TS-7553-V2

Note:

The TS-7553-V2 is currently in engineering sample phase. This means software and features are very likely to change as the TS-7553-V2 is currently under heavy development. There may also be some features that are currently not implemented or not fully tested, please see the Revisions and changes for more information.

TS-7553-V2

File:Ts-7553-V2.jpg
Product Page
Documentation
Schematic
Mechanical Drawing
FTP Path
Processor
Freescale i.MX286
454MHz ARM9
CPU Datasheet
RAM
128MB or 256MB DDR2
DIO
16x DIO
External Interfaces
USB 2.0 1 host 1 OTG
1x 10/100 Ethernet
2x CAN ports
5x UARTs
Internal Storage Media
2x SD
1x 2GB NAND
Power Requirements
8-28VDC
Operates around 1.1W
Runs as low as 0.6W

Overview

Note:

This product has not been released as a standard product at this time. Information contained within this manual may be incorrect and is subject to change. Additionally, the software currently available for the TS-7553-V2 has not been finalized and is subject to change at any time

The TS-7553-V2 Rev. A has not been officially released as a standard product, it is currently in sampling phase. This is a small embedded board with a Freescale i.MX286 454Mhz ARM9 CPU with 128-256MB DDR2.

Getting Started

A Linux PC is recommended for development, and will be assumed for this documentation. For users in Windows or OSX we recommend virtualizing a Linux PC. Most of our platforms run Debian and if there is no personal distribution preference this is what we recommend for ease of use.

• Debian.org

Virtualization

• Virtualbox (Windows or OSX hosts)
• VMware Player
• Parallels (OSX)

Suggested Linux Distributions

• Debian
• Ubuntu

It may be possible to develop using a Windows or OSX system, but this is not supported. Development will include accessing drives formatted for Linux and often Linux based tools.

Booting up the board

WARNING:

Be sure to take appropriate Electrostatic Discharge (ESD) precautions. Disconnect the power source before moving, cabling, or performing any set up procedures. Inappropriate handling may cause damage to the board.

The TS-7553-V2 has an input voltage range of 8v to 28v DC or 24v AC through the main power connector which offers screw terminals for secure wiring. The TS-7553-V2 will require approximately 1.4W at idle. An ideal power supply for the TS-7553-V2 will allow up to 5W to allow peripherals to be powered as well.

Once you have applied power you should look for console output. The first output is from the bootrom:

HTLLCLLC

U-Boot 2014.10-g5bd269d (Nov 18 2015 - 12:26:21)

CPU:   Freescale i.MX28 rev1.2 at 454 MHz
BOOT:  SSP SPI #2, master, 3V3 NOR
I2C:   ready
SPI:   ready
DRAM:  256 MiB
MMC:   MXS MMC: 0, MXS MMC: 1
SF: Detected N25Q64 with page size 256 Bytes, erase size 4 KiB, total 8 MiB
In:    serial
Out:   serial
Err:   serial
Net:   FEC0 [PRIME]
gpio: pin 857 (gpio 857) value is 1
Booting from the SD Card ...
** File not found /boot/boot.ub **
** File not found /boot/ts7553-fpga.vme **
3212744 bytes read in 1020 ms (3 MiB/s)
21333 bytes read in 96 ms (216.8 KiB/s)
## Booting kernel from Legacy Image at 42000000 ...
   Image Name:   Linux-3.14.28-g8f0995c
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    3212680 Bytes = 3.1 MiB
   Load Address: 40008000
   Entry Point:  40008000
   Verifying Checksum ... OK
## Flattened Device Tree blob at 41000000
   Booting using the fdt blob at 0x41000000
   Loading Kernel Image ... OK
   Loading Device Tree to 4fb4e000, end 4fb56354 ... OK

Starting kernel ...


Welcome to Debian GNU/Linux 8 (jessie)!

[ SKIP ] Ordering cycle found, skipping LSB: RPC portmapper replacement
         Expecting device dev-ttyAMA0.device...
[  OK  ] Reached target Remote File Systems (Pre).
...
[  OK  ] Started Update UTMP about System Runlevel Changes.

Debian GNU/Linux 8 ts7553 ttyAMA0

ts7553 login:

The i.MX28 internal bootrom prints out the strings of letters to indicate various stages of its internal process. The U-Boot build date reflects when U-Boot was built and serves as a revision indicator. A change to the kernel or filesystem will not affect this date.

Get a Console

Serial Console

The TS-7553-V2 includes a USB device port, this uses a 8051 based microcontroller to create a serial device on a host PC. The serial console is provided through this port at 115200 baud, 8n1, with no flow control.

Console from Linux

There are many serial terminal applications for Linux, three common used applications are picocom, screen, and minicom. These examples demonstrate all three applications and assume that the serial device is "/dev/ttyUSB0" which is common for USB adapters. Be sure to replace the serial device string with that of the device on your workstation.

picocom is a very small and simple client.

sudo picocom -b 115200 /dev/ttyUSB0

screen is a terminal multiplexer which happens to have serial support.

sudo screen /dev/ttyUSB0 115200

Or a very commonly used client is minicom which is quite powerful but requires some setup:

sudo minicom -s

• Navigate to 'serial port setup'
• Type "a" and change location of serial device to "/dev/ttyUSB0" then hit "enter"
• If needed, modify the settings to match this and hit "esc" when done:

     E - Bps/Par/Bits          : 115200 8N1
     F - Hardware Flow Control : No
     G - Software Flow Control : No

• Navigate to 'Save setup as dfl', hit "enter", and then "esc"

Console from Windows

Putty is a small simple client available for download here. Open up Device Manager to determine your console port. See the putty configuration image for more details.

U-Boot

U-Boot is used on this device as the bootloader to launch the full operating system. When the i.MX28 processor starts, it loads U-Boot from the on-board SPI flash. This allows creation of a custom boot image on either the SD, eMMC, NFS, or USB. U-Boot is a general purpose bootloader that is capable of booting into common Linux distributions, Android, Windows, or custom software OSes.

On a normal boot the output will be similar to this:

HTLLCLLC

U-Boot 2014.10-g4d36657 (Dec 07 2016 - 12:19:27)

CPU:   Freescale i.MX28 rev1.2 at 454 MHz
BOOT:  SSP SPI #2, master, 3V3 NOR
I2C:   ready
SPI:   ready
DRAM:  256 MiB
MMC:   MXS MMC: 0, MXS MMC: 1
SF: Detected IS25LQ016B with page size 256 Bytes, erase size 4 KiB, total 2 MiB

In:    serial
Out:   serial
Err:   serial
Net:   FEC0 [PRIME]
NO CHRG jumper is set, not waiting for SuperCaps to charge
Booting from the SD Card ...
** File not found /boot/boot.ub **
3336928 bytes read in 1245 ms (2.6 MiB/s)
20378 bytes read in 265 ms (74.2 KiB/s)
## Booting kernel from Legacy Image at 42000000 ...
   Image Name:   Linux-3.14.28-g1a4251b
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    3336864 Bytes = 3.2 MiB
   Load Address: 40008000
   Entry Point:  40008000
   Verifying Checksum ... OK
## Flattened Device Tree blob at 41000000
   Booting using the fdt blob at 0x41000000
   Loading Kernel Image ... OK
   Loading Device Tree to 4fb4b000, end 4fb52f99 ... OK

Starting kernel ...

