Gadget Factory forum user Alex received a junked old Hitachi screen from his buddy and decided to see if he could get it up and running. The screen is one of those older monochrome, low-resolution (256 x 128) green LCDs and is missing a controller chip. On the back of the display there are eight Hitachi LCD drivers, six column shifters and two row shifters. With no controller chip, the screen could not be driven in a static mode where you could just write image data to the internal memory. Instead, Alex had to figure out a way to use the LCD more like a VGA display where you must constantly send it data to refresh the picture.
Appropriately enough, Alex chose to use a cropped version of Lenna which has become a standard for image processing benchmarking.
To assist in getting this project off the ground, Alex found some applicable documentation:
I couldn’t find a datasheet for it or pinouts so I went old school and tracked down datasheets for the chips on board and did some reverse engineering of the schematic using a continuity meter. A very good datasheet resource is the “Hitachi LCD Controller Driver LSI Data Book” which is a compendium of a large number of Hitachi LCD controller chips.
Cool project, Alex! I guess that display still has some life in it after all. Comments section is open, so fire away if you’ve got anything to add!
(via the Gadget Factory forums)
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