CM-T335: Linux: Debian Legacy
Contents
Overview
The example run-time Linux filesystem image for the CompuLab CM-T335 System-on-Module / Computer-on-Module is based on Debian GNU/Linux Sid. The CompuLab Linux package for CM-T335 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 includes more than 400 software packages. Among them:
- Core system
- Debian package management system
- X11 Windowing System
- Enlightenment desktop manager
- Netsurf web browser
- Samba connectivity suite
- SSH and FTP server and client
- ALSA configuration and usage utilities
- CAN Bus utilities
- Bluetooth tools and daemons
The Getting started with Linux on CM-T335 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-T335.
Using Debian Linux on CM-T335
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-T335 allows anonymous FTP access. To login into the Linux system, you may use a serial console (ttyO0) at 115200 bps, or connect through the network, or use a keyboard and DVI/LCD display (tty1, tty2, tty3, tty4).
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
The 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/LCD 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
The CompuLab distribution contains full featured X Windows system with Enlightenment 17 window manager. Before starting X Windows, connect USB mouse and keyboard to the system. You can run X Windows by typing startx.
Enlightenment 17 window manager has a built in configuration set up to work best with phones, tablets and similar devices. To activate the "touchscreen" profile, enter Main->Settings Panel->Settings->Profiles. Select the Touchscreen profile.
To switch back to the standard profile, please see the Known Issues article.
Software Management
The Debian Linux image for CM-T335 includes all the information required to use Debian package management utilities. You can use apt-get and dpkg out of the box.
Touchscreen
Touchscreen calibration
The supported touchscreen devices can be accessed through symbolic link /dev/input/touchscreen.
The symlink is created by udev rules defined in /etc/udev/rules.d/10-touchscreen.rules.
Calibration utilities require proper setting of TSLIB_TSDEVICE system variable (pointing to the touchscreen device special file).
This is done automatically by the /etc/profile.d/tslib.sh script.
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
- 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.
Bluetooth
CM-T335 features Bluetooth 4.0 interface. Following sections describe the initialization and simple use cases of Bluetooth device.
Host Controller Interface (HCI) Initialization
- Attach the ttyO1 serial port to the HCI Bluetooth subsystem:
root@cm-debian:~# hciattach -s 115200 /dev/ttyO1 texas 3000000 Found a Texas Instruments' chip! Firmware file : /lib/firmware/TIInit_7.6.15.bts Loaded BTS script version 1 texas: changing baud rate to 3000000, flow control to 1 Bluetooth: HCI UART driver ver 2.2 Bluetooth: HCI H4 protocol initialized Bluetooth: HCI BCSP protocol initialized Bluetooth: HCILL protocol initialized Device setup complete
- Run HCI device configuration utility to retrieve detailed information about the Bluetooth device:
root@cm-debian:~# hciconfig -a
hci0: Type: BR/EDR Bus: UART
BD Address: C4:ED:BA:3E:86:42 ACL MTU: 1021:4 SCO MTU: 180:4
UP RUNNING PSCAN
RX bytes:928 acl:0 sco:0 events:42 errors:0
TX bytes:1452 acl:0 sco:0 commands:42 errors:0
Features: 0xff 0xfe 0x2d 0xfe 0xdb 0xff 0x7b 0x87
Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3
Link policy: RSWITCH HOLD SNIFF PARK
Link mode: SLAVE ACCEPT
Name: 'cm-debian-0'
Class: 0x4a0100
Service Classes: Networking, Capturing, Telephony
Device Class: Computer, Uncategorized
HCI Version: 4.0 (0x6) Revision: 0x0
LMP Version: 4.0 (0x6) Subversion: 0x1f29
Manufacturer: Texas Instruments Inc. (13)
A2DP Headphones
- Scan for available devices to find out Headphones BT device address:
root@cm-debian:~# hcitool scan Scanning ... 00:07:A4:F2:B3:CB Motorola HT820
- Add new PCM device by editing /etc/asound.conf:
pcm.btheadphones {
type plug
slave {
pcm {
type bluetooth
device 00:07:A4:F2:B3:CB
profile "auto"
}
}
hint {
show on
description "BT Headphones"
}
}
ctl.btheadphones {
type bluetooth
}
- List device names to ensure correct settings in /etc/asound.conf:
root@cm-debian:~# aplay -L
null
Discard all samples (playback) or generate zero samples (capture)
btheadphones
BT Headphones
default:CARD=cmt335
cm-t335,
Default Audio Device
sysdefault:CARD=cmt335
cm-t335,
Default Audio Device
- Put the headphones in the pairing mode and launch bluez-simple-agent application and provide device PIN code on request:
root@cm-debian:~# bluez-simple-agent hci0 00:07:A4:F2:B3:CB RequestPinCode (/org/bluez/1194/hci0/dev_00_07_A4_F2_B3_CB) Enter PIN Code: 0000 Release New device (/org/bluez/1194/hci0/dev_00_07_A4_F2_B3_CB)
- Launch aplay playback tool:
root@cm-debian:~# aplay -D btheadphones <audio-file.wav>
Obex FTP service
The OBject EXchange protocol (OBEX) can be used to exchange all kind of objects like files, pictures, calendar entries (vCal) and business cards (vCard) over bluetooth, IrDA, USB and serial cable links. CM-T335 Linux example root file system contains file transfer utility for devices that use the OBEX protocol. Following examples demonstrate its usage with mobile phone device.
