Parallel Graphical LCD palette - Page 1
Forum section: electronics / beginners

author: pyromaniac4382
author_rank: Contributor
timestamp: March 12, 2016, 02:08:17 am
content: I was wondering if anyone had any experience with parallel graphical LCDs that have some sort of palette. It seems like you can easily get a parallel graphical LCD on the internet with only one static color such as white 'pixels' on a black screen, but none ever seem to have any palette options. By palette options I mean something similar to how the original Nintendo GameBoy worked. This screen has a '4-color' palette, but its colors were only different intensities of a lit pixel as far as I know. Does anyone know of a similar scheme to this? I was hoping to be able to get some sort of screen to work with some older 8-bit stuff, but everything seems to be tailored to serial protocols these days. Thanks.

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: March 13, 2016, 01:05:22 am
content: Most of the TFT LCD modules you can buy on ebay support a parallel protocol. It can work in either 8- or 16-bit mode, depending on how a select pin is tied. These don't have a palette, instead directly accept RGB values (16-bit rrrrrggggggbbbbb or 18-bit rrrrrrrrggggggggbbbbbbbb).Here's one I've used:http://www.elecfreaks.com/estore/2-8-tft-lcd-tft01-2-8.html

author: bktemp
author_rank: Super Contributor
timestamp: March 13, 2016, 10:08:34 am
content: You can get LCDs with RGB backlight. The LCD can only do black and white, but you can select any backlight colour if you apply PWM to the RGB leds.Most modern TFT-LCDs can display at least 262144 colours, but its interface can often be switched to a reduced number of colours like 65536 or 4096.

author: Buriedcode
author_rank: Super Contributor
timestamp: March 14, 2016, 09:06:41 pm
content: The older colour LCD's, specifically CSTN (colour STN) used an 8-bit interface that was a bugger to use - RGBRGBRG... BRGBRGBR .. GBRGBRGB (first 8 pixels, only 3-bits per pixel). One would usually use a dedicated controller for such a display, such as the Solomon Systech SSD1906 which acted both as the controller, frame buffer, and contained programmable colour palette's. Different colours were achieved with frame PWM, and dithering (as it was a passive display, pixels can only be turned on or off). I believe the gameboy display had a controller that did something similar built into the flex cable.I implemented my own controller than barely fit on an XC95144XL cpld. Totally not worth the hassle.Since TFT's have become ubiquitous and cheaper, and MCU's have got larger, cheaper, even with graphics controllers (the basic frame buffer/refresh) built in, there generally isn't much call for external graphics controllers or making displays with built-in colour palettes. As TFT's just have that parallel interface for each pixel, the user has full control over colour directly.If you want to use a TFT in your 8-bit projects, I'm sure there are 8-bit/arduino friendly TFT modules that have the TFT display and a built-in MCU to handle the nitty gritty - colour pallete, shapes, lines text etc.. Or you could roll your own with a 32-bit device, but then you might as well use that for your projects eh

author: pyromaniac4382
author_rank: Contributor
timestamp: March 15, 2016, 12:52:37 pm
content: Thanks for all the replies. I guess TFT-LCDs are the way to go then. By older 8-bit stuff I mean I am in Z80 & 6502 land and not in Arduino land. I am going to try to experiment on a parallel TFT-LCD and see if there is enough memory for the display otherwise I think I am going to just settle for those one-shade graphical LCDs. It seems odd with the Gameboy being so popular back in the day that those types of LCDs did not become a electronics staple.