U-Boot Environment

On the SPI flash U-boot has both the U-boot application and the U-boot environment. Our default build has 8KB of environment which can be used for variables and scripts to control booting your operating system. These commands are relevant to manipulating the environment:

# Print all environment variables
env print -a

# Sets the variable bootdelay to 5 seconds
env set bootdelay 5;

# Variables can also contain commands
env set hellocmd 'led red on; echo Hello world; led green on;'

# Execute commands saved in a variable
env run hellocmd;

# Commit env changes to the spi flash
# Otherwise changes are lost
env save

# Restore env to default
env default -a

# Remove a variable
env delete emmcboot

For a production environment the best option for setting depends on the number of units. For a smaller number of units it may be simplest to update any required commands manually. For example, a custom cmdline option like "debug":

env set cmdline_append rw rootwait console=ttyAMA0,115200 loglevel=3 debug
env save

U-Boot Commands

These commands are agnostic to the operating system that is running, but may be useful for testing or scripting:

# The most important command is 
help
# This can also be used to see more information on a specific command
help mmc

# Boots into the binary at $loadaddr.  This file needs to have
# the uboot header from mkimage.  A uImage already contains this.
bootm
# Boots into the binary at $loadaddr, skips the initrd, specifies
# the fdtaddr so Linux knows where to find the board support
bootm ${loadaddr} - ${fdtaddr}

# Get a DHCP address
dhcp
# This sets ${ipaddr}, ${dnsip}, ${gatewayip}, ${netmask}
# and ${ip_dyn} which can be used to check if the dhcp was successful

# These commands are mainly used for scripting:
false # do nothing, unsuccessfully
true # do nothing, successfully

# Control LEDs
led red on
led green on
led all off
led red toggle

# This command is used to copy a file from most devices
# Load kernel from SD
load mmc 0:2 ${loadaddr} /boot/uImage
# Load kernel from USB
usb start
load usb 0:1 ${loadaddr} /boot/uImage

# View the fdt from u-boot with fdt
load mmc 0:2 ${fdtaddr} /boot/imx28-ts7680.dtb
fdt addr ${fdtaddr}
fdt print

# Blindly jump into any memory location
# This is similar to bootm, but it does not use the 
# u-boot header
load mmc 0:2 ${loadaddr} /boot/custombinary
go ${loadaddr}

# Browse fat,ext2,ext3,or ext4 filesystems:
ls mmc 0:2 /

# Similar to devmem in Linux, read/write arbitrary memory
# using mw and md
# write
mw 0x10000000 0xc0ffee00 1
# read
md 0x10000000 1

# Test memory.  Typically just used in production
mtest

# Read newly inserted SD card
mmc rescan
# Read SD card size
mmc dev 0
mmcinfo

# The NFS command is similar to 'load', but used over the network
dhcp
env set serverip 192.168.0.11
nfs ${loadaddr} 192.168.0.11:/path/to/somefile

# Test ICMP
dhcp
ping 192.168.0.11

# Reboot
reset

# SPI access is through the SF command
# Be careful with sf commands since
# this is where u-boot and the FPGA bitstream exist
# Improper use can render the board unbootable
sf probe

# Delay in seconds
sleep 10

# It is possible to load HUSH scripts that have been created with mkimage
load mmc 0:2 ${loadaddr} /boot/ubootscript
source ${loadaddr}

# Most commands have return values that can be used to test
# success, and HUSH scripting supports comparisons similar to
# test in Bash, but much more minimal
if load mmc 0:2 ${fdtaddr} /boot/uImage;
	then echo Loaded Kernel
else
	echo Could not find kernel
fi

# Commands can be timed with "time" similar to Linux
time sf probe

# Print U-boot version/build information
version

Modify Linux Kernel cmdline

The Linux kernel cmdline can be customized by modifying the cmdline_append variable. Keeping the default options here is recommended, but additional arguments can be appended to this variable.

env set cmdline_append rw rootwait console=ttyAMA0,115200 loglevel=3
env save

You can also change the kernel command line from the onboard Linux. From the board's shell prompt run:

apt-get update && apt-get install u-boot-tools -y
echo "env set cmdline_append rw rootwait console=ttyAMA0,115200 quiet" > /boot/boot.scr
mkimage -A arm -T script -C none -n 'tsimx28 boot script' -d /boot/boot.scr /boot/boot.ub

The boot.scr includes the plaintext commands to be run in u-boot on startup, and mkimage adds a checksum and header to this file which can be loaded by u-boot. The ub file should not be manually modified.

Linux NFS Boot

U-boot includes support for NFS which can be used to load your kernel, device tree binary, and root filesystem. Our default environment contains the nfsboot command which can be updated to boot NFS on your network:

# Set this to your NFS server ip
env set nfsip 192.168.0.11;

# Set this to your NFS root path.  The server root should be accessible at this path.
env set nfsroot /nfsroot/rootfs/
env save

To boot your NFS root:

# Boot to NFS once
run nfsboot;

# To make the NFS boot the persistent default
env set bootcmd run nfsboot;
env save

Linux USB Boot

By default, U-Boot will attempt to read a U-Boot script from a USB drive when the U-Boot jumper is set. It copies /tsinit.ub into memory and jumps in to the script. To make a bootable drive, create a single ext3 partition on a USB drive and unpack the rootfs tarball located here

The one addition is to create the tsinit.ub file in the root of the USB drive. In order to do this, a U-Boot script must be created and then converted to the .ub format. This process requires a set of U-Boot specific tools. These are available on most every linux distribution, the instructions below are for Debian, either run on a host PC or on the target. See the package installation documentation for other respective distributions.

Install U-Boot tools in Debian

apt-get update && apt-get install u-boot-tools -y

Create the file tsinit.scr in the root of the USB drive with the linux filesystem:

# Prepare with:
# mkimage -A arm -T script -C none -n 'imx28 usb' -d tsinit.scr tsinit.ub

# DO NOT MANUALLY EDIT THE .UB FILE

if load usb 0:1 ${loadaddr} /boot/ts${model}-fpga.vme;
        then fpga load 0 ${loadaddr} ${filesize};
fi;

load usb 0:1 ${fdtaddr} /boot/imx28-ts${model}.dtb;

load usb 0:1 ${loadaddr} /boot/uImage;

setenv bootargs root=/dev/sda1 ${cmdline_append};
bootm ${loadaddr} - ${fdtaddr};

Then in the same directory generate the tsinit.ub file:

mkimage -A arm -T script -C none -n 'imx28 usb' -d tsinit.scr tsinit.ub

You may need to install u-boot-tools or the equivalent package for your distribution.

U-Boot Recovery

The development tool, TS-9468, can be used to recover the SBC. Set the flip switch in the "Up" position so it lights up red when powered on to boot from the SPI flash on the TS-9468; the TS-9468 may not ship with a switch, without the switch populated the TS-9468 will automatically boot to the SPI flash on the TS-9468. Use the instructions in Update U-Boot to download and copy in the latest U-Boot binary to SD and boot the unit. And instead of the command listed, use the following:

env set spi onboard
run update-uboot

The script output will include a message saying that it is writing to the onboard SPI flash. The environment variable "spi" can be set to "offboard" in order to force writing to the TS-9468 in order to update the binary on there. Note that if the variable is not set, the script will write to the SPI flash of the SBC or TS-9468 based on the switch position (if there is one).

Update U-Boot

WARNING:

Installing your own u-boot is not recommended and may cause the board to fail to boot.

The latest U-Boot binary can be downloaded from the TS-7553-V2 FTP site. Copy this file to /boot/u-boot.sb on the 2nd partition of the SD card. The SPI flash can be updated by inserting that SD card in to the TS-7553-V2, setting the U-Boot and SD card jumpers, and powering up the unit. At the U-Boot prompt, the following command can be used:

run update-uboot

The above script will use the /boot/u-boot.sb file from the SD card or eMMC, depending on the state of the SD Boot jumper.

