To establish a serial connection you will need an open serial port (or USB serial adaptor) on your development machine. You will also need a terminal program such as kermit or minicom.
To connect to the Gumstix console, you need a serial port, found on the tweener board or one of the console expansion boards. You will also need a null modem cable with appropriate connectors. Newer boards may have a built-in USB-to-serial chip and require only a USB cable.
Connecting with Kermit (Linux)
These directions are for the Kermit communications package (cKermit on Linux).
1. Connect a mini-B to standard-A cable between the CONSOLE port on the expansion board and a USB port on your PC (standard A). A green LED near the USB connector will illuminate. Do NOT connect power to the expansion board just yet.
If you have an older board, it may not have a direct USB connection. In this case connect the null-modem serial cable to the serial port on your computer and to the serial port on the Gumstix. For the console-vx board, use the middle port of the three present.
2. Launch kermit:
$ kermit -l /dev/ttyUSB0
where /dev/ttyUSB0 is the USB port you're using on the host computer. If you are using a serial cable, your serial port is likely /dev/ttyS0
3. Now set up the serial connection parameters and connect to the COM:
C-Kermit> take ~/gumstix/gumstix-oe/extras/kermit-setup
If you don't have the "kermit-setup" file, then you will need to set the serial settings manually:
$ kermit -l /dev/ttyUSB0 C-Kermit>set flow-control none C-Kermit>set carrier-watch off C-Kermit>set speed 115200 C-Kermit>connect Connecting to /dev/ttyUSB0, speed 115200 Escape character: Ctrl-\ (ASCII 28, FS): enabled Type the escape character followed by C to get back, or followed by ? to see other options. ------------------------------------------
If you want, you can put these commands in a file called .mykermrc in your home directory to have them run automatically each time.
set line /dev/ttyUSB0 set flow-control none set carrier-watch off set speed 115200 connect
4. Connect to the port by typing connect
5. Plug the power adapter into any power jack on the Gumstix board stack. When connected and powered, you should see a message from U-boot followed by the normal Gumstix boot sequence:
Texas Instruments X-Loader 1.4.4ss (Oct 20 2010 - 10:10:28) OMAP3530-GP ES3.1 Board revision: 0 Loading u-boot.bin from nand U-Boot 2010.09 (Oct 20 2010 - 10:11:49)
OMAP3530-GP ES3.1, CPU-OPP2, L3-165MHz, Max CPU Clock 720 mHz Gumstix Overo board + LPDDR/NAND I2C: ready DRAM: 256 MiB NAND: 256 MiB *** Warning - bad CRC or NAND, using default environment
In: serial Out: serial Err: serial Board revision: 0 Tranceiver detected on mmc2 No EEPROM on expansion board Die ID #6c7800040000000004037f680d02100c Net: smc911x-0 Hit any key to stop autoboot: 0 I2C read: I/O error I2C read: I/O error No MMC card found Booting from nand ...
NAND read: device 0 offset 0x280000, size 0x400000 4194304 bytes read: OK ## Booting kernel from Legacy Image at 82000000 ... Image Name: Angstrom/2.6.34/overo Image Type: ARM Linux Kernel Image (uncompressed) Data Size: 3160068 Bytes = 3 MiB Load Address: 80008000 Entry Point: 80008000 Verifying Checksum ... OK Loading Kernel Image ...
....More text here....
The Angstrom Distribution overo ttyS2 Angstrom 2008.1-test-20080911 overo ttyS2 overo login:
6. Log in for the first time with username root and password gumstix. If the password does not work, try leaving the password field blank. If that fails, try the password root. The password may differ from image to image.
7. When finished, you can return to the kermit prompt by typing [CTRL-\] then pressing c. Type quit to exit the program.
Note: If you see the boot messages, but are unable to enter the login info, it is very likely that you neglected to disable hardware flow control in your terminal emulator setup
Connecting with Minicom (Linux)
- First, configure Minicom
- As root, run minicom -s
- Under "Serial Port Setup" choose the following
- Serial Device: /dev/ttyS0 (edit to match your system as necessary)
- Bps/Par/Bits: 115200 8N1
- Hardware Flow Control: No (this is important)
- Software Flow Control: No
- Hit [ESC] until you return to the main configuration menu
- Select "Save Setup as dfl" to save the default setup
- Select "Exit from Minicom" to exit the program
- Connect the serial cable to the serial port on your computer and the serial port on the Gumstix
- Run Minicom again with minicom -o. This tells it to skip all the modem initialization strings, which are unnecessary when communicating with the Gumstix. You may need to do this as root if your normal login does not have permission to access the serial port.
- Plug the power adapter into the power jack of the Gumstix. When connected and powered, you should see a message from U-boot followed by the normal Gumstix boot sequence in the minicom window.
- Log in for the first time with username root and password gumstix
- When finished, you can exit Minicom by typing [CTRL-A] then pressing Q. This exits without running the normal modem reset sequence, which will only send garbage to the Gumstix.
Connecting with Putty (windows)
1. First, plug in and power your Gumstix board (as above).
2. From Windows, you will need to find out which COM port on which your device will show. To do so, open the device manager. The fastest way to do this is via the Run dialog. Press Start->Run from your desktop or press Winkey->R from your keyboard. A small dialog box should pop up. Type in devmgmt.msc and then press enter.
3. Scroll through the device manager and expand the Ports section. When plugged in, your Gumstix board should show up. If unsure, you can unplug and replug the device.
4. Next, download Putty from here and run it. Set Putty to connect via Serial and set the speed to 115200. Make sure the COM port is set to exactly what you saw in the device manager.
5. Click on Open to connect to your device. You should now see a black box. Restart your Gumstix device by pressing the reset button. You should now see the bootup sequence.
6. Log in as in the Kermit tutorial.
Other Ways to Connect
By default, it is possible to connect to Gumstix COMs using SSH or VNC. Overo COMs will broadcast their presence on the mDNS; with the standard 'local' domain, you could connect to a single Overo on your local network via ssh:
$ ssh overo.local
COM modules run X11VNC to enable users to view the root desktop which is useful if you need remote graphical access to your computer. Note that X11VNC will display the first X display (i.e. 0.0) where many other VNC programs will display a new X display (e.g. 10.0).