Cubieboard/TTL

WARNING: DO NOT CONNECT THE RED LINE TO VCC.

Connection
If you get a USB-Serial adapter from somewhere else, please check the cable colors of it at the vendor. RX pin on adapter should be connected to TX pin on cubieboard and adapter TX pin vice versa, so a serial wires are crossed.

The CubieBoard (Rich package) is currently supplied with a Prolific PL2303 USB cable. This cable provides VCC power on the red cable. The Cubieboard does NOT require power (red cable), and it may damage your board if connected. The CubieBoard provides a pin header with 4 pins for TTL UART connection. If you are using the supplied PL2303 cable, then the connection should be as follows:



WARNING: DO NOT CONNECT THE RED LINE TO VCC.

Availability

 * http://www.aliexpress.com/store/product/TTF-to-USB-Serial-line/511685_665830339.html
 * https://www.adafruit.com/products/954

Linux Driver
Driver for the PL2303 is inside the kernel. It will work with default settings.

OS X Driver
The opensource driver on github works and the binary version is on the link below.

It is at least confirmed to work on Mac OS X 10.6.8 32 bit version.
 * https://github.com/downloads/berg/osx-pl2303/osx-pl2303-0.4.1-failberg.pkg (could someone confirm that this works?)

There is also a vendor-made driver;


 * Go to http://www.prolific.com.tw/US/index.aspx
 * Click support
 * Login with GUEST / GUEST
 * Click on "click here for PL2303 USB to Serial drivers"
 * half way down, download the file md_PL2303_MacOSX10.6_dmg_v1.4.0.zip

Windows Driver
Windows Driver for Prolific PL2303 is installed automatically. If your "Device Manager" mark the PL2303 device (Prolific USB-to-Serial Comm Port) with yellow exclamation mark and the status of the device shows "code 10", then you probably got counterfeit (fake) cable or you are using the cable with Windows 8. In both cases you just have to install older version of Prolific drivers (1.6.0, 1.7.0, 1.8.0 or later won't work).


 * For PL2303 HXA, XA (to check your version use the utility provided in latest Prolific drivers.)
 * Installer version & Build date: 1.5.0 (2011-10-21)
 * Windows XP (32 & 64-bit) WDM WHQL Driver: v2.1.27.185
 * Windows Vista/7/8 (32 & 64-bit) WDF WHQL Driver: v3.4.25.218
 * Files:
 * PL2303_Prolific_DriverInstaller_v1.5.0.zip (SHA-1 8b1e1a8b0ee5939ff2fb185690ec038f191dbcde)
 * PL2303_Prolific_DriverInstaller_v1.5.0.exe (SHA-1 43fe44b600586e9b41088ba1be5b4eee96c7dc23)
 * Download (Mirror #1, #2)

Linux
cu is an utitlity that comes with popular system distributions like Fedora, Debian, Ubuntu, NetBSD, etc. It can be used to talk to a device connected to a serial port. On Linux with the serial cable as the only USB serial port

stty -F /dev/ttyUSB0 -crtscts # turn off hardware flow control - the cable has no wires for that cu -s 115200 -l /dev/ttyUSB0

should show the u-boot and kernel messages from cubieboard.

Another option is GNU screen

screen /dev/ttyUSB0 115200

With gtkterm, a serial terminal tool with minimum graphic interface :

gtkterm -p /dev/ttyUSB0 -s 115200

Troubleshooting
You might get the following error when trying to access the serial port

$ sudo cu -s 115200 -l /dev/ttyUSB0 cu: open (/dev/ttyUSB0): Permission denied cu: /dev/ttyUSB0: Line in use

The reason why you cannot access the serial port even if you are root, is due to additional kernel-level security restrictions (such as AppArmor or SELinux). For the case of Ubuntu, which has AppArmor, your account needs to be member of the group dialout. To add your account to the dialout group, run the command

$ sudo usermod --append --groups dialout myusername

Then, log out and log in again.

Windows
On Windows you can use software like TeraTerm or Putty or similar which can connect over serial line.

Configuration
It seems the default setting for uBoot and terminal serial is 115200 8N1: Windows users can determine proper COM port from Device Manager.

Sample output
See http://pastebin.com/p77V8xdC for sample output. It shows the boot process of the Cubieboard.