U-boot Development

We do provide our u-boot sources, but we do not recommend rebuilding a custom uboot if it can be avoided. If you still want to proceed with building a custom u-boot, use the master branch from the github here: https://github.com/embeddedarm/u-boot

Set the PATH variable to include the cross compiler used for the TS-7553-V2. The U-Boot binary can be built with the following:

./build-mx28 ts7553

This will output a u-boot.sb file you can use to write the SPI flash as listed in the Update U-Boot section

Debian Configuration

For development, it is recommended to work directly in Debian on the SD card. Debian provides many more packages and a much more familiar environment for users already versed in Debian. Through Debian it is possible to configure the network, use the 'apt-get' suite to manage packages, and perform other configuration tasks. Out of the box the Debian distribution does not have any default username/password set. The account "root" is set up with no password configured. It is possible to log in via the serial console without a password but many services such as ssh will require a password set or will not allow root login at all. It is advised to set a root password and create a user account when the unit is first booted.

Note:

Setting up a password for root is only feasible on the uSD image.

It is also possible to cross compile applications. Using a Debian host system will allow for installing a cross compiler to build applications. The advantage of using a Debian host system comes from compiling against libraries. Debian cross platform support allows one to install the necessary development libraries on the host, building the application on the host, and simply installing the runtime libraries on the target device. The library versions will be the same and completely compatible with each other. See the respective Debian cross compiling section for more information.

Configuring the Network

From almost any Linux system you can use 'ip' command or the 'ifconfig' and 'route' commands to initially set up the network.

# Bring up the CPU network interface
ifconfig eth0 up

# Or if you're on a baseboard with a second ethernet port, you can use that as:
ifconfig eth1 up

# Set an ip address (assumes 255.255.255.0 subnet mask)
ifconfig eth0 192.168.0.50

# Set a specific subnet
ifconfig eth0 192.168.0.50 netmask 255.255.0.0

# Configure your route.  This is the server that provides your internet connection.
route add default gw 192.168.0.1

# Edit /etc/resolv.conf for your DNS server
echo "nameserver 192.168.0.1" > /etc/resolv.conf

Most networks will offer a DHCP server, an IP address can be obtained from a server with a single command in linux:

Configure DHCP in Debian:

# To setup the default CPU ethernet port
dhclient eth0
# Or if you're on a baseboard with a second ethernet port, you can use that as:
dhclient eth1
# You can configure all ethernet ports for a dhcp response with
dhclient

Systemd provides a networking configuration option to allow for automatic configuration on startup. Systemd-networkd has a number of different configuration files, some of the default examples and setup steps are outlined below.

/etc/systemd/network/eth.network

[Match]
Name=eth*

[Network]
DHCP=yes

To use DHCP to configure DNS via systemd, start and enable the network name resolver service, systemd-resolved:

systemctl start systemd-resolved.service 
systemctl enable systemd-resolved.service
ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf

For a static config create a network configuration for that specific interface.

/etc/systemd/network/eth0.network

[Match]
Name=eth0

[Network]
Address=192.168.0.50/24
Gateway=192.168.0.1
DNS=192.168.0.1

For more information on networking, see Debian and systemd's documentation:

• Systemd Networking Documentation
• Debian Documentation

WIFI Client

If connecting to a WPA/WPA2 network, a wpa_supplicant config file must first be created:

wpa_passphrase yournetwork yournetworkpassphrase > /etc/wpa_supplicant/wpa_supplicant-wlan0.conf

Create the file /lib/systemd/system/wpa_supplicant@.service with these contents

[Unit]
Description=WPA supplicant daemon (interface-specific version)
Requires=sys-subsystem-net-devices-%i.device
After=sys-subsystem-net-devices-%i.device

[Service]
Type=simple
ExecStart=/sbin/wpa_supplicant -c/etc/wpa_supplicant/wpa_supplicant-%I.conf -i%I

[Install]
Alias=multi-user.target.wants/wpa_supplicant@%i.service

Create the file /etc/systemd/network/wlan0.network with:

[Match]
Name=wlan0

[Network]
DHCP=yes

See the systemctl-networkd example for setting a static IP for a network interface. The wlan0.network can be configured the same way as an eth.network.

To enable all of the changes that have been made, run the following commands:

systemctl enable wpa_supplicant@wlan0
systemctl start wpa_supplicant@wlan0
systemctl restart systemd-networkd

Host a WIFI Access Point

First, hostapd needs to be installed in order to manage the access point on the device:

apt-get update && apt-get install hostapd -y

Note:

The install process will start an unconfigured hostapd process. This process must be killed and restarted before a new hostapd.conf will take effect.

Edit /etc/hostapd/hostapd.conf to include the following lines:

interface=wlan0
driver=nl80211
ssid=YourAPName
channel=1

Note:

Refer to the kernel's hostapd documentation for more wireless configuration options.

To start the access point launch hostapd:

hostapd /etc/hostapd/hostapd.conf &

This will start up an access point that can be detected by WIFI clients. A DHCP server will likely be desired to assign IP addresses. Refer to Debian's documentation for more details on DHCP configuration.

Installing New Software

Debian provides the apt-get system which allows management of pre-built applications. The apt tools require a network connection to the internet in order to automatically download and install new software. The update command will download a list of the current versions of pre-built packages.

Older Debian releases are moved to a different server to indicate it is no longer getting security updates. To download packages for these older distributions, edit /etc/apt/sources.list to only have the following lines:

Jessie:

deb http://archive.debian.org/debian/ jessie main
deb-src http://archive.debian.org/debian/ jessie main

Wheezy:

deb http://archive.debian.org/debian/ wheezy main
deb-src http://archive.debian.org/debian/ wheezy main

After modifying that file, be sure to update the package list:

apt-get update

A common example is installing Java runtime support for a system. Find the package name first with search, and then install it.

root@ts:~# apt-cache search openjdk
jvm-7-avian-jre - lightweight virtual machine using the OpenJDK class library
freemind - Java Program for creating and viewing Mindmaps
icedtea-7-plugin - web browser plugin based on OpenJDK and IcedTea to execute Java applets
default-jdk - Standard Java or Java compatible Development Kit
default-jdk-doc - Standard Java or Java compatible Development Kit (documentation)
default-jre - Standard Java or Java compatible Runtime
default-jre-headless - Standard Java or Java compatible Runtime (headless)
jtreg - Regression Test Harness for the OpenJDK platform
libreoffice - office productivity suite (metapackage)
icedtea-7-jre-jamvm - Alternative JVM for OpenJDK, using JamVM
openjdk-7-dbg - Java runtime based on OpenJDK (debugging symbols)
openjdk-7-demo - Java runtime based on OpenJDK (demos and examples)
openjdk-7-doc - OpenJDK Development Kit (JDK) documentation
openjdk-7-jdk - OpenJDK Development Kit (JDK)
openjdk-7-jre - OpenJDK Java runtime, using Hotspot Zero
openjdk-7-jre-headless - OpenJDK Java runtime, using Hotspot Zero (headless)
openjdk-7-jre-lib - OpenJDK Java runtime (architecture independent libraries)
openjdk-7-source - OpenJDK Development Kit (JDK) source files
uwsgi-app-integration-plugins - plugins for integration of uWSGI and application
uwsgi-plugin-jvm-openjdk-7 - Java plugin for uWSGI (OpenJDK 7)
uwsgi-plugin-jwsgi-openjdk-7 - JWSGI plugin for uWSGI (OpenJDK 7)
                                                       

In this case you will want the openjdk-7-jre package. Names of packages are on Debian's wiki or the packages site.

