CM-T3517: Linux: Debian
Contents
Overview
The example run-time Linux filesystem image for CM-T3517 is based on Debian GNU/Linux Sid. The CompuLab Linux package for CM-T3517 includes ready to run NAND flash image, Linux kernel configuration and source code patches and an archive of the root filesystem, used to create the image.
The default Debian Sid Linux image takes approximately 170 megabytes of flash space, and includes more than 400 software packages. Among them:
- Core system
- Debian package management system
- X11 Windowing System
- Fluxbox desktop manager
- Netsurf web browser
- Samba connectivity suite
- SSH and FTP server and client
The Getting started with Linux on CM-T3517 page provides a brief introduction on how to install the run-time Linux image. This article describes package structure and peripheral device options specific to the CM-T3517.
CM-T3517 specific settings
Connection and Logging In
Use the following usernames and passwords to login:
Account with administrative privileges:
User: root Password: 111111
Regular user account:
User: user Password: 111111
In addition to these accounts CM-T3517 allows anonymous FTP access. To login into the Linux system, you may use a serial console (ttyS2) at 115200 bps, or connect through the network, or use a keyboard and DVI/LCD display (tty1, tty2, tty3).
Networking
To configure networking, edit /etc/network/interfaces, /etc/udev/rules.d/70-persistent-net.rules, /etc/resolv.conf, /etc/hostname and /etc/hosts. For more information about Debian Linux network configuration read Network setup chapter in the Debian Reference.
Consoles
Linux file system image is designed to suit different kernel versions and configurations. Therefore, during the operating system startup, consoles at several serial ports and DVI display are enabled. Some of these devices may not be supported, either because of kernel versions incompatibilities, or because the kernel was not configured to support these devices. When the console is enabled for such a device, the following or similar message can appear on active console:
INIT: Id "T0" respawning too fast: disabled for 5 minutes
This is not an error message, it is just a warning that can be eliminated by editing /etc/inittab file.
X Windows system
CompuLab distribution contains full featured X Windows system with Fluxbox window manager. Before starting X Windows, connect USB mouse and keyboard to the system. You can run X Windows by typing startx.
Audio
CM-T3517 uses the TLV320AIC23B (TI) audio codec. The audio drivers are modularized if you use default CM-T3517 configuration. To automatically load the audio driver on Linux boot, "snd-soc-cm-t3517" has to be added to the /etc/modules. If the audio driver is not loaded, the following command will load the audio driver and enable audio support:
modprobe snd-soc-cm-t3517
More information about Linux audio subsystem can be found at ALSA project official website.
Touchscreen
CM-T3517 uses the TSC2046 (TI) touchscreen controller. The touchscreen driver is modularized if you use default CM-T3517 configuration and is loaded by udev automatically on Linux boot. If the touchscreen driver is not loaded, the following command will load the touchscreen driver:
modprobe ads7846
The X Windows system of CM-T3517 uses tslib X server input driver to get the input from the touchscreen.
Touchscreen calibration
Touchscreen calibration can be performed with ts_calibrate utility available in package libts-bin. To calibrate the touchscreen:
- Make sure X Server is not running
- Make sure the touchscreen driver is loaded as described in Touchscreen section
- Set the TSLIB_TSDEVICE system variable:
export TSLIB_TSDEVICE=/dev/input/by-path/platform-omap2_mcspi.1-event
- Run ts_calibrate utility. For proper calibration you are required to touch the touchscreen corners and center in the following order: top-left, top-right, bottom-right, bottom-left, center. The calibration results are saved to file /etc/pointercal.
- Use ts_test utility to test the calibration results.
MMC/SD
The support for MMC/SD card on CM-T3517 is built into the Linux kernel. To mount the memory card, monitor /proc/partitions to see what partitions were detected on the MMC/SD card. For example, suppose MMC/SD partition you'd like to mount is mmcblk0p1 then:
if [ ! -d /mnt/mmcblk0p1 ]; then mkdir /mnt/mmcblk0p1; fi mount /dev/mmcblk0p1 /mnt/mmcblk0p1
Software Management
Debian Linux image for CM-T3517 includes all the information required to use Debian package management utilities. You can use apt-get and dpkg out of the box.