- Enable bluetooth on the phone. On CM-T335, scan for available devices to find out phone's BT address:
root@cm-debian:~# hcitool scan Scanning ... 00:15:2A:20:63:94 Nokia 6230i
- Ensure the phone supports Obex FTP service:
root@cm-debian:~# sdptool search FTP
Inquiring ...
Searching for FTP on 00:15:2A:20:63:94 ...
Service Name: OBEX File Transfer
Service RecHandle: 0x100de
Service Class ID List:
"OBEX File Transfer" (0x1106)
Protocol Descriptor List:
"L2CAP" (0x0100)
"RFCOMM" (0x0003)
Channel: 10
"OBEX" (0x0008)
Language Base Attr List:
code_ISO639: 0x656e
encoding: 0x6a
base_offset: 0x100
Profile Descriptor List:
"OBEX File Transfer" (0x1106)
Version: 0x0100
- Pair the device - provide PIN code upon request and confirm permission request on the phone:
root@cm-debian:~# bluez-simple-agent hci0 00:15:2A:20:63:94 RequestPinCode (/org/bluez/1285/hci0/dev_00_15_2A_20_63_94) Enter PIN Code: 1937 Release New device (/org/bluez/1285/hci0/dev_00_15_2A_20_63_94)
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You can launch bluez-simple-agent with no parameters. The agent is tracking requests to all bluetooth devices and triggers pin code confirmation when needed. |
- List phone's root folder:
root@cm-debian:~# obexftp -b 00:15:2A:20:63:94 --list
Browsing 00:15:2A:20:63:94 ...
Connecting..\done
Tried to connect for 579ms
Receiving "(null)".../<?xml version="1.0"?>
<!DOCTYPE folder-listing SYSTEM "obex-folder-listing.dtd"
[ <!ATTLIST folder mem-type CDATA #IMPLIED> ]>
<folder-listing version="1.0">
<folder name="EXTENTSION" user-perm="RW" mem-type="MMC"/>
<folder name="Images" created="19800101T000000" user-perm="R" mem-type="DEV"/>
<folder name="Video clips" created="19800101T000000" user-perm="R" mem-type="DEV"/>
<folder name="Music files" created="19800101T000000" user-perm="R" mem-type="DEV"/>
<folder name="Themes" created="19800101T000000" user-perm="RW" mem-type="DEV"/>
<folder name="Graphics" created="19800101T000000" user-perm="R" mem-type="DEV"/>
<folder name="Tones" created="19800101T000000" user-perm="R" mem-type="DEV"/>
<folder name="Recordings" created="19800101T000000" user-perm="R" mem-type="DEV"/>
</folder-listing>
done
Disconnecting..-done
- Transfer a file from CM-T335 to the phone:
root@cm-debian:~# obexftp -b 00:15:2A:20:63:94 --put test_file.txt Browsing 00:15:2A:20:63:94 ... Connecting..\done Tried to connect for 380ms Sending "test_file.txt"...|done Disconnecting../done
- Retrieve a file from the phone to CM-T335:
root@cm-debian:~# obexftp -b 00:15:2A:20:63:94 --get test_file.txt Browsing 00:15:2A:20:63:94 ... Connecting..\done Tried to connect for 267ms Receiving "test_file.txt".../done Disconnecting..-done
Wireless local area network (WLAN)
The CM-T335 features 802.11b/g/n wireless interface, implemented with the TI WL1271 Wireless module.
WLAN Initialization
- The WL12xx WLAN driver gets loaded automatically. Make sure that the WLAN driver is loaded:
root@cm-debian:~# lsmod | grep wl12xx_spi wl12xx_spi 4527 0 wl12xx 167292 1 wl12xx_spi
If the WLAN driver has not been loaded automatically, it can be loaded manually:
root@cm-debian:~# modprobe wl12xx_spi cfg80211: Calling CRDA to update world regulatory domain wl1271: loaded
- iwconfig command from wireless-tools package can be used to retrieve detailed information about WLAN interfaces:
root@cm-debian:~# iwconfig wlan0
wlan0 IEEE 802.11abgn ESSID:off/any
Mode:Managed Access Point: Not-Associated Tx-Power=0 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Encryption key:off
Power Management:on
- WLAN interface activating:
root@cm-debian:~# ifconfig wlan0 up wl1271: firmware booted (Rev 6.3.0.0.77)
- Sample WLAN scanning:
root@cm-debian:~# iwlist wlan0 scan
The output will show the list of Access Points and Ad-Hoc cells in range. For more information about connecting to wireless networks and tuning WLAN interfaces refer to “wpa_supplicant” and “wireless-tools” man pages.