With the package name apt-get install can be used to install the prebuilt packages.

apt-get install openjdk-7-jre
# More than one package can be installed at a time.
apt-get install openjdk-7-jre nano vim mplayer

For more information on using apt-get refer to Debian's documentation here.

Setting up SSH

To install ssh, install the package as normal with apt-get:

apt-get install openssh-server

Make sure the device is configured on the network and set a password for the remote user. SSH will not allow remote connections without a password or a valid SSH key pair.

passwd root

Note:

The default OpenSSH server will not permit root to login via SSH as a security precaution. To allow root to log in via ssh anyway, edit the /etc/ssh/sshd_config file and add the line PermitRootLogin yes in the authentication section. This change will take effect after reboot or after sshd service restart.

After this setup it is now possible to connect from a remote PC supporting SSH. On Linux/OS X this is the "ssh" command, or from Windows using a client such as PuTTY.

Note:

If a DNS server is not present on the target network, it is possible to save time at login by adding "UseDNS no" in /etc/ssh/sshd_config.

Starting Automatically

A systemd service can be created to start up headless applications. Create a file in /etc/systemd/system/yourapp.service

[Unit]
Description=Run an application on startup

[Service]
Type=simple
ExecStart=/usr/local/bin/your_app_or_script

[Install]
WantedBy=multi-user.target

If networking is a dependency add "After=network.target" in the Unit section. Once you have this file in place add it to startup with:

# Start the app on startup, but will not start it now
systemctl enable yourapp.service

# Start the app now, but doesn't change auto startup
systemctl start yourapp.service

Note:

See the systemd documentation for in depth documentation on services.

To start an application on bootup with X11 instead change the x-session-manager. By default the system starts xfce:

root@ts:~# ls -lah /usr/bin/x-session-manager 
lrwxrwxrwx 1 root root 35 May 26  2015 /usr/bin/x-session-manager -> /etc/alternatives/x-session-manager
root@ts:~# ls -lah /etc/alternatives/x-session-manager
lrwxrwxrwx 1 root root 19 May 26  2015 /etc/alternatives/x-session-manager -> /usr/bin/startxfce4

The x-session can be modified to only start specified processes. Create the file /usr/bin/mini-x-session with these contents:

#!/bin/bash
matchbox-window-manager -use_titlebar no &

exec xfce4-terminal

You may need to "apt-get install matchbox-window-manager." first. This is a tiny window manager which also has a few flags that simplify embedded use. Now enable this session manager and restart slim to restart x11 and show it now.

chmod a+x /usr/bin/mini-x-session
rm /etc/alternatives/x-session-manager
ln -s /usr/bin/mini-x-session /etc/alternatives/x-session-manager
service slim restart

If the x-session-manager process ever closes x11 will restart. The exec command allows a new process to take over the existing PID. In the above example xfce4-terminal takes over the PID of x-session-manager. If the terminal is closed with commands like exit the slim/x11 processes will restart.

Backup / Restore

If you are using a Windows workstation there is no support for writing directly to block devices. However, as long as one of your booting methods still can boot a kernel and the initrd you can rewrite everything by using a usb drive. This is also a good way to blast many stock boards when moving your product into production. You can find more information about this method with an example script here.

Note:

Note that the MBR installed by default on this board contains a 446 byte bootloader program that loads the initial power-on kernel and initrd from the first and second partitions. Replacing it with an MBR found on a PC would not work as a PC MBR contains an x86 code bootup program.

MicroSD Card

Click to download the latest tarball.

Most SD cards ship with a single partition, which is ideal. However the instructions below will destroy the partition table and use 'parted' to recreate it and make a single partition. Note that any other preferred tool can be used instead, however the partition table must be "MBR" format for U-Boot to properly parse it.

Using other OSs

At this time, we're unable to provide assistance with writing SD cards for our products from non-Linux based operating systems. We acknowledge however, that there are methods to write images and files from a variety of difference operating systems. If a native installation of Linux is unavailable, we recommend using a Virtual Machine. See the Getting Started section for links to common virtualization software and Linux installation.

Using a Linux workstation

An SD card can be written to allow it to be bootable. Download the above file and write this from a Linux workstation using the information below. A USB SD adapter can be used to access the card; or if the workstation supports direct connection of SD cards, that can be used instead. Once inserted in to the workstation, it is necessary to discover which /dev/ device corresponds with the inserted SD card before the image can be written.

Option 1: using 'lsblk'

---

Newer distributions include a utility called 'lsblk' which allows simple identification of the intended card.

Note:

This command may need to be run as the root user:

$ lsblk

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sdY      8:0    0   400G  0 disk 
├─sdY1   8:1    0   398G  0 part /
├─sdY2   8:2    0     1K  0 part 
└─sdY5   8:5    0     2G  0 part [SWAP]
sr0     11:0    1  1024M  0 rom  
sdX      8:32   1   3.9G  0 disk 
├─sdX1   8:33   1   7.9M  0 part 
├─sdX2   8:34   1     2M  0 part 
├─sdX3   8:35   1     2M  0 part 
└─sdX4   8:36   1   3.8G  0 part

In this case the, SD card is 4GB, so sdX is the target device and already contains 4 partitions. Note that sdX is not a real device, it could be sda, sdb, mmcblk0, etc. Technologic Systems is not responsible for any damages cause by using the improper device node for imaging an SD card. The instructions below to write to the device will destroy the partition table and any existing data!

Option 2: Using 'dmesg'

---

After plugging in the device, the 'dmesg' command can be used to list recent kernel events. When inserting a USB adapter, the last few lines of 'dmesg' output will be similar to the following (note that this command may need to be run as the root user):

$ dmesg
...
scsi 54:0:0:0: Direct-Access     Generic  Storage Device   0.00 PQ: 0 ANSI: 2
sd 54:0:0:0: Attached scsi generic sg2 type 0
sd 54:0:0:0: [sdX] 3862528 512-byte logical blocks: (3.97 GB/3.84 GiB)
...

In this case, sdX is shown as a 3.97GB card with a single partition. Note that sdX is not a real device, it could be sda, sdb, mmcblk0, etc. Technologic Systems is not responsible for any damages cause by using the improper device node for imaging an SD card. The instructions below to write to the device will destroy the partition table and any existing data!

The instructions below use the latest stock image, but it is also possible to use this process to update the TS-7553-V2 to the Linux 4.9 kernel with Debian Stretch image.

The following commands will reformat the first partition of the SD card, and unpack the latest filesystem on there. Replace the "/dev/sdX" on the first line with the correct whole disk device node!

# Update this variable to match the specific device node as it appears on your PC!
export SD_DEV="/dev/sdX"

# Verify nothing else has this mounted
sudo umount "${SD_DEV}"1

# Remove, and re-set the partition table, ensuring there is a single partition. Additional partitions can be added, however U-Boot expects the 1st partition to have the root filesystem tarball.
sudo dd if=/dev/zero bs=512 count=1 of="${SD_DEV}"
sudo parted -s -a optimal "${SD_DEV}" mklabel msdos
sudo parted -s -a optimal "${SD_DEV}" mkpart primary ext3 0% 100%
sudo mkfs.ext3 -F "${SD_DEV}"1

# Mount, unpack filesystem tarball, and flush all cached data
sudo mkfs.ext3 "${SD_DEV}"1
sudo mkdir /mnt/sd
sudo mount "${SD_DEV}"1 /mnt/sd/
wget https://files.embeddedTS.com/ts-arm-sbc/ts-7553-V2-linux/distributions/ts7553-V2-latest.tar.bz2
sudo tar -xf ts7553-V2-latest.tar.bz2 -C /mnt/sd
sudo umount /mnt/sd
sync

Note:

The ext4 filesystem can be used instead of ext3, but it may require additional options. U-Boot does not support the 64bit addressing added as the default behavior in recent revisions of mkfs.ext4. If using e2fsprogs 1.43 or newer, the options "-O ^64bit,^metadata_csum" must be used with ext4 for proper compatibility. Older versions of e2fsprogs do not need these options passed nor are they needed for ext3.

