Welcome to Gumstix 101: Your guide to using a Gumstix computer-on-module (COM) effectively and efficiently.
If you're new to using Gumstix products, just getting started with Linux, or simply need a refresher course, you've come to the right place!
Let's begin with these tasks:
- Mounting a Gumstix COM on an expansion board.
- Making connections with your Gumstix expansion board, including connecting monitors and USB peripherals.
- Booting your Gumstix system and touring the desktop.
Upon completion, you will be ready to develop with your new Gumstix COM. For further development and more advanced product applications, a series of How To(s) can be found in the side bar. These tutorials address how users can create a bootable microSD card, establish a console connection, install new packages and much more.
Mounting a Gumstix COM to an Expansion Board
The typical Gumstix configuration consists of a computer-on-module or COM and an expansion board.
- The expansion board can be off-the-shelf from Gumstix or custom made. Gumstix openly publishes the schematics of all off-the-shelf expansion boards to assist rapid development of custom solutions.
- For some applications, a camera board can be connected to the top of the Overo COM via a ribbon cable.
- A typical verdex pro assembly consists of a verdex pro COM sandwiched between a 60-pin expansion board and an 80-pin expansion board.
The DuoVero COM, Overo COM and Verdex Pro COMs are unique to Gumstix. Many off-the-shelf COMs and expansion boards can be purchased through Gumstix, and each Gumstix COM supports a wide range of custom designs.
A fully configured Gumstix Overo COM:
The following addresses the most common expansion options: an Overo COM mounted on a Tobi expansion board, an Overo COM mounted on a Gallop43 expansion board and a verdex pro COM mounted on a console-vx expansion board. If the specific option you are configuring is not presented, please note that many expansion options connect similarly. Follow along to find the one that best suits your situation.
Overo & Tobi
An Overo COM connects to an expansion board via the two 70-pin connectors located on the bottom side of the COM. Place the Tobi board on a flat, static-safe surface, align the COM with the white outline on the board above the connectors and gently press on the COM until it clicks into place.
DuoVero & Parlor
A DuoVero COM connects to an expansion board via the two 70-pin connectors. Place the Parlor board on a flat, static-safe surface, align the COM above the connectors and gently press on the COM until it clicks into place.
Verdex Pro & Console-VX
A verdex pro COM connects to an expansion board via the 80-pin connector. Place the Console-VX board on a flat, static-safe surface, position the verdex pro COM over the board so the white connectors are aligned and gently press down until the connectors are fully mated, i.e. completely seated.
Connecting a Gumstix Computer
Now that you have connected the motherboard to the expansion board, we can begin connecting to the outside world.
Console VX connections
Booting Up a Gumstix Computer
With all the peripherals attached, plug in the wall adapter and power on your board. You will see a few lights flash, and though little may appear to be happening, the Gumstix COM is loading. "Under the hood" U-Boot bootloader is preparing to load the operating system by signaling the processors. Illuminated on the screen are steps for the Gumstix Linux Angstrom distribution. The details will differ based on operating system, most will be running Ubuntu or Android, but the fundamental steps are similar.
As the linux kernel loads and initializes the hardware, Tux, the Linux penguin will appear on the screen. A white splash screen then indicates that the kernel has booted successfully and is passing control over to a userspace startup manager such as Sysvinit. Finally, you will see a screen desktop pop up. If this is the first time, there will be a few prompts regarding the configuration such as language preference and the icon you'd like to see on your desktop. For example, with touch screens you may be asked to help calibrate the display.
Setting up your Overo configuration for a console session
A detailed guide can be found by following this link: Setting up a Serial Connection
The simplest way to set up your Overo computer is with a console session, using your laptop or PC as the terminal. This requires only two connections, power and a USB.
First, pick up your Overo COM and turn it over. You will notice that the 70-pin connectors are not equally positioned on the bottom surface. One 70-pin connector is closer to the shorter edge than the other connector. Align the 70-pin connectors of your Overo COM with the 70-pin connectors on your expansion board and then gently snap the Overo COM down onto the two 70-pin connectors of that expansion board.
The Summit expansion board, like every Overo expansion board, has a console port containing an FTDI USB/serial converter chip. This chip connectes to the USB port labeled "USB CONSOLE" on the expansion board, allowing you to communicate with the Overo's processor serial port console. To do this, connect the Overo expansion board to your computer via a mini-B to standard-A USB cable and launch the terminal emulation program (115200 8N1, no flow control). These steps are discussed in detail in this guide.
Once the Overo boots successfully, you can begin to add peripherals. We will begin with a monitor, a USB keyboard, a mouse, and a network dongle.
Note: Before disconnecting any Overo COM from any expansion board, the shut down the Overo COM and disconnect power supply from the expansion board.
The Overo board will connect to your monitor via its HDMI connector. If your monitor does not have an HDMI input, you can use a HDMI/DVI-D cable. Your monitor should be able to support 1024 x 768 @ 60 Hz.
Note: Old style analog monitors will not work; the HDMI connector provides only digital signals.
Gumstix "Host" = USB High speed (480Mbit/s ONLY). You will need a hub to connect to most USB -> Serial adapters
Use the USB OTG port for connecting the keyboard and mouse via a powered USB hub. An unpowered hub will not work since the OTG port only provides 100 ma of power. Other, suitable, 3rd party USB hubs are listed on the Cabling and Compatible USB devices page.
Remember to use the proper cable to connect the USB OTG port on the Overo expansion board to your hub. We recommended that you use a cable like the USB Mini-B to Mini-A Adapter. Though a common USB Standard-A to Mini-B type cable will fit, it will not work. OTG ports require a cable that grounds the ID pin in order to enable the port to act in host mode.
Now, plug your keyboard and mouse into the hub.
Gumstix provides several demonstration videos for the Overo series. The video titled Overo/Summit connection illustrates the aforementioned process. You will see how to power up the Overo/Summit configuration and connect to an HDMI screen, complete with the keyboard and mouse. These can be seen in the video, and are cabled to the Summit board via a USB hub, however this aspect is not featured in the video.
If you have an expansion board without a 10/100 Ethernet jack, such as the Summit board, you may now plug in an Ethernet or WiFi USB dongle. The Overo kernel is built with support for many popular devices.
Customers with an expansion board that has a 10/100 Ethernet jack, such as a Tobi or Chestnut board, may plug their Ethernet cable into that expansion board.
Now that your peripherals are connected you can re-apply power to your Overo. Again, you should be greeted by a Tux boot screen, followed shortly thereafter by the Enlightenment window manager. The demo root file system includes browser, email, chat, word processor, and spreadsheet. MPlayer is also included for playing mp3's and movies.
A REMINDER TO UPDATE the PRE-INSTALLED SOFTWARE IMAGE to a CURRENT RELEASE
Due to manufacturing logistics, the image shipped with your Overo is likely several months old. We highly recommended that you update your software image to a recent release to ensure you have the latest features and bug fixes.
Please see the article on Downloading pre-built images.
LCD Panels (Palo and Chestnut Boards)
If you are using one of the Gumstix LCD Panels (Palo or Chestnut), you will need to modify the default display variable in your u-boot environment to let the kernel know to use the appropriate LCD panel driver. To do this, interrupt the autoboot sequence by pressing a key when you see the following prompt:
Hit any key to stop autoboot: 5
Then type the following at the u-boot prompt:
setenv defaultdisplay lcd43
Or, if you are using a 3.5" screen (such as the LCD panel with the Palo35):
setenv defaultdisplay lcd35
You can save this setting for future boots by saving it:
Note: If your COM has no NAND flash, it is not possible to save environment variable. To support particular boot configurations such as 'lcd43' on Tide, Sand and other with no NAND, it is necessary to compile u-boot after altering the include/configs/omap3_overo.h file. U-boot can be built using OpenEmbedded (bitbake virtual/bootloader) or directly.
Finally, instruct u-boot to continue with the boot process:
Gumstix videos illustrating connecting an LCD panel to an Overo configuration. Click on either link below to start the video in Youtube: