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View Full Version : Anyone Try Sparkfun's 3.5 TFT LCD ?



jazzed
04-23-2008, 10:51 PM
Thinking about trying this one. Anyone have experience with it?
http://www.sparkfun.com/commerce/product_info.php?products_id=8490


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jazzed·... about·living in·http://en.wikipedia.org/wiki/Silicon_Valley (http://en.wikipedia.org/wiki/Silicon_Valley)

Traffic is slow at times, but Parallax orders·always get here fast 8)

Rayman
04-23-2008, 11:35 PM
I thought about that one but then decided it would be cheaper and easier to just use a NTSC LCD...

jazzed
04-23-2008, 11:52 PM
Got a pointer to an NTSC LCD source?
(Still looking for feedback on original question.)

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jazzed·... about·living in·http://en.wikipedia.org/wiki/Silicon_Valley (http://en.wikipedia.org/wiki/Silicon_Valley)

Traffic is slow at times, but Parallax orders·always get here fast 8)

Win
04-24-2008, 06:54 AM
I haven't tried the Sparfun LCD, but Parallax sells a nice compact composite LCD for
about $80 or $90. Or you can try rolling your own for about $25. This was in an earlier
thread, but see this link for what I did. There's a link there to the instructions too.
http://wsh.homeunix.org:8080/~izzy/Site/Blog/Entries/2008/4/6_CyberHome_mini_DVD_Monitor_Hack.html
Works well.

Win

Oldbitcollector (Jeff)
04-24-2008, 07:20 AM
The link to that homebrew monitor is:

www.orrtech.net/propeller/cyberhomedvdplayer.html (http://www.orrtech.net/propeller/cyberhomedvdplayer.html)

But you will have to buy them from Ebay, as I don't think geeks has them anymore.


OBC

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Timothy D. Swieter
04-24-2008, 11:59 AM
COnnecting a Propeller to a TFT display, like the one linked to at SparkFun, isn't a good idea for the Propeller. One of the main reasons is the memory. If you are wanting to do a graphics driver or something similar, the memory gets to be the big problem. The Propeller has only so much ram to work with. The TV or VGA drivers work well, but also do some tricks to try and minimize memory. I suppose those same tricks could be used for the TFT as well.

I have been working with the uOLED and soon another OLED screen. At the moment I don't see speed in writing to the display an issue as much as the video memory in the Propeller.

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Timothy D. Swieter

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Ken Peterson
04-24-2008, 07:59 PM
I think it's possible to drive a parallel RGB display with a modified VGA driver. The overall timing is similar, but you would need to produce a dot clock signal (by using PLL mode 2 or 3 instead of 1) and perhaps change some of the other signals. You will only get two bits per color, however, with one cog. ·If that's all you need then it's theoretically doable. If you need more color depth you can use more cogs but you will quickly run out of memory for the screen buffering (see Timothy's commments).· In order to drive 8 bits RGB with 2 bits from the Propeller, connect MSB to bits 7,5,3 & 1 and LSB to bits 6,4,2 & 0 in order to gain maximum color range on the display.

This is something I have considered trying, but I have not yet had the time to do it.· Also, some LCDs need to have constantly alternating voltages on the drive signals. I'm not sure I understand how this is supposed to be done. This one may not need that.

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Post Edited (Ken Peterson) : 4/24/2008 1:05:17 PM GMT