Once written, the files on disk can be verified to ensure they are the same as the source files in the archive. Reinsert the disk to flush the block cache completely, then run the following commands (Note that this expects to have the bash variable still set up from above):

sudo mount "${SD_DEV}"1 /mnt/sd
cd /mnt/sd/
sudo md5sum --quiet -c md5sums.txt
cd -
sudo umount /mnt/sd
sync

The md5sum command will report what differences there are, if any, and return if it passed or failed.

eMMC

These commands assume you are booted to the SD card:

# Verify nothing else has this mounted
umount /dev/mmcblk2p2

mkfs.ext4 /dev/mmcblk2p2
mkdir /mnt/emmc
mount /dev/mmcblk2p2 /mnt/emmc
wget ftp://ftp.embeddedarm.com/ts-arm-sbc/ts-7553-V2-linux/distributions/ts7553-V2-latest.tar.bz2
tar -xf ts7553-V2-latest.tar.bz2 -C /mnt/emmc
umount /mnt/emmc
sync

Software Development

Most of our examples are going to be in C, but Debian will include support for many more programming languages. Including (but not limited to) C++, PERL, PHP, SH, Java, BASIC, TCL, and Python. Most of the functionality from our software examples can be done from using system calls to run our userspace utilities. For higher performance, you will need to either use C/C++ or find functionally equivalent ways to perform the same actions as our examples. Our userspace applications are all designed to go through a TCP interface. By looking at the source for these applications, you can learn our protocol for communicating with the hardware interfaces in any language.

The most common method of development is directly on the SBC. Since debian has space available on the SD card, we include the build-essentials package which comes with everything you need to do C/C++ development on the board.

Editors

Vim is a very common editor to use in Linux. While it isn't the most intuitive at a first glance, you can run 'vimtutor' to get a ~30 minute instruction on how to use this editor. Once you get past the initial learning curve it can make you very productive. You can find the vim documentation here.

Emacs is another very common editor. Similar to vim, it is difficult to learn but rewarding in productivity. You can find documentation on emacs here.

Nano while not as commonly used for development is the easiest. It doesn't have as many features to assist in code development, but is much simpler to begin using right away. If you've used 'edit' on Windows/DOS, this will be very familiar. You can find nano documentation here.

Compilers

We only recommend the gnu compiler collection. There are many other commercial compilers which can also be used, but will not be supported by us. You can install gcc on most boards in Debian by simply running 'apt-get update && apt-get install build-essential'. This will include everything needed for standard development in c/c++.

You can find the gcc documentation here. You can find a simple hello world tutorial for c++ with gcc here.

Build tools

When developing your application typing out the compiler commands with all of your arguments would take forever. The most common way to handle these build systems is using a make file. This lets you define your project sources, libraries, linking, and desired targets. You can read more about makefiles here.

If you are building an application intended to be more portable than on this one system, you can also look into the automake tools which are intended to help make that easier. You can find an introduction to the autotools here.

Cmake is another alternative which generates a makefile. This is generally simpler than using automake, but is not as mature as the automake tools. You can find a tutorial here.

Debuggers

Linux has a few tools which are very helpful for debugging code. The first of which is gdb (part of the gnu compiler collection). This lets you run your code with breakpoints, get backgraces, step forward or backward, and pick apart memory while your application executes. You can find documentation on gdb here.

Strace will allow you to watch how your application interacts with the running kernel which can be useful for diagnostics. You can find the manual page here.

Ltrace will do the same thing with any generic library. You can find the manual page here.

Cross Compiling

While it is recommend to develop entirely on the SBC itself, it is also possible to develop from an x86 compatible Linux system using a cross compiler. For this SBC use the cross compiler located here. The resulting binary will be for ARM.

[user@localhost]$ /path/to/arm-fsl-linux-gnueabi/bin/arm-linux-gcc hello.c -o hello
[user@localhost]$ file hello
hello: ELF 32-bit LSB executable, ARM, version 1 (SYSV), dynamically linked (uses shared libs), not stripped

This is one of the simplest examples. For working with a larger project a Makefile will typically be used. More information about Makefiles is available here. Another common requirement is linking to third party libraries provided by Debian on the SBC. There is no exact set of steps for every project when cross compiling, but the process will be very much the same. Provide the cross compiler with access to the necessary headers, libraries, and source files, and install the binary on the target. The following example will link to sqlite from Debian.

Install the sqlite library and header on the SBC:

apt-get update && apt-get install -y libsqlite3-0 libsqlite-dev

This will fetch the binaries from the internet and install them on the SBC. The installed files can then be listed with dpkg:

dpkg -L libsqlite3-0 libsqlite3-dev

The needed files from this output will be the .h and .so files, they will need to be copied to the project directory on the cross-compling host.

See the example with libsqlite3 below. This is not intended to provide any functionality, but just call functions provided by sqlite.

#include <stdio.h>
#include <stdlib.h>
#include "sqlite3.h"

int main(int argc, char **argv)
{
	sqlite3 *db;
	char *zErrMsg = 0;
	int rc;
	printf("opening test.db\n");
	rc = sqlite3_open("test.db", &db);
	if(rc){
		fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db));
		sqlite3_close(db);
		exit(1);
	}
	if(rc!=SQLITE_OK){
		fprintf(stderr, "SQL error: %s\n", zErrMsg);
	}
	printf("closing test.db\n");
	sqlite3_close(db);
	return 0;
}

To build this with the external libraries the makefile below can be used. This will have to be adjusted for the proper toolchain path. In this example, the headers are located in external/include and the library in external/lib.

CC=/opt/arm-2008q3/bin/arm-none-linux-gnueabi-gcc
CFLAGS=-c -Wall

all: sqlitetest

sqlitetest: sqlitetest.o
        $(CC) sqlitetest.o external/lib/libsqlite3.so.0 -o sqlitetest
sqlitetest.o: sqlitetest.c
        $(CC) $(CFLAGS) sqlitetest.c -Iexternal/include/

clean:  
        rm -rf *o sqlitetest.o sqlitetest

The resulting binary can be copied to the target and executed. There are many ways to transfer the compiled binaries to the board. Using a network filesystem such as sshfs or NFS will be the simplest to use if needed frequently during development, but will require a setup. See the host linux distribution's manual for more details. The simplest network method is using ssh/sftp. If running Windows, winscp can be used, or just scp in linux. Make sure a password is set for a user account, root or otherwise, in order to properly ssh or scp files to the target. From winscp, enter the ip address of the SBC, the root username, and the password; this will create an explorer window that can use drag-and-drop of files to copy them to the target.

