Can the Propeller control this LCD panel?
John P
Posts: 5
I have a couple of LCD panels, Sharp model LM8V311. This panel has 640 x 480 pixels, but it's a color unit and effectively, each pixel is in triplicate, for the RGB colors. So you could call it 1920 x 480 pixels. The arrangement of the colors isn't helpful; the unit has to be fed with a byte at a time, and the bits of a byte represent the R, G, B subpixels in rotation, so the first byte is RGBRGBRG, the next one is BRGBRGBR, and the third one is GBRGBRGB, after which the sequence repeats; after 3 input bytes, data for 8 pixels would have been loaded.
Two bytes have to be fed in at a time, for upper and lower half-screens, with timing signals for the end of each line and the end of a full screen. I'm not totally clear on how rapid a screen time needs to be, but it seems to be somewhere from 75Hz to 120Hz.
The amount of data needed for a screen seems to be 640 x 480 x 3 / 8 bytes, or 115200 bytes. That appears to be a lot more than the Propeller can hold internally, but there's the possibility of controlling external memory.
If anyone's interested enough in this to want to see a data sheet, it's available in PDF form here:
http://datasheet.digchip.com/424/424-06349-0-LM8V311.pdf
So anyway, my question here is whether the Propeller can control this LCD without a totally unreasonable amount of external hardware. What I'd like to be able to do would be to create a few graphic commands, to draw lines and rectangles and display text, in any of the 8 colors selectable with 3 bits per pixel. If the Propeller can do it, I'd consider buying some and learning to use them.
p.s. Sorry to have initially posted this messaqe with no title. I thought I had one, but it must have escaped while my attention was elsewhere.
Post Edited (John P) : 4/22/2009 12:14:53 PM GMT
Two bytes have to be fed in at a time, for upper and lower half-screens, with timing signals for the end of each line and the end of a full screen. I'm not totally clear on how rapid a screen time needs to be, but it seems to be somewhere from 75Hz to 120Hz.
The amount of data needed for a screen seems to be 640 x 480 x 3 / 8 bytes, or 115200 bytes. That appears to be a lot more than the Propeller can hold internally, but there's the possibility of controlling external memory.
If anyone's interested enough in this to want to see a data sheet, it's available in PDF form here:
http://datasheet.digchip.com/424/424-06349-0-LM8V311.pdf
So anyway, my question here is whether the Propeller can control this LCD without a totally unreasonable amount of external hardware. What I'd like to be able to do would be to create a few graphic commands, to draw lines and rectangles and display text, in any of the 8 colors selectable with 3 bits per pixel. If the Propeller can do it, I'd consider buying some and learning to use them.
p.s. Sorry to have initially posted this messaqe with no title. I thought I had one, but it must have escaped while my attention was elsewhere.
Post Edited (John P) : 4/22/2009 12:14:53 PM GMT
Comments
Good luck.
I've also got a mono LCD running--did you get yours at All Electronics, by any chance?
http://www.allelectronics.com/make-a-store/item/LCD-104/640-X-480-LCD-W/-CCFL-BACKLIGHT-AND-INVERTER/-/1.html
I paid $11 for this, but they've cut the price to $6. That's a sweet deal, if you can get it working. My design involves a PIC processor with the display data stored in DRAM. It works very nicely, but it was a complex project in both hardware and software.
Insert emoticon for "apprehensive".
You should get a Propeller in any case. Regardless of whether it'll work with your color LCD, it's a ton of fun to play with.
As you noted the prop does not have enough memory for a display of that resolution, but it could control an external memory and counters to do so.