Computers for industrial control and automation systems

Ethernet

Ethernet

All Pigeon computers have one Ethernet interface 10/100Mbit. The connection status is indicated by two LEDs built-in connector. Each Pigeon has assigned a unique 48-bit MAC address stored in EEPROM memory. The default system for Pigeon is set up to get an IP address automatically from the network via DHCP.

Check status of Ethernet:

ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:50:c2:b7:70:00
inet addr:192.168.1.14 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::250:c2ff:feb7:7000/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2080 errors:0 dropped:0 overruns:0 frame:0
TX packets:484 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:695976 (679.6 KiB) TX bytes:96478 (94.2 KiB)

GPIO6 is connected to RESET signal of Ethernet controller and USB hub (LAN9514 chip). RESET input assertion (low state) time must be a minimum of 1 μS.

LEDs

LEDs built-in Ethernet socket:

  • green - LINK - LED is on when a valid link is detected. LED blinks when transmit or receive activity is detected.

  • yellow - SPEED - LED is on when the Ethernet operating speed is 100Mbs, or during auto-negotiation. LED is off during 10Mbs operation, or during line isolation.

Static IP

A network configuration file is located at /etc/network/interfaces. A default configuration eth0 looks like the following (DHCP is used for wired Ethernet):

iface eth0 inet manual

To configure Raspbian with a static IP address manually for the Ethernet, edit /etc/dhcpcd.conf file:

nano /etc/dhcpcd.conf

and add following lines:

interface eth0
 static ip_address=192.168.1.111/24
 static routers=192.168.1.1
 static domain_name_servers=8.8.8.8

If you set static IP, you will need to manually specify a DNS server. To set the DNS server, edit /etc/resolv.conf,

nano /etc/resolv.conf

and add the following line:

nameserver 192.168.1.1

Replace 192.168.1.1 with the IP address of your DNS server.

IPv6

Raspbian support both IPv4 and IPv6. If you do not want to use IPv6 you have to add line:

net.ipv6.conf.all.disable_ipv6 = 1

in /etc/sysctl.conf file.

SSH

SSH server on Pigeon is enabled by default. You can disable the SSH server using raspi-config:

  • run raspi-config,
  • navigate to Advanced Options,
  • navigate to SSH,
  • select "Disable".

SSH root login on the Raspbian is disabled by default. To enable SSH login for a root user open /etc/ssh/sshd_config :

nano /etc/ssh/sshd_config

and change the following line:

PermitRootLogin without-password

to

PermitRootLogin yes

After that restart SSH server:

/etc/init.d/ssh restart

nmap

If you want to connect by SSH and you do not know IP address (serial console is not accessible) you can use nmap to find Pigeon IP address. To install on Mac OS or Windows, see the nmap.org download page. For example in Linux:

apt-get install nmap
nmap -sn 192.168.1.0/24

192.168.1.0/24 covers 192.168.1.0 to 192.168.1.255.

Pigeon MAC begins with "00:50:C2:B7".

ip-flash script

This script finds the first non-loopback IPv4 address and flashes it on the system LED (USER by default).

1 - 9 short flashes indicate the digits 1 - 9
10 short flashes indicate the digit 0
a long flash indicates an octet separator (dot)
a brief pause separates digits

The original version of the ip-flash script is here available.

If you want run script after boot:

wget https://raw.githubusercontent.com/kristech/pigeon-documentation/master/usage-guide/ethernet/ip-flash
chmod +x ip-flash
mv ip-flash /usr/bin/
nano /etc/rc.local

add

/usr/bin/ip-flash &

before exit 0.

Links

Back to Top