For scp in linux, run:

#replace with the binary name and the SBC IP address
scp sqlitetest root@192.168.0.50:/root/

After transferring the file to the board, execute it:

ts:~# ./sqlitetest 
opening test.db
closing test.db

Compile the Kernel

For adding new support to the kernel, or recompiling with more specific options you will need to have an x86 compatible Linux host available that can handle the cross compiling. Compiling the kernel on the board is not supported or recommended. Before building the kernel you will need to install a few support libraries on your workstation:

Prerequisites

All systems:

Download and unpack the cross compiler:

Note:

The cross compiler set up in the Cross Compiling section is 64-bit and can be used instead of the 32-bit cross compiler below. If using the aforementioned compiler, it is not necessary to install the 32-bit compatibility libraries as is it for the 32-bit cross compiler on a 64-bit Debian Jessie installation.

wget ftp://ftp.embeddedTS.com/ts-arm-sbc/ts-7680-linux/cross-toolchains/imx28-cross-glibc.tar.bz2
tar xvf imx28-cross-glibc.tar.bz2 -C /path/to/folder/

/path/to/folder can be any directory so long as the current user has permissions to write to it. Remember this path as its used later during the kernel build procedure.

RHEL/Fedora/CentOS:

yum install ncurses-devel ncurses
yum groupinstall "Development Tools" "Development Libraries"

Ubuntu/Debian:

sudo apt-get install build-essential libncurses5-dev libncursesw5-dev git u-boot-tools

If you are on a 64-bit system, then 32-bit libraries will be required for the toolchain, for newer Debian and Ubuntu distrubutions with Multiarch support, use the command:

sudo dpkg --add-architecture i386
sudo apt-get update
sudo apt-get install libc6-dev:i386 zlib1g-dev:i386

On older distributions:

sudo apt-get install ia32-libs

For other distributions, please refer to their documentation to find equivalent tools.

Download sources and configure

git clone https://github.com/embeddedTS/linux-3.14.28-imx28.git
cd linux-3.14.28-imx28/

# These next commands set up some necessary environment variables
export ARCH=arm
export CROSS_COMPILE=/path/to/folder/arm-fsl-linux-gnueabi/bin/arm-linux-
# If using the 64-bit cross compiler from the Cross Compiling section, the following CROSS_COMPILE variable can be
# used if the environment PATH is set up properly:
# export CROSS_COMPILE=arm-linux-gnueabi-
export LOADADDR=0x40008000

# This sets up the default configuration that we ship with
make ts76xx_defconfig

Once you have the configuration ready you can make your changes to the kernel. Commonly a reason for recompiling is to add support that was not built into the standard image's kernel. You can get a menu to browse available options by running:

make menuconfig

You can use the "/" key to search for specific terms through the kernel.

Build the kernel

Once you have it configured you can begin building the kernel. This usually takes about 5-10 minutes. This group of commands will also output a uImage file used by U-Boot on the TS-7680.

make && make uImage && make modules

We recommend running 'make' with the -jX argument, where X is the number of CPU cores+1 present on the build machine. This will greatly increase build speed.

Install the kernel/initramfs, headers, and modules

Next you need to install the kernel and modules to the SD card. We provide a simple script to copy the kernel uImage file, kernel modules, and headers to the SD card to update everything at once.

For example, if your workstation's SD card is /dev/mmcblk0:

./install_hdr_mod mmcblk0p2

If your workstation's SD card is /dev/sdc:

./install_hdr_mod sdc2

Features

Battery Backed RTC

The TS-7553-V2 implements a M41T00S STMicro Battery Backed RTC using an external and replaceable coin cell battery. This RTC is connected to the CPU via I2C and is handled by the kernel and is presented as a standard RTC device in linux.

CAN

The i.MX28 CPU has two FlexCAN ports that use the linux SocketCAN implementation. The ports can be set up and used with the following commands:

ip link set can0 up type can bitrate 1000000
ip link set can1 up type can bitrate 1000000

Note:

The CAN_EN# signal is connected to CPU DIO 126 and is active low. The pin is de-asserted until the TS systemd script runs and asserts the enable bit. See the DIO section for more information.

At this point the ports can be used with standard SocketCAN libraries. In debian we provide cansend and candump to test the ports or as a simple packet send/recv tool. In order to test the two ports together, tie CAN_H of both CAN ports together, and do the same for CAN_L. Then use the following commands:

candump can0 &
cansend can1 7Df#03010c
#This command will return
  can0  7DF  [3] 03010c

The above example packet is designed to work with the Ozen Elektronik myOByDic 1610 ECU simulator to read the RPM speed. In this case, the ECU simulator would return data from candump with:

 <0x7e8> [8] 04 41 0c 60 40 00 00 00 
 <0x7e9> [8] 04 41 0c 60 40 00 00 00 

In the output above, columns 6 and 7 are the current RPM value. This shows a simple way to prove out the communication before moving to another language.

The following example sends the same packet and parses the same response in C:

#include <stdio.h>
#include <pthread.h>
#include <net/if.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <assert.h>
#include <linux/can.h>
#include <linux/can/raw.h>

int main(void)
{
	int s;
	int nbytes;
	struct sockaddr_can addr;
	struct can_frame frame;
	struct ifreq ifr;
	struct iovec iov;
	struct msghdr msg;
	char ctrlmsg[CMSG_SPACE(sizeof(struct timeval)) + CMSG_SPACE(sizeof(__u32))];
	char *ifname = "can0";
 
	if((s = socket(PF_CAN, SOCK_RAW, CAN_RAW)) < 0) {
		perror("Error while opening socket");
		return -1;
	}
 
	strcpy(ifr.ifr_name, ifname);
	ioctl(s, SIOCGIFINDEX, &ifr);
	addr.can_family  = AF_CAN;
	addr.can_ifindex = ifr.ifr_ifindex;
 
	if(bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
		perror("socket");
		return -2;
	}
 
 	/* For the ozen myOByDic 1610 this requests the RPM guage */
	frame.can_id  = 0x7df;
	frame.can_dlc = 3;
	frame.data[0] = 3;
	frame.data[1] = 1;
	frame.data[2] = 0x0c;
 
	nbytes = write(s, &frame, sizeof(struct can_frame));
	if(nbytes < 0) {
		perror("write");
		return -3;
	}

	iov.iov_base = &frame;
	msg.msg_name = &addr;
	msg.msg_iov = &iov;
	msg.msg_iovlen = 1;
	msg.msg_control = &ctrlmsg;
	iov.iov_len = sizeof(frame);
	msg.msg_namelen = sizeof(struct sockaddr_can);
	msg.msg_controllen = sizeof(ctrlmsg);  
	msg.msg_flags = 0;

	do {
		nbytes = recvmsg(s, &msg, 0);
		if (nbytes < 0) {
			perror("read");
			return -4;
		}

		if (nbytes < (int)sizeof(struct can_frame)) {
			fprintf(stderr, "read: incomplete CAN frame\n");
		}
	} while(nbytes == 0);

	if(frame.data[0] == 0x4)
		printf("RPM at %d of 255\n", frame.data[3]);
 
	return 0;
}

See the Kernel's CAN documentation here. Other languages have bindings to access CAN such as Python, Java using JNI.

In production use of CAN we also recommend setting a restart-ms for each active CAN port.

ip link set can0 type can restart-ms 100

This allows the CAN bus to automatically recover in the event of a bus-off condition.

CPU

This board features the i.MX286 454 MHz ARM9 from NXP. For more information about the processor and it's included peripherals, refer to the CPU manual.

DIO

Note:

This section is incomplete

The TS-7553-V2 offers DIO, inputs, and low-side switches to accommodate nearly every application. The DIO exposed to various headers and terminals are controlled via the FPGA or CPU. All DIOs are controlled via the kernel sysfs interface. See the kernel's documentation here for more detail. The FPGA DIO pins all implement a crossbar switch and can be set to any combination of inputs and outputs. All DIO are 3.3 V tolerant unless otherwise noted. The low-side switches are able to sink 500 mA each with a maximum voltage input of 30 V (protected by a 30 V Zener diode). The low-side switches, when de-asserted, are high impedance inputs with a pullup resistor. A logical 0 input occurs from roughly 0 V to 1.5 V, while a logical 1 input occurs from roughly 1.6 V and higher on the low-side switches when in input mode.

To interact with DIO pins through the sysfs interface, it first must be exported to userspace, for example, DIO 237 is the BT_EN pin provided by the FPGA:

echo "237" > /sys/class/gpio/export

If you receive a permission denied on a pin that means it is claimed by another kernel driver. If it succeeds you will have a /sys/class/gpio/gpio237/ directory. The relevant files in this directory are:

 direction - "out" or "in"
 value - write "1" or "0", or read "1" or "0" if direction is in
 edge - write with "rising", "falling", or "none"

# Set GPIO 237 high
echo "out" > /sys/class/gpio/gpio237/direction
echo "1" > /sys/class/gpio/gpio237/value
# Set GPIO 237 low
echo "0" > /sys/class/gpio/gpio237/value

# Read the value of GPIO 237
echo "in" > /sys/class/gpio/gpio237/direction
cat /sys/class/gpio/gpio237/value

As an output, the value file can be written to 0 for low (GND), or 1 for high (3.3V). As an input the GPIO will have a 100k pullup. It is also possible to use any processor GPIO as an interrupt by writing the edge value, and then using select() or poll() on the value file for changes.

eMMC Interface

The i.MX28 SD card controller support the MMC specification. This SBC includes a soldered down eMMC IC to provide on-board flash media.

Our default software image contains 2 partitions:

Device	Contents
/dev/mmcblk2	eMMC block device
/dev/mmcblk2p1	Unused
/dev/mmcblk2p2	Full Debian linux partition

External Reset

Note:

Use caution when using the push switch as a hardware reset mechanism. Filesystem corruption can occur if proper precautions are not taken and a hardware reset occurs.

This SBC has a multi-purpose tactile button at a right angle to the PCB. This button can be used as a mechanism to issue a hardware reset to the SBC or as a way to wake up the device from its sleep modes (see Sleep for more information). Additionally, it can be set up as a generic input for user applications.

To enable or disable the hardware reset functionality:

tsmicroctl --resetswitchon  #Enable hardware reset
tsmicroctl --resetswitchoff #Disable hardware reset

To read the state of the input pin, see the DIO section for information on reading the Push Switch.

I2C

The i.MX28 CPU I2C pins are not exposed to any external interfaces on this SBC. Because of this, bitbanging is strongly recommended for any attached peripherals that would utilize I2C.

Technologic Systems recommends using direct bitbanging of I2C pins from userspace to drive an I2C interface. See the DIO section for further information on manipulating DIO pins.

Another option is to implement i2c-gpio in linux. This allows for an I2C physical interface on GPIO pins, but uses the kernel I2C software interface to read and write data on the I2C bus. See linux kernel documentation and i2c-dev for more information on this.

Jumpers

The TS-7553-V2 has a set of jumpers located near the SuperCaps on the read edge of the SBC. These jumpers control a number of aspects of the TS-7553-V2's behavior. The jumpers are labeled on the silkscreen rather than numbered:

Label	Description
No CHRG	When jumper is set, disable charging of the SuperCaps. Beneficial for early development and testing.
SD Boot	When jumper is set, boot kernel and Debian from the SD card. Otherwise boot kernel and Debian from eMMC.
U Boot	When jumper is set, pause booting in U-Boot and drop to a U-Boot shell. Otherwise booth straight to Debian.
CAN	When jumper is set, adds a 120 ohm termination resistor across CAN0 H and L pins. (Note: the CAN1 interface always has a 120 ohm termination)
485	When jumper is set, adds a 120 ohm termination resistor across RS-485 + and - pins.

LEDs

On all of our SBCs we include 2 indicator LEDs which are under software control. You can manipulate these using "tshwctl --greenledon --redledon" or "tshwctl --greenledoff --redledoff". The LEDs have 4 behaviors from default software.

Green Behavior	Red behavior	Meaning
Solid On	Off	System is booted and running
Solid On	On for approximately 20s, then off	The red LED will remain on from power on until Debian has finished booting. The first boot of the unit will have the LED on longer as part of this process is generating SSH keys for the unit.
On for 10s, off for 100ms, and repeating	On for 10s, off for 100ms, and repeating	The watchdog is continuously resetting the board. This happens when the system cannot find a valid boot device, or the watchdog is otherwise not being fed. This is normally fed by the kernel once a valid boot media has started. See the #Watchdog section for more details.
Off	Off	The SBC is not able to boot. Typically either the board is not being supplied with enough voltage, or the SBC has been otherwise damaged. If a stable voltage is being provided and the supply is capable of providing at least 1A to the SBC, an RMA is suggested.
Blinking about 5ms on, about 10ms off.	Blinking about 5ms on, about 10ms off.	The board is receiving too little power, or something is drawing too much current from the unit's power rails.

Linux GPIO LED control:

LED	DIO
Red#	7
Green#	5

MicroSD Card Interface

The i.MX6ul SD card controller is used for the SD card present on the board which supports the SD and SDHC specifications. This controller has been tested with Sandisk Extreme SD cards which allow read speeds up to 20.5MB/s, and write speeds up to 21.5MB/s.

Our default software image contains a single partition:

Device	Contents
/dev/mmcblk0	SD Card block device
/dev/mmcblk0p1	Full Debian linux partition

Reboot Source

The supervisory microcontroller is capable of saving and displaying the reason for the most recent reboot. This can be used to detect various errors that may occur in the field, as well as simple accounting of events. The source can be queried with tsmicroctl:

tsmicroctl -i

reboot_source=poweron

Possible sources and causes are:

Source	Possible causes
poweron	Power removed, Super Caps discharged, and then power applied
brownout	Like "poweron," however the SuperCaps have not fully discharged
WDT	WDT timeout; reboot command (which reboots via WDT)
resetswitch	The reset switch has been enabled and has been asserted
sleep	The system has woken up from a sleep command

Relay

The TS-7553-V2 has one SPDT relay rated for 5 A at 277 VAC or 30 VDC that can be toggled through a DIO pin. The PCH-105D2H relay closes in 10ms, and opens in 5ms. A very safe assumption would be that it will switch after 20ms. The common, NO (Normally Open), and NC (Normally Closed) connections are brought out on a pin header. See the DIO section of the manual for information on manipulating the relays.

Contact	Location
COM	CN8_2
NO	CN8_3
NC	CN8_1

Sleep

Note:

As soon as the sleep command is issued the unit will go to sleep. If the proper precautions are not taken, filesystem corruption can result as the sleep mode removes all power from the CPU and other peripherals on the SBC

The addition of a microcontroller on board this SBC allows it to play a supervisory role over the CPU.

Low power sleep mode will remove power from all of the rails, turning off the CPU and every other peripheral save for the microcontroller. This mode offers extreme power savings, only requiring around 90 mW of power, with the ability to wake up after an arbitrary timeout (up to 1847297s, which is 21d 9h 8m 17s) with a 1s resolution. In order to enter this mode, issue the following command:

tsmicroctl --sleep --timewkup <time in seconds> --resetswitchwkup

Waking up from a sleep will take roughly 4-5s from when the timer expires or when the reset button is pressed. This is normal bootup time for the CPU.

Note that both --timewkup and --resetswitchwkup are optional arguments, you can pass none, one, or both. If no arguments are passed then the SBC will remain in sleep mode forever, until power is removed completely and re-applied. This can be useful instead of halting in linux as sleeping would consume far less power than simply halting the CPU. Be aware however, that if the Super Caps are installed they will keep power to the on-board microcontroller for a very long time. If the Super Caps are used than an external wakeup via timer or reset switch is highly recommended.

