TS-4100 Debian Sections
Debian Stretch(9)
Getting Started
The stock image uses a Debian Stretch distribution and Linux kernel version 4.9. The latest image can be downloaded below.
This image can then be written to a microSD card or the on-board eMMC flash in order to be booted on the TS-4100.
Debian Networking
| Note: | The first physical port on the TS-4100 (or on Baseboards with a single port) is given the name "eth1", while the second port is "eth0". |
By default, Debian Stretch does not configure or bring up any interfaces.
Debian can automatically set up the networking based on the contents of "/etc/network/interfaces.d/" files. For example, to enable DHCP for "eth0" by default on startup:
echo "auto eth0
iface eth0 inet dhcp" > /etc/network/interfaces.d/eth0
To set up a static IP:
echo "auto eth0
iface eth0 inet static
address 192.168.0.50
netmask 255.255.255.0
gateway 192.168.0.1" > /etc/network/interfaces.d/eth0
echo "nameserver 1.1.1.1" > /etc/resolv.conf
To make this take effect immediately for either option:
service networking restart
To configure other interfaces, replace "eth0" with the other network device name. Some interfaces may use predictable interface names. For example, the traditional name for an ethernet port might be "eth1", but some devices may use "enp1s0" for PCIe, or "enx00D069C0FFEE" (the MAC address appended) for USB ethernet interfaces. Run 'ifconfig -a' or 'ip a' to get a complete list of interfaces, including the ones that are not configured.
Debian Wi-Fi Client
| Note: | The latest image for this platform as of April 28th, 2022 has known issues with the Wi-Fi driver due to incompatibility with cfg80211 powersave modes.
If using Wi-Fi, it is strongly recommended to bring up the Wi-Fi interface, and then run This issue will be addressed in future images and has already been addressed in our kernel sources. We will continue to provide updates as we receive them from the Wi-Fi module manufacturer. |
Wireless interfaces are also managed with configuration files in "/etc/network/interfaces.d/". For example, to connect as a client to a WPA network with DHCP. Note some or all of this software may already be installed on the target SBC.
Install wpa_supplicant:
apt-get update && apt-get install wpasupplicant -y
Run:
wpa_passphrase youressid yourpassword
This command will output information similar to:
network={
ssid="youressid"
#psk="yourpassword"
psk=151790fab3bf3a1751a269618491b54984e192aa19319fc667397d45ec8dee5b
}
Use the hashed PSK in the specific network interfaces file for added security. Create the file:
/etc/network/interfaces.d/wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
wpa-ssid youressid
wpa-psk 151790fab3bf3a1751a269618491b54984e192aa19319fc667397d45ec8dee5bTo have this take effect immediately:
service networking restart
For more information on configuring Wi-Fi, see Debian's guide here.
Debian Wi-Fi Access Point
| Note: | The latest image for this platform as of April 28th, 2022 has known issues with the Wi-Fi driver due to incompatibility with cfg80211 powersave modes.
If using Wi-Fi, it is strongly recommended to bring up the Wi-Fi interface, and then run This issue will be addressed in future images and has already been addressed in our kernel sources. We will continue to provide updates as we receive them from the Wi-Fi module manufacturer. |
This section will discuss setting up the WiFi device as an access point that is bridged to an ethernet port. That is, clients can connect to the AP and will be connected to the ethernet network through this network bridge. The ethernet network must provide a DHCP server; this will be passed through the bridge to WiFi client devices as they connect.
It is also possible to run a DHCP client on the platform itself. In this case the hostapd.conf file needs to be set up without bridging and a DHCP server needs to be configured. Refer to Debian's documentation for more details on DHCP server configuration.
The 'hostapd' utility is used to manage the access point of the device. This is usually installed by default, but can be installed with:
apt-get update && apt-get install hostapd -y
| Note: | The install process may start an unconfigured 'hostapd' process. This process must be killed before moving forward. |
Modify the file "/etc/hostapd/hostapd.conf" to have the following lines:
ssid=YourWiFiName
wpa_passphrase=Somepassphrase
interface=wlan0
bridge=br0
auth_algs=3
channel=7
driver=nl80211
hw_mode=g
logger_stdout=-1
logger_stdout_level=2
max_num_sta=5
rsn_pairwise=CCMP
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP CCMP
| Note: | Refer to the kernel's hostapd documentation for more wireless configuration options. |
The access point can be started and tested by hand:
hostapd /etc/hostapd/hostapd.conf
Systemd auto-start with bridge to eth0
It is possible to configure the auto-start of 'hostapd' through systemd. The configuration outlined below will set up a bridge with "eth0", meaning the Wi-Fi connection is directly connected to the ethernet network. The ethernet network is required to have a DHCP server present and active on it to assign Wi-Fi clients an IP address. This setup will allow Wi-Fi clients access to the same network as the ethernet port, and the bridge interface will allow the platform itself to access the network.
