory stick. Then, when the memory stick is plugged into the eval board that is running
the usb_stick_update program, this example program will be loaded into flash and then run on the
microcontroller.
This program simply displays a message on the screen and prompts the user to press the select
button. Once the button is pressed, control is passed back to the usb_stick_update program which
is still is flash, and it will attempt to load another program from the memory stick. This shows how
a user application can force a new firmware update from the memory stick.
2.27 USB Memory Stick Updater (usb_stick_update)
This example application behaves the same way as a boot loader. It resides at the beginning of
flash, and will read a binary file from a USB memory stick and program it into another location in
flash. Once the user application has been programmed into flash, this program will always start the
user application until requested to load a new application.
When this application starts, if there is a user application already in flash (at
APP_START_ADDRESS), then it will just run the user application. It will attempt to load a
new application from a USB memory stick under the following conditions:
no user application is present at APP_START_ADDRESS
the user application has requested an update by transferring control to the updater
the user holds down the eval board push button when the board is reset
When this application is attempting to perform an update, it will wait forever for a USB memory stick
to be plugged in. Once a USB memory stick is found, it will search the root directory for a specific
file name, which is FIRMWARE.BIN by default. This file must be a binary image of the program you
want to load (the .bin file), linked to run from the correct address, at APP_START_ADDRESS.
The USB memory stick must be formatted as a FAT16 or FAT32 file system (the normal case), and
the binary file must be located in the root directory. Other files can exist on the memory stick but
they will be ignored.
2.28 Watchdog (watchdog)
This example application demonstrates the use of the watchdog as a simple heartbeat for the
system. If the watchdog is not periodically fed, it will reset the system. Each time the watchdog is
fed, the LED is inverted so that it is easy to see that it is being fed, which occurs once every second.
To stop the watchdog being fed and, hence, cause a system reset, press the select button.
February 22, 2017 15

Example Applications
16 February 22, 2017

Buttons Driver
3 Buttons Driver
Introduction ..............................................................................................17
APIFunctions ............................................................................................17
ProgrammingExample ...................................................................................18
3.1 Introduction
The buttons driver provides functions to make it easy to use the push buttons on the EK-LM4F232
evaluation board. The driver provides a function to initialize all the hardware required for the buttons,
and features for debouncing and querying the button state.
This driver is located in examples/boards/ek-lm4f232/drivers, with buttons.c containing
the source code and buttons.h containing the API declarations for use by applications.
3.2 API Functions
Functions
void ButtonsInit (void)
uint8_t ButtonsPoll (uint8_t ∗pui8Delta, uint8_t ∗pui8RawState)
3.2.1 Function Documentation
3.2.1.1 ButtonsInit
Initializes the GPIO pins used by the board pushbuttons.
Prototype:
void
ButtonsInit(void)
Description:
This function must be called during application initialization to configure the GPIO pins to which
the pushbuttons are attached. It enables the port used by the buttons and configures each
button GPIO as an input with a weak pull-up.
Returns:
None.
3.2.1.2 ButtonsPoll
Polls the current state of the buttons and determines which have changed.
February 22, 2017 17

Buttons Driver
Prototype:
uint8_t
ButtonsPoll(uint8_t *pui8Delta,
uint8_t *pui8RawState)
Parameters:
pui8Delta points to a character that will be written to indicate which button states changed
since the last time this function was called. This value is derived from the debounced state
of the buttons.
pui8RawState points to a location where the raw button state will be stored.
Description:
This function should be called periodically by the application to poll the pushbuttons. It deter-
mines both the current debounced state of the buttons and also which buttons have changed
state since the last time the function was called.
In order for button debouncing to work properly, this function should be caled at a regular
interval, even if the state of the buttons is not needed that often.
If button debouncing is not required, the the caller can pass a pointer for the pui8RawState
parameter in order to get the raw state of the buttons. The value returned in pui8RawState will
be a bit mask where a 1 indicates the buttons is pressed.
Returns:
Returns the current debounced state of the buttons where a 1 in the button ID’s position indi-
cates that the button is pressed and a 0 indicates that it is released.
3.3 Programming Example
The following example shows how to use the buttons driver to initialize the buttons, debounce and
read the buttons state.
//
// Initialize the buttons.
//
ButtonsInit();
//
// From timed processing loop (for example every 10 ms)
//
...
{
//
// Poll the buttons. When called periodically this function will
// run the button debouncing algorithm.
//
ucState = ButtonsPoll(&ucDelta, 0);
//
// Test to see if the SELECT button was pressed and do something
//
if(BUTTON_PRESSED(SELECT_BUTTON, ucState, ucDelta))
{
...
// SELECT button action
}
}
18 February 22, 2017

Display Driver
4 Display Driver
Introduction ..............................................................................................19
APIFunctions ............................................................................................19
ProgrammingExample ...................................................................................20
4.1 Introduction
The display driver offers a standard interface to access display functions on the CrystalFontz 96x64
16-bit color OLED display and is used by the Stellaris Graphics Library and widget manager. In
addition to providing the tDisplay structure required by the graphics library, the display driver
also provides an API for initializing the display.
This driver is located in examples/boards/ek-lm4f232/drivers, with cfal96x64x16.c
containing the source code and cfal96x64x16.h containing the API declarations for use by ap-
plications.
4.2 API Functions
Functions
void CFAL96x64x16Init (void)
Variables
const tDisplay g_sCFAL96x64x16
4.2.1 Function Documentation
4.2.1.1 CFAL96x64x16Init
Initializes the display driver.
Prototype:
void
CFAL96x64x16Init(void)
Description:
This function initializes the SSD1332 display controller on the panel, preparing it to display
data.
Returns:
None.
February 22, 2017 19

Display Driver
4.2.2 Variable Documentation
4.2.2.1 g_sCFAL96x64x16
Definition:
const tDisplay g_sCFAL96x64x16
Description:
The display structure that describes the driver for the Crystalfontz CFAL9664-F-B1 OLED panel
with SSD 1332 controller.
4.3 Programming Example
The following example shows how to initialize the display and prepare to draw on it using the
graphics library.
tContext sContext;
//
// Initialize the display.
//
CFAL96x64x16Init();
//
// Initialize a graphics library drawing context.
//
GrContextInit(&sContext, &g_sCFAL96x64x16);
20 February 22, 2017