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Controller ICs
Background
Generally, Kyocera LCD modules have a low level interface. To display anything, on/off bits must be sent for
each RGB subpixel on a row and this process repeated for each row of the LCD module. The complete screen image
must be re-displayed over 60 times per second. On the other hand, engineers designing real-world systems will
want to be able to place an image with 256 or more colors in memory and update that image only as their
application requires. Some kind of freestanding process is required to resolve these dramatically different
requirements. The easiest solution to visualize is a discrete controller IC. Alternatives include a discrete
FPGA or a LCD control module executing on a fast microprocessor. Embedded Systems Programming discusses this
and related issues in an article titled
GUI add-on options and it
discusses programmming it in an articles titled GUI Development: Embedding Graphics
Part I and
Part II.
This web page partially describes several controller ICs. The descriptions below are only partial because
these controller ICs are not Kyocera products. Kyocera will try to be helpful by describing how to
configure a controller IC for particular LCDs and by giving links to the controller IC's site.
C&T LCD Controller ICs
Asiliant Technologies is the new home for the Chips and Technologies family of Flat-Panel Display Controllers.
They are continuing to manufacture and sell the 65545 and 65550, which are widely used to control Kyocera LCDs
in single-board computers. They can be reached at www.asiliant.com.
Silicon Motion LCD Controller ICs
The SM712 is widely used in single-board computers, but it does not support single-scan STN. It does support
double-scan STN and TFT LCDs. Kyocera double-scan LCDs are only 640x480 and above and can be identified by
16 data inputs with names beginning "HD_" and "LD_". Silicon Motion can be reached at
www.siliconmotion.com.
Epson LCD Controller ICs
Epson has been providing a family of controller ICs for many years. Visit
www.erd.epson.com for complete controller IC product
lists, specifications, evaluation utility software and drivers for many operating systems. Incidently,
Embedded.com has published
A survey of Linux device drivers which includes sample code that configures an Epson S1D13xxx LCD
controller chip.
Epson has changed the model numbers of the controller IC's.
In the following table, the old model numbers are shown in parentheses. In the clickable Kyocera documents,
both old or new model numbers may be used.
The common documents below apply only to STN LCDs. They also contain a misunderstanding of the Epson PCLK frequency as applied to STN LCDs. The CP (or shift clock) frequency as seen by the STN LCD is actually only 3/8 of the PCLK frequency which drives the controller IC (CPfreq = 0.375 * PCLKfreq). For each pixel read into the controller IC, it must write 3 sub-pixels to the LCD, but the subpixels are retained until 8 subpixels can be written at once on the 8 STN LCD data lines.
Epson makes other controller ICs which certainly work fine with at least some Kyocera LCDs. They are not listed above because Kyocera has not operated them or studied their specs. When working with other Epson controller ICs or other Kyocera STN LCDs, use the following guidelines to select the correct options in the Epson configuration program.
- STN
- Color
- Format 2
- FPline Hi
- FPframe Hi
- Width and height in pixels, exactly according to LCD spec
When the Kyocera LCD has 8 data inputs
(typically named D7...D0) then select
When the Kyocera LCD has 16 data inputs
(typically named HD7...HD0 and LD7...LD0) then select
Any other options should be in accordance with the Kyocera Spec.
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