book

GNU/Linux Rapid Embedded Programming

by Rodolfo Giometti

March 2017

Intermediate to advanced

732 pages

15h 24m

English

Packt Publishing

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What this book covers
Software prerequisiteHardware prerequisite

Codes and command linesKernel and logging messagesFile modificationsSerial & network connectionsOther conventions
Downloading the example codeDownloading the color images of this bookErrataPiracyQuestions
Embedded world terms
The BeagleBone BlackThe SAMA5D3 XplainedThe Wandboard
Setting up the host machineBasic toolsThe cross-compilerSetting up the BeagleBone BlackSerial console for the BeagleBone BlackU-Boot (with MLO)Linux kernel for the BeagleBone BlackDebian 8 (jessie) for the BeagleBone BlackSetting up the SAMA5D3 XplainedSerial console for SAMA5D3 XplainedU-Boot (with boot.bin)Linux kernel for SAMA5D3 XplainedDebian 8 (jessie) for SAMA5D3 XplainedSetting up the WandboardSerial console for the WandboardU-Boot (with SPL)Linux kernel for the WandboardDebian 8 (jessie) for the Wandboard
BeagleBone Black - USB, networking, and overlaysSAMA5D3 Xplained - USB and networkingWandboard - USB and networking (wired and wireless)Common settings
Basic OS managementFile manipulation and Coecho and catddgrep and egreptr and sedhead and tailod and hexdumpfilestringsstracePackage managementSearching a software packageInstalling a packageapt-get and friends versus aptitudeThe deb filesManaging the kernel messages
The environmentManaging the storage devicesMMCManaging the flashGPIO managementAccessing an I2C deviceLoading files from the networkThe kernel command line
The C compilerNative and foreign machine architectureCompiling a C programThe native compilationThe cross-compilationCompiling a kernel module
Recompiling the kernelThe device tree
Char, block, and net devicesModules versus built-in devicesThe modutilsWriting our own device driver
The /dev directoryThe tmpfsThe procfsThe sysfs
Exporting an NFS on the hostSetting up the kernel to mount an NFSU-Boot and the kernel command line to use a NFSDeveloping into an NFS
Executing a programEntering into an ARM rootfs tree
Setting up the system
Useful and ready-to-use daemonsSystem daemons managementsyslogdsyslogd in Bashsyslogd in Csyslogd in PHPsyslogd in PythoncronxinetdsshdApacheMySQLMySQL in BashMySQL in CMySQL in PHPMySQL in Python
Managing a LED in PHPThe LAMP solutionThe built-in server solutionManaging a LED in PythonManaging a LED in Bash
A daemon in CA daemon in PHPA daemon in PythonA daemon in Bash
MTD versus block devicesWhat is an MTD device?Managing an MTD deviceFilesystems for flash memoriesJFFS2 versus UBIFSBuilding a JFFS2 filesystemBuilding a UBIFS filesystem
Using the default configurationAdding a (quasi) LAMP systemAdding a custom package
Using the default recipeAdding the graphic supportAdding a custom recipe
What is a GPIO line?GPIOs lines on the BeagleBone BlackGPIOs on the SAMA5D3 XplainedGPIOs on the Wandboard
BashC
PHPPython
An input device using GPIOsLEDs and triggers
What are TTY, serial, and UART lines?The electrical linesTTYs on the BeagleBone BlackTTYs on the SAMA5D3 XplainedTTYs on the Wandboard
Distance sensorRFID LF reader
What is the universal serial bus?The electrical linesUSB ports on the BeagleBone BlackUSB ports on the SAMA5D3 XplainedUSB ports on the Wandboard
Acting as a hostActing as a deviceThe Multi gadgetThe configfs gadget
Accessing as a host
What is the Inter-Integrated Circuit bus?The electrical linesI2C ports on the SAMA5D3 XplainedI2C ports on the Wandboard
EEPROM, ADC and IO ExpanderEEPROMADCIO ExpanderThe temperature/humidity and pressure sensorsSerial port
Writing data in CReading data in Python
What is the Serial Peripheral Interface bus?The electrical linesSPI ports on the BeagleBone BlackSPI ports on the SAMA5D3 XplainedSPI ports on the Wandboard
LCD displaySerial port
Exchanging data in CExchanging data in Python
What is the 1-Wire Bus?The electrical lines1-Wire ports on the BeagleBone Black1-Wire ports on the SAMA5D3 Xplained1-Wire ports on the Wandboard
Using the GPIO interfaceUsing an external controller
What is an Ethernet network device?Electrical linesEthernet port on the BeagleBone BlackEthernet ports on the SAMA5D3 XplainedEthernet port on the Wandboard
A simple TCP client/server applicationUsing ready-to-use networking tools
What is a wireless network device?The electrical linesWLAN device on the BeagleBone BlackWLAN device on the SAMA5D3 XplainedWLAN device on the Wandboard
Pluggable external WLAN devicesThe Wi-Fi operation modes
What is the CAN bus?The electrical linesCAN ports on the BeagleBone BlackCAN ports on the SAMA5D3 XplainedCAN ports on the Wandboard
Using the on-board controllerUsing an external controller
What is a sound device?The electrical linesSound on the BeagleBone BlackSound on the SAMA5D3 XplainedSound on the Wandboard
The ALSA utilsMadplayMplayerSox
Adding an audio codecA simple oscilloscope
What is a video device?The electrical linesVideo on the BeagleBone BlackVideo on the SAMA5D3 XplainedVideo on the Wandboard
Streaming video over the WebCapturing motion
What is an analog-to-digital converter device?The electrical linesADCs on the BeagleBone BlackADCs on the SAMA5D3 XplainedADCs on the Wandboard
What is a PWM device?The electrical linesPWMs on the BeagleBone BlackPWMs on the SAMA5D3 XplainedPWMs on the Wandboard
Digital sensorsWater sensorInfrared sensor
Moisture sensorPressure sensorLight sensor
Z-Wave controllersThe Z-Wave wall plug sensorThe Z-Wave multi sensor

Content preview from GNU/Linux Rapid Embedded Programming

Getting access to SPI devices

Now, we are ready to manage real SPI devices. We can find tons of supported devices in Linux's tree that are usually grouped according to their specific operations in complete analogy to the I²C case.

In the next section, we will see several different kinds of devices all connected to the main CPU through the SPI bus. Also, we will use different embedded kits to test them, but as said earlier, every command can be easily repeated on every GNU-/Linux-based boards with a similar configuration.

LCD display

As the first example, we will use the following tiny LCD display, which can be used in simple applications because it's cheap and well supported by BeagleBone Black's kernel: