Frequently asked questions/LCD screens
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Customers using Gumstix OpenEmbedded should go to gumstix.net and the related user wiki
Note: all gumstix verdex motherboards available at gumstix.com are pre-flashed with OpenEmbedded.
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If your question is not in this FAQ, please feel free to ask it on the Mailing list
Is the Samsung screen touch sensitive ?
Yes, the Samsung LCD panel is a resistive touch screen panel.
For more on resistive touch screens, click here.
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What about LCD screens and the gumstix?
First, there is the LCD FAQ
Second, this Display page has more technical information on LCD screens and gumstix.
Third, the Selector Tool will assist in product selection.
Fourth, this eInk reader has gumstix inside.
Fifth, Polymver Vision is using the eInk technology in their Readius products.
Can the gumstix work with an LCD screen?
The LCD driver was working since back in Linux 2.6.10, using either the 8 bits per pixel mode (bbp) mode or the 16 bbp.
Some comments from one customer:
- I've just finished interfacing an EL panel from Planar which used the same interface format as an STN panel. My panel happened to have an extended tolerance for interfacing to 3.3V circuitry, so I didn't need anything else in between the panel and the gumstix. Check the specs on your panel's input voltage range. If your Vih min spec is above 2V, your're fine. If the Vih min spec is much above 2V, you might need a simple TTL level shifter to convert to the 3.8V or so that 5V TTL logic requires.
Which LCD screens/panels work with the gumstix?
The Gumstix's LCD controller can handle a wide variety of screens — monochrome, color, TFT - up to about 800x600, as long as it has a digital interface.
It seems that a good place to get LCD screens in single quantities is earthlcd.com — try
Earth LCD Store and click on "LCD panels"
Under the OEM section, there a several interesting choices. gumstix engineers have not tested these specific screens.
- Hitachi SX19V001ZZA - 7.5" Color STN 640 x 480 4096 CCFL - Price: $89.00
- Panasonic EDMGRB8KJF - 7.8" Color STN Touchscreen LCD - Price: $99.00
- Samsung UG24U01WGHT3A - 240x320 Transflective positive Graphic (monchrome) - EL Backlit FSTN - 3" PDA Touchscreen LCD (Includes Integrated Touch Screen) - Price: $39.00
- Sony 240 x 160 2.7" Color Reflective TFT Graphical Display with LED Frontlight (note: this has higher resolution than the au optronics display I mentioned earlier — this is really 240x160x3 colors, while the au one is more like 93x220 because it counts each color as a separate pixel) - Price: 1-19 $59, 20+ $49
- Optrex T-51963GD035J - 240x320 Colot TFT, LED Backlight. /etc/modules line: pxafb options=mode:240x320-16,active,hsynclen:100,vsynclen:1,left:20,right:0,upper:75,lower:2,pixclock:183000,hsync:1,vsync:1,outputen:1,pixclockpol:0
Which expansion boards allow me to connect an LCD panel?
In the past, gumstix sold the breakout SMT and the USB SMT expansion boards that could hook up an LCD screen.
How can the fpc cable be connected to the breakout-gs board - using a connector like digikey part #OR690CT-ND ?
Not all LCDs have the FPC type connectors. Many of the larger ones have a hirose connector similar to the gumstix connectors. For this kind of LCD, buy a cable that has the right hirose connectors. One end will plug right into the LCD. At the other end, cut the connector off and solder onto the breakout-gs through holes.
The pins on the lcd panels are in a different order from the breakout board holes. How can the connector be soldered such that the panel's pins and holes match correctly?
You don't have much choice other than making a small adapter board. Solder the FPC cable onto a small board with through holes like breakout-gs, and solder them to the right pins.
You asked which LCDs will work, most will because the LCD controller is flexible. How they are wired and configured depends on the type of LCD, since different types (TFT, STN, etc) use different signals.
