Out of the depths of a junk drawer, [Alex]’s friend pulled out an old monochrome LCD display. This is an older low-resolution display from ancient electronics that unfortunately doesn’t have its own controller chip. No worries, though, because with the help of an FPGA [Alex] figured out how to drive this display.
On the back of this display are eight Hitachi LCD drivers, six column shifters and two row shifters, allowing the LCD to display a 256×128 pixel image. Without an LCD controller, though, [Alex] couldn’t just send a static image to the LCD. Instead, he had to continuously refresh the display just like a VGA monitor.
With the help of a 1500-page PDF titled Hitachi LCD Controller/Driver LSI Data Book, [Alex] was able to dump pixels into the ICs on the display with the help of a Papilio One FPGA board. A lot of work just to display the beautiful [Lena], but she wouldn’t have it any other way.
Neat project. It’s kind of cool to see how Hitachi later developed the HD44780 to interface with these screens. The manual is just as brutal too!
Good stuff! I have a couple of LCDs that I want to try this sort of thing with. One’s out of a very old, scrapped Gould instrument of some sort, and the other’s out of a Psion 3a organiser (with a broken FPC).
nice !
LENA !!!! :D
I did something similar using a microcontroller. The trick is to use a DMA-capable SPI peripheral to send an entire frame to the display. The DMA end of stream interrupt just starts a new DMA transfer so the screen is continuously refershed.
As the interface to those displays (at least, mine) isn’t SPI, but 4-bit parallel I used some glue logic to partially deserialize the data stream, and generate VSYNC and HSYNC.
It’s documented here: http://www.webalice.it/fede.tft/spi_as_lcd_controller/spi_as_lcd_controller.html, and I’ve submitted it to hackaday a while ago, but for some reason it wasn’t featured.
LIKE.
Very cool :) I knew there was a reason for my “Random Screen” drawer :) Great job!
You know, I’d really like to see a tutorial or something on how to use old LCD screens for your own purposes. I’m sure we all have a lot of old cellphones lying around with perfectly useable screens in them. I can never bring myself to throw them away.
Dang kids these days and their fancy FPGAs. This particular panel looks like it already has the traces for a Hitachi CPU interface controller on the back, likely an HD61830 or the like. A GWS for the driver chips yields http://mazsola.iit.uni-miskolc.hu/ftp/unix/lcddabo.pdf as the 7th hit. The chips might be hard to find but one could maybe be cannibalized, or just find a cheap 256×128 panel that already has one, they are common.
The 61830 can be driven by a PIC or a 6502 rather than requiring an FPGA. I don’t want to diminish the hack status of this post, but it seems people these days want to just throw hardware at a problem rather than consider the original design.
An HD61830 is $10 on Ebay. Other than that its a ram chip and some passives.