Set up hostapd
First, create the file "/etc/systemd/system/hostapd_user.service" with the following contents:
[Unit]
Description=Hostapd IEEE 802.11 AP
Wants=network.target
Before=network.target
Before=network.service
After=sys-subsystem-net-devices-wlan0.device
After=sys-subsystem-net-devices-br0.device
BindsTo=sys-subsystem-net-devices-wlan0.device
BindsTo=sys-subsystem-net-devices-br0.device
[Service]
Type=forking
PIDFile=/run/hostapd.pid
ExecStart=/usr/sbin/hostapd /etc/hostapd/hostapd.conf -P /run/hostapd.pid -B
[Install]
WantedBy=multi-user.target
Then enable this in systemd:
systemctl enable hostapd_user.service
systemctl enable systemd-networkd
Set up bridging
Create the following files with the listed contents.
"/etc/systemd/network/br0.netdev"
[NetDev]
Name=br0
Kind=bridge
"/etc/systemd/network/br0.network"
[Match]
Name=br0
[Network]
DHCP=yes
"/etc/systemd/network/bridge.network"
[Match]
Name=eth0
[Network]
Bridge=br0
Debian Wi-Fi Concurrent Client / Access Point
| Note: | The latest image for this platform as of April 28th, 2022 has known issues with the Wi-Fi driver due to incompatibility with cfg80211 powersave modes.
If using Wi-Fi, it is strongly recommended to bring up the Wi-Fi interface, and then run This issue will be addressed in future images and has already been addressed in our kernel sources. We will continue to provide updates as we receive them from the Wi-Fi module manufacturer. |
The Wi-Fi device on this platform supports concurrent operation of client and access point (STA and AP). Please see the "Wi-Fi Client" section above first to connect the Wi-Fi module, in STA mode, to an external AP. This demo showcases the Wi-Fi module starting its own AP mode via hostapd with a simple static IP address while also being concurrently connected to a separate AP.
The 'hostapd' utility is used to manage the access point of the device. This is usually installed by default, but can be installed with:
apt-get update && apt-get install hostapd -y
| Note: | The install process may start an unconfigured 'hostapd' process. This process must be killed before moving forward. |
Modify the file /etc/hostapd/hostapd.conf to have the following lines:
ssid=YourWiFiName
wpa_passphrase=Somepassphrase
interface=p2p0
auth_algs=3
channel=<channel>
driver=nl80211
hw_mode=g
logger_stdout=-1
logger_stdout_level=2
max_num_sta=5
rsn_pairwise=CCMP
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP CCMP
| Note: | The channel used for AP must match the channel the STA is using! Be sure to set 'channel=...' in the above file to a proper channel number. |
| Note: | Refer to the kernel's hostapd documentation for more wireless configuration options. |
In order for the concurrent modes to work, a separate virtual wireless device must first be created. Note that hostapd.conf above lists interface=p2p0, a second interface with this name must be created:
iw wlan0 interface add p2p0 type managed
The access point can then be started and tested by hand:
hostapd /etc/hostapd/hostapd.conf &
An IP address can be set to p2p0:
ifconfig p2p0 192.168.0.1
From this point, other Wi-Fi clients can connect to the SSID YourWiFiName with the WPA2 key Somepassphrase with a static IP in the range of 192.168.0.0/24, and will be able to access the platform at 192.168.0.1. More advanced configurations are also possible, including bridging, routing/NAT, or simply separate networks with the Wi-Fi module connecting to a network and hosting its own private network with DHCP.
Debian Application Development
Debian Stretch Cross Compiling
Debian Stretch provides cross compilers from the Debian apt repository archive for Debian Stretch. An install on a workstation can build for the same release on other architectures. A Linux desktop or laptop PC, virtual machine, or chroot will need to be used for this. Debian Stretch for a workstation can be downloaded from here.
From a Debian workstation (not the target), run these commands to set up the cross compiler:
# Run "lsb_release -a" and verify Debian 9.X is returned. These instructions are not
# expected to work on any other version or distribution.
su root
# Not needed for the immediate apt-get install, but used
# so we can install package:armhf for cross compiling
dpkg --add-architecture armhf
apt-get update
apt-get install curl build-essential crossbuild-essential-armhf -y
This will install a toolchain that can be used with the prefix "arm-linux-gnueabihf-". The standard GCC tools will start with that name, eg "arm-linux-gnueabihf-gcc".
The toolchain can now compile a simple hello world application. Create hello-world.c on the Debian workstation:
#include <stdio.h>
int main(){
printf("Hello World\n");
}
To compile this:
arm-linux-gnueabihf-gcc hello-world.c -o hello-world
file hello-world
This will return that the binary created is for ARM. Copy this to the target platform to run it there.
Debian Stretch supports multiarch which can install packages designed for other architectures. On workstations this is how 32-bit and 64-bit support is provided. This can also be used to install armhf packages on an x86 based workstation.
This cross compile environment can link to a shared library from the Debian root. The package would be installed in Debian on the workstation to provide headers and libraries. This is included in most "-dev" packages. When run on the arm target it will also need a copy of the library installed, but it does not need the -dev package.
apt-get install libcurl4-openssl-dev:armhf
# Download the simple.c example from curl:
wget https://raw.githubusercontent.com/bagder/curl/master/docs/examples/simple.c
# After installing the supporting library, curl will link as compiling on the unit.
arm-linux-gnueabihf-gcc simple.c -o simple -lcurl
Copy the binary to the target platform and run on the target. This can be accomplished with network protocols like NFS, SCP, FTP, etc.
If any created binaries do not rely on hardware support like GPIO or CAN, they can be run using 'qemu'.
# using the hello world example from before:
./hello-world
# Returns Exec format error
apt-get install qemu-user-static
./hello-world
Debian 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.
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 default-jdk - Standard Java or Java compatible Development Kit default-jdk-doc - Standard Java or Java compatible Development Kit (documentation) default-jdk-headless - Standard Java or Java compatible Development Kit (headless) 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) openjdk-8-dbg - Java runtime based on OpenJDK (debugging symbols) openjdk-8-demo - Java runtime based on OpenJDK (demos and examples) openjdk-8-doc - OpenJDK Development Kit (JDK) documentation openjdk-8-jdk - OpenJDK Development Kit (JDK) openjdk-8-jdk-headless - OpenJDK Development Kit (JDK) (headless) openjdk-8-jre - OpenJDK Java runtime, using Hotspot JIT openjdk-8-jre-headless - OpenJDK Java runtime, using Hotspot JIT (headless) openjdk-8-jre-zero - Alternative JVM for OpenJDK, using Zero/Shark openjdk-8-source - OpenJDK Development Kit (JDK) source files uwsgi-app-integration-plugins - plugins for integration of uWSGI and application uwsgi-plugin-jvm-openjdk-8 - Java plugin for uWSGI (OpenJDK 8) uwsgi-plugin-jwsgi-openjdk-8 - JWSGI plugin for uWSGI (OpenJDK 8) uwsgi-plugin-ring-openjdk-8 - Closure/Ring plugin for uWSGI (OpenJDK 8) uwsgi-plugin-servlet-openjdk-8 - JWSGI plugin for uWSGI (OpenJDK 8) java-package - Utility for creating Java Debian packages
In this case, the wanted package will likely be the "openjdk-8-jre" package. Names of packages can be found on Debian's wiki pages or the packages site.
With the package name apt-get install can be used to install the prebuilt packages.
apt-get install openjdk-8-jre
# More than one package can be installed at a time.
apt-get install openjdk-8-jre nano vim mplayer
For more information on using apt-get refer to Debian's documentation here.
Debian Setting up SSH
To install the SSH server, install the package with apt-get:
apt-get install openssh-server
Debian Stretch by default disallows logins directly from the user "root". Additionally, SSH will not allow remote connections without a password or valid SSH key pair. This means in order to SSH to the device, a user account must first be created, and a password set:
useradd --create-home --shell /bin/bash newuser
passwd newuser
After this setup it is now possible to connect to the device as user "newuser" from a remote PC supporting SSH. On Linux/OS X this is the "ssh" command, or from Windows using a client such as PuTTY.
Debian 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. |