Difference between revisions of "CI20 Headless Setup"
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psk=<the WPA passphrase>
psk=<the WPA passphrase>
Revision as of 16:56, 17 August 2014
This page describes how to set up your CI20 board for headless operation. This is useful if you don't have an HDMI screen available or don't wish to use one.
Getting connected to the serial
The default NAND image uses the UART0 signals which are accessible from the main expansion header near the camera connector. Note that this header is compatible with the Raspberry Pi's expansion header, so much of the RPi Serial Connection article applies to the CI20.
The easiest approach is to purchase a USB to TTL UART adapter. Something like this would probably do (but don't connect the red VCC wire).
Connect the Ground, TXD and RXD wires to pins 6, 8 & 10 of the header. These are the 3rd, 4th and 5th pins on the row nearest the edge of the board:
+------------------------ + | 2 4 [6 8 10] 12 ... | | 1 3 5 7 9 11 ... | | ^ |
See RPi Serial Connection#Connection to a PC for help setting up the serial console.
When you plug in the CI20's power connector you will see text output on the serial console. This comes first from U-Boot, which offers you a chance to interrupt the autoboot in order to get to U-Boot's interactive prompt (from which you can load a different kernel).
If the autoboot is allowed to continue it will load and start the Linux kernel which will output its own boot log on the serial console.
Eventually Debian will present a login prompt:
Debian GNU/Linux 7 ci20 ttyS0 ci20 login:
The default username and password are both "ci20".
Setting up WiFi
One of the first things you may want to do is set up WiFi so that you can connect to the CI20 over SSH. However this is complicated by the fact you don't have access to the normal graphical interface.
The default Debian image has Network Manager set up, but unfortunately that version of the Network Manager command line tool (nmcli) cannot create a new WiFi connection, so you'll need to find another way.
You can scan for WiFi networks with nmcli, for example:
ci20@ci20:/etc$ nmcli dev wifi SSID BSSID MODE FREQ RATE SIGNAL SECURITY ACTIVE 'PlusnetWirelessXXXXXX' XX:XX:XX:XX:XX:XX Infrastructure 2412 MHz 54 MB/s 41 WPA WPA2 yes
Network Manager stores system wide connection information in /etc/NetworkManager/system-connections. You'll need to become root to add one (the default password is "ci20"):
ci20@ci20:~$ su Password: root@ci20:/home/ci20# cd /etc/NetworkManager/system-connections/
Write a new text file for the WiFi network using your favourite text editor. For example:
root@ci20:/etc/NetworkManager/system-connections# nano PlusnetWirelessXXXXXX
If you already have a Linux machine connected to the WiFi network, the contents of the file can come directly from that machine. You will however need to delete any "mac-address=XX:XX:XX:XX:XX:XX" line to allow it to connect.
[connection] id=PlusnetWirelessXXXXXX uuid=68f0fd52-cbb4-4f64-bbbb-65d5c6da68d1 type=802-11-wireless [802-11-wireless] ssid=PlusnetWirelessXXXXXX mode=infrastructure security=802-11-wireless-security [802-11-wireless-security] key-mgmt=wpa-psk psk=<the WPA passphrase> [ipv4] method=auto [ipv6] method=auto
Save the file and change the permissions so that only root can read it:
root@ci20:/etc/NetworkManager/system-connections# chmod 0666 PlusnetWirelessXXXXXX
Now restart Network Manager:
root@ci20:/etc/NetworkManager/system-connections# /etc/init.d/network-manager restart
You can check that the connection was valid by checking that nmcli can see it:
root@ci20:/etc/NetworkManager/system-connections# nmcli con list NAME UUID TYPE TIMESTAMP-REAL Wired connection 2 63f0b880-1003-414a-8798-95492d5b1e77 802-3-ethernet Mon 18 Aug 2014 00:45:11 BST Wired connection 1 6fec7fea-803b-4112-ac6f-e24be941cd09 802-3-ethernet Mon 18 Aug 2014 00:45:11 BST PlusnetWirelessXXXXXX 68f0fd52-cbb4-4f64-bbbb-65d5c6da68d1 802-11-wireless Mon 18 Aug 2014 00:45:16 BST
And if your configuration is correct it should automatically connect to the WiFi network:
root@ci20:/etc/NetworkManager/system-connections# nmcli dev DEVICE TYPE STATE wlan0 802-11-wireless connected usb0 802-3-ethernet unavailable eth0 802-3-ethernet unavailable
You may be able to see the CI20 from other devices on your network. If not you can use /sbin/ifconfig to find its IP address.