WL12xx calibration tool
Calibration of TI WL12xx wireless device is needed for generation of specific radio configuration parameters and saving into the NVS file. The NVS file is then used by the wl12xx driver.
The CM-T335 Linux package contains the statically compiled calibrator utility from ti-utils support package for WL12xx. For more details please read OMAP Wireless Connectivity Calibration Proccess NLCP article.
Example of reading WLAN MAC address stored in NVS file:
root@cm-debian:~# ./calibrator get nvs_mac /lib/firmware/ti-connectivity/wl1271-nvs.bin MAC addr from NVS: de:ad:be:ef:00:00
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The CM-T335 WLAN MAC address is initialized from the chip fuse, not from NVS file. |
Controller–area network (CAN)
The CM-T335 features a TI DCAN Controller Area Network (DCAN), integrated into the Sitara AM335X SoC. The TI DCAN module supports bitrates up to 1 Mbit/s and is compliant to the CAN 2.0B protocol specification.
Loading CAN modules
If the D_CAN driver and/or CAN protocols (Raw and Broadcast Manager) compiled as module(s), they must be loaded prior to enabling CAN interface.
- Load Raw CAN protocol module:
root@cm-debian:~# modprobe can-raw can: raw protocol (rev 20090105)
- Load Broadcast Manager CAN protocol module:
root@cm-debian:~# modprobe can-bcm can: broadcast manager protocol (rev 20090105 t)
- Load D_CAN driver module:
root@cm-debian:~# modprobe d_can_platform CAN bus driver for Bosch D_CAN controller 1.0 d_can d_can.0: device registered (irq=52, irq_obj=53) d_can d_can.1: device registered (irq=55, irq_obj=56)
For information on enabling CAN kernel support, please, see the Linux Kernel for CM-T335 page.
CAN interface configuration
It is recommended configure the CAN interface, with the iproute2 utilities.
- To make sure the right ip utility is used, run:
root@cm-debian:~# ip -V ip utility, iproute2-ss100519
- Configure the CAN interface bit-rate to 125 Kbits/sec (values of up to 1Mbit/sec are supported):
root@cm-debian:~# ip link set can0 type can bitrate 125000
- Enable the CAN interface:
root@cm-debian:~# ip link set can0 up d_can d_can.0: can0: setting CAN BT = 0x518
Send/Receive packets
Use cansend and candump utilities to send and receive packets via CAN interface.
- Send standard CAN frame (on the first device):
root@cm-debian:~# cansend can0 111#1122334455667788
- Send extended CAN frame (on the first device):
root@cm-debian:~# cansend can0 11111111#1122334455667788
- Dump all received data frames as well as error frames (on the second device):
root@cm-debian:~# candump any,0:0,#FFFFFFFF can0 111 [8] 11 22 33 44 55 66 77 88 can0 11111111 [8] 11 22 33 44 55 66 77 88
GPIO access
Linux provides simple and convenient GPIO access via sysfs interface. A GPIO should be exported using /sys/class/gpio/export. After the GPIO is exported it is possible to change its direction and value using /sys/class/gpio/gpioX/direction and /sys/class/gpio/gpioX/value attributes.
Example
The following example demonstrates how to configure GPIO 64 as output and set value to high:
echo 64 > /sys/class/gpio/export echo out > /sys/class/gpio/gpio64/direction echo 1 > /sys/class/gpio/gpio64/value
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The above example assumes that the corresponding pin is set to mux mode 7 and the GPIO 64 is not requested in the Linux kernel. |
Graphics SDK
The CM-T335 Linux package contains pre-built and ready to run SGX functionality demo programs.
- The SGX configuration script must be run on CM-T335 before first use:
root@cm-debian:~# /etc/init.d/335x-demo
- The SGX kernel modules must be loaded prior running the demos:
root@cm-debian:~# /etc/init.d/rc.pvr start
Running Graphics SDK OpenGL ES1.x Demos
- To run OpenGL ES1.x demos, perform the following:
root@cm-debian:~# cd /opt/gfxsdkdemos/ogles root@cm-debian:/opt/gfxsdkdemos/ogles# ./OGLESEvilSkull
This will execute the OGLESEvilSkull demo. Press ‘q’ on the CM-T335 console to stop the demo execution.
Running Graphics SDK OpenGL ES2.0 Demos
- To run OpenGL ES2.x demos, perform the following:
root@cm-debian:~# cd /opt/gfxsdkdemos/ogles2 root@cm-debian:/opt/gfxsdkdemos/ogles2# ./OGLES2FilmTV
This will execute the OGLESFilmTV demo. Press ‘q’ on the CM-T335 console to stop the demo execution.