SPI

This SBC utilizes all of the i.MX28 CPU SPI ports for the SD cards, therefore there is no externally available SPI peripheral from the CPU. Because of this, bitbanging is strongly recommended for any attached peripherals that would utilize SPI.

Technologic Systems recommends using direct bitbanging of SPI pins from userspace to drive an SPI interface. See the DIO section for further information on manipulating DIO pins.

Another option is to implement spi-gpio in linux. This allows for a SPI physical interface on GPIO pins, but uses the kernel SPI software interface to read and write data on the SPI bus. See linux kernel documentation, spi-gpio, and spidev for more information on this.

Temperature Sensor

Note:

Pending software example

UARTs

Note:

This section is incomplete at this time

The TS-7553-V2 CPU offers 5 UARTs. The table below lists the CPU UARTs with their pin locations.

Dev. Name	Type	TX / + Loc.	RX / - Loc.	RTS Loc.	CTS Loc.
ttyAPP0	RS-232	HD2_3	HD2_2	HD2_7	HD2_8
ttyAPP1	RS-232	J1_3	J1_2	N/A	N/A
ttyAPP2	RS-485	J1_1 / HD2_1	J1_6 / HD2_6	N/A	N/A
ttyAPP3	TTL	HD1_12	HD1_10	N/A	N/A
ttyAPP4	TTL	CN4_3 / P3_3	CN4_2 / P3_2	N/A	N/A

RS-485

The TS-7553-V2 offers one RS-485 port. The half-duplex transmit-enable is handled by the CPU PWM and a hardware circuit to enable TXEN based on this PWM value. The following command must be issued before RS-485 will operate at the specified frequency with TXEN.

tshwctl --autotxen --baud <baud>

Additionally, different modes can be passed to the command to adjust for the number of bits, for example:

tshwctl --autotxen --baud <baud> --mode 8n1  #Default 8n1 mode, 8 data bits, no parity, 1 stop bit
tshwctl --autotxen --baud <baud> --mode 7e2  #7 data bits, even parity, 2 stop bits

Note that the baud and mode actually used on the UART must match what is passed to tshwctl. Any differences will cause TXEN to be released too soon or held too long and cause unexpected issues on the bus. If the mode or baud rate of the UART is changed, the tshwctl commands must be re-issued with the new settings.

USB

The USB host port is a standard USB 2.0 at 480Mbps. The Linux kernel provides most of the USB support, and some devices may require a kernel recompile. For creating custom USB support, libusb may be the easiest route.

USB 5V Power can be disabled or re-enabled using DIO 69, marked EN_USB_5V on the schematic. See the syscon for more information on using this bit.

See the WIFI-N-USB manual for information on our WIFI support.

Watchdog

This SBC implements a Watch Dog Timer in a microcontroller on the SBC. An external WDT allows for high assurance operation of the WDT, as it uses external hardware, kernel level software, and userspace level software. If any of the three fail then the WDT will timeout and reboot the whole system. A standard kernel WDT driver is in place. As soon as the kernel starts it will start the WDT and feed it on 30 second timeouts every 15 seconds. If a userspace application opens and uses the watchdog file, the kernel will stop auto-feeding and the user application is now responsible for feeding the WDT. The kernel driver supports the "Magic Close" feature of the WDT. This means that a 'V' character must be fed in to the watchdog file before the file is closed in order to disable the WDT. Additionally, if the kernel is compiled with CONFIG_WATCHDOG_NOWAYOUT then the WDT can never be stopped once it is started at boot.

See the Linux WDT API documentation for more information.

External Interfaces

HD1 Pin Header

Pin Name HD1_1 VIN HD1_2 POE_78 HD1_3 GND HD1_4 POE_45 HD1_5 GND HD1_6 POE_TX HD1_7 DIO 41 HD1_8 POE_RX HD1_9 DIO 40 HD1_10 UART3_RXD HD1_11 USB OTG - HD1_12 UART3_TXD HD1_13 USB OTG + HD1_14 DIO 39 HD1_15 5 V HD1_16 5 V

Pin Layout 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

HD2 Pin Header

Pin Name HD2_1 RS-485 + HD2_2 UART0_RXD HD2_3 UART0_TXD HD2_4 CAN1_H HD2_5 GND HD2_6 RS-485 - HD2_7 UART0_RTS HD2_8 UART0_CTS HD2_9 CAN1_L HD2_10 NC

Pin Layout 1 6 2 7 3 8 4 9 5 10

HD4 Keypad Interface

Pin	Name
HD4_1	3.3 V
HD4_2	DIO 17
HD4_3	DIO 116
HD4_4	DIO 117
HD4_5	DIO 122
HD4_6	GND

HD5 (DIO 1)

Pin Name HD5_1 DIO 26 HD5_2 3.3 V HD5_3 DIO 27 HD5_4 DIO 48 HD5_5 DIO 51 HD5_6 DIO 28 HD5_7 DIO 52 HD5_8 DIO 16 HD5_9 DIO 49 HD5_10 GND

Pin Layout 1 2 3 4 5 6 7 8 9 10

CN4 XBee Socket

Pin Name CN4_1 3.3 V CN4_2 UART4_RXD CN4_3 UART4_TXD CN4_4 NC CN4_5 CPU_RESET# CN4_6 NC CN4_7 NC CN4_8 NC CN4_9 DIO 16 CN4_10 GND CN4_11 DIO 49 CN4_12 DIO 17 CN4_13 NC CN4_14 NC CN4_15 DIO 48 CN4_16 DIO 28 CN4_17 DIO 52 CN4_18 DIO 51 CN4_19 DIO 27 CN4_20 DIO 26

Pin Layout 1 20 2 19 3 18 4 17 5 16 6 15 7 14 8 13 9 12 10 11

Revisions and Changes

Software Images

TS-7553-V2 Image Changelog

Product Notes

FCC Advisory

This equipment generates, uses, and can radiate radio frequency energy and if not installed and used properly (that is, in strict accordance with the manufacturer's instructions), may cause interference to radio and television reception. It has been type tested and found to comply with the limits for a Class A digital device in accordance with the specifications in Part 15 of FCC Rules, which are designed to provide reasonable protection against such interference when operated in a commercial environment. Operation of this equipment in a residential area is likely to cause interference, in which case the owner will be required to correct the interference at his own expense.

If this equipment does cause interference, which can be determined by turning the unit on and off, the user is encouraged to try the following measures to correct the interference:

Reorient the receiving antenna. Relocate the unit with respect to the receiver. Plug the unit into a different outlet so that the unit and receiver are on different branch circuits. Ensure that mounting screws and connector attachment screws are tightly secured. Ensure that good quality, shielded, and grounded cables are used for all data communications. If necessary, the user should consult the dealer or an experienced radio/television technician for additional suggestions. The following booklets prepared by the Federal Communications Commission (FCC) may also prove helpful:

How to Identify and Resolve Radio-TV Interference Problems (Stock No. 004-000-000345-4) Interface Handbook (Stock No. 004-000-004505-7) These booklets may be purchased from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

Limited Warranty

See our Terms and Conditions for more details.

WARNING:

Writing ANY of the CPU's One-Time Programmable registers will immediately void ALL of our return policies and replacement warranties. This includes but is not limited to: the 45-day full money back evaluation period; any returns outside of the 45-day evaluation period; warranty returns within the 1 year warranty period that would require SBC replacement. Our 1 year limited warranty still applies, however it is at our discretion to decide if the SBC can be repaired, no warranty replacements will be provided if the OTP registers have been written.