COM iMX25 Linux

Linux virtual machine for development

• Please have a look at: Virtual Machine for Application Development

Building your own Kernel

Sources for the iMX25 Linux Kernel v3.2.9 / v3.2.81:

• The latest Linux Kernel source code is available on GitHub: https://github.com/dh-electronics/linux-imx25
• We recommend to use on new projects the latest v3.2.81 Linux Kernel

How to build a kernel

Get sources from Github and build the linux kernel

1. Start a terminal on Linux

2. # git clone https://github.com/dh-electronics/linux-imx25.git

3. # git checkout BRANCH (BRANCH=dev/3.2.9_dhcom or BRANCH=dev/3.2.81_dhcom)

4. # ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- make imx25_dhcom_defconfig

5. # ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- make uImage

• Your new uImage file is available in arch/arm/boot

Sources older than February 2014 Sources for the iMX25 Linux Kernel v2.6.38: Mainline Kernel version: 2.6.38 from www.kernel.org Patch to DHCOM iMX25 Linux (2014-09-29) Kernel configuration for DHCOM iMX25 Linux (2014-09-29) Sources for the iMX25 Linux Kernel v3.2.9: Mainline Kernel version: 3.2.9 from www.kernel.org Patch to DHCOM iMX25 Linux 3.2.9 (2013-09-20) Kernel configuration for DHCOM iMX25 Linux 3.2.9 (2013-03-27) How to build a kernel 1. Start a terminal on Linux 2. Copy the above mentioned source files (linux-3.x.y.tar.bz2, .config, *.patch) into our work_path 3. # cd work_path 4. # tar xfjv linux-2.6.38.tar.bz2 5. # cd work_path/linux-2.6.38 6. # patch -p1 <linux-2.6.38_DHCOM_iMX25.patch 7. # cp .config work_path/linux-2.6.38 8. # ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabi- make uImage Your new uImage file is available in work_path/linux-2.6.38/arch/arm/boot

Update the kernel with U-Boot

The linux kernel will be updated by the U-Boot flash update.

• Binary image 2.6.38 DHCOM iMX25 linux kernel (2014-09-29)
• Binary image 3.2.9 DHCOM iMX25 linux kernel (2016-02-24)
• Binary image 3.2.78 DHCOM iMX25 linux kernel (2016-03-08)

1. Copy the uImage and uImage.env file onto a microSD card with a FAT file system (you can use the 1st partition on the microSD card)

2. Insert the microSD card and start the system

3. Go to the U-Boot console by pressing BACKSPACE on a RS232 terminal (during startup)

4. update linux

Debian Rootfilesystem

Available Rootfilesystems

Please have a look at the iMX25 Downloads section.

External Documentation

• The Debian Administrator's Handbook: A reference book presenting the Debian distribution, from initial installation to configuration of services. The administration and configuration chapters apply to our Debian based root filesystems.
• Debian Documentation

Login

Debian GNU/Linux 6.0 dhcom ttymxc1 dhcom login: root Password: foo

Calibrating the touchscreen

# TSLIB_TSDEVICE=/dev/input/event0 ts_calibrate

Running example Qt Apps

# QWS_MOUSE_PROTO=Tslib:/dev/input/event0 /usr/qt/demos/demoname/demoname -qws

• Remark: To start the Qt-Browser replace demoname with browser

Shutdown

# shutdown -h now

How to create a microSD-card with a rootfilesystem on it

1. Format a microSD card like following (in linux e.g. gparted, palimpsest) with Master Boot Record partition scheme

P1 FAT (Primary partition: 100MB) P2 ext3 (Primary partition: Residual space)

2. Untar the root file system to the ext3 partition of the microSD card (Don't copy the tar archive directly to the microSD card)

Start the Console on Linux # su # chmod 755 /path/of/the/microSD_card # cd /path/of/the/microSD_card # tar xfjv path/to/RootFS/Name_of_RootFS_file.tar.bz2

Remark: If you got a *.tar.gz file so type tar xfzv ... to extract the rootfilesystem.

Busybox Rootfilesystem

Calibrating the touchscreen

TSLIB_TSDEVICE=/dev/event0 ts_calibrate

Running example Qt Apps

QWS_MOUSE_PROTO=Tslib:/dev/event0 /usr/qt/demos/demoname/demoname -qws

For the Qt-Browser change demoname to browser

Login/Shutdown system

Username:	root
Password:	n/a

halt

Kernel Userspace Interfaces to Access Hardware

Serial (UART) Interfaces

DHCOM (FF) UART 1	/dev/ttymxc1
DHCOM (BT) UART 2	/dev/ttymxc2
DHCOM (STD) UART 3	/dev/ttymxc4

I2C Interfaces

DHCOM I2C 1	/dev/i2c-1
DHCOM I2C 2	/dev/i2c-2

SPI Interfaces

DHCOM SPI 1	/dev/spidev1.0
DHCOM SPI 2	/dev/spidev2.0

Control the display brightness

echo <value> >/sys/devices/platform/imx-fb.0/backlight/imxfb-bl/brightness

value range: 0..255

Control GPIOs

DHCOM Name:	alt. DHCOM Name:	Port:	Pin:	SO-DIMM Pin#	Linux <GPIO#>
GPIO A		2	12	154	44
GPIO B		3	21	156	85
GPIO C		2	4	162	36
GPIO D		2	5	163	37
GPIO E		2	6	164	38
GPIO F		2	7	165	39
GPIO G		2	8	167	40
GPIO H		2	9	173	41
GPIO I		3	17	175	81
CIF HSYNC	GPIO J	1	10	74	10
CIF PCLK	GPIO K	1	11	72	11
CIF MCLK	GPIO L	1	8	70	8
CIF VSYNC	GPIO M	1	9	68	9
CIF D9	GPIO N	4	21	66	117
CIF D8	GPIO O	1	7	64	7
CIF D7	GPIO P	1	6	62	6
CIF D6	GPIO Q	1	31	60	31
CIF D5	GPIO R	1	30	58	30
CIF D4	GPIO S	1	29	56	29
CIF D3	GPIO T	1	28	54	28
CIF D2	GPIO U	1	27	52	27

Export

echo <GPIO#> >/sys/class/gpio/export

Set direction

echo in >/sys/class/gpio/gpioXX/direction

echo out >/sys/class/gpio/gpioXX/direction

Set value

echo 0 >/sys/class/gpio/gpioXX/value

echo 1 >/sys/class/gpio/gpioXX/value

Get value

cat /sys/class/gpio/gpioXX/value

unexport

echo <GPIO#> >/sys/class/gpio/unexport

Initialize and test CAN

Initialize:

ip link set can0 up type can bitrate 500000

Send test message via cansend (part of can-utils):

cansend can0 100#11.2233.44556677.88

Receive message via candump (part of can-utils):

candump can0

Get can-utils:

• Debian package containing can-utils (ARM)

Test display / framebuffer

fb_1Colorfill	Fills the framebuffer device with a given RGB color Syntax: fb_1Colorfill [fb (0..31)] [Display Bits (1..8)] [Red value (0..255)] [Green value (0..255)] [Blue value (0..255)]
fb_fb2BMP	Copies framebuffer device data into a 24Bit BMP-File Syntax: fb_fb2BMP [fb (0..31)] [24-Bit BMP-File]
fb_LoadBMP	Loads a 24Bit BMP-file into a 32Bit framebuffer device Syntax: fb_LoadBMP [fb (0..31)] [24-Bit BMP-File] [Display Bits (1..8)] [Transparency (0..100)]

In most common cases the "Display Bits" should be "8"

Get DH framebuffer tools:

• DH framebuffer tools v1.0 (ARM)

Additional Information

• Linux Kernel Features
• Embedded Linux Build Environment (ELBE)