Author Topic: TFT LCD controller with built in drawing functions or rasterizer  (Read 3820 times)

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Offline thetooth

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I'm looking for an IC thats half way between a dumb 8080 mode frame buffer and a fpga GPU, from what i can find the only chips that meet my needs are something from 4D systems or the FT800(which still isn't mass production yet afaik).

The problem with these chips is:
  • 90% of their functionality is going to be wasted in my case, i don't need widgets or 3D and most certainly don't need audio
  • They both use serial interfaces so are inherently slow for any bit bang operations that aren't explicitly supported in chip
  • The cost is similar if not more than a DIY fpga implementation, which is the whole reason for looking at ASICs in the first place

What i actually need is a chip to provide a basic frame buffer to my STM32, and for more complex operations like fills or sprites(for text) i want the chip itself to carry out the task as its most directly in charge of the LCD and won't be wasting clock cycles on the main processor.

I can always go for a full software approach using a classic SSD1963, or if needed roll my own on an fpga(this shouldn't be terribly difficult or expensive since it mainly doing data translation and timing). Just wondering if someone knows a low cost controller that has a character generator and scanline polygon rasterizer built in.
 

Offline amyk

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Re: TFT LCD controller with built in drawing functions or rasterizer
« Reply #1 on: June 24, 2013, 11:44:23 am »
What resolution are you looking for? Solomon has some controllers with builtin graphics primitives (look at the SSD192x).
 

Offline thetooth

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Re: TFT LCD controller with built in drawing functions or rasterizer
« Reply #2 on: June 24, 2013, 11:51:45 am »
What resolution are you looking for? Solomon has some controllers with builtin graphics primitives (look at the SSD192x).
800xRGBx480.

I was previously using an epson controller with a 320x240 monochrome(4 shades) and the built in functions were such a good idea, it was actually being driven over 485 from an arduino at great speeds. It would be nice to have something similar at WVGA.
 

Offline mariush

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Re: TFT LCD controller with built in drawing functions or rasterizer
« Reply #3 on: June 24, 2013, 12:54:11 pm »
Sparkfun carries some 'smart' lcd screens .. you can upload pictures and stuff in the displays memory and some scripts/code in some proprietary language of theirs which also handles events triggers and stuff like that : https://www.sparkfun.com/products/11377
 

Offline legacy

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Re: TFT LCD controller with built in drawing functions or rasterizer
« Reply #4 on: June 24, 2013, 02:45:38 pm »
they have pretty lcd for Arduino, nothing special, but the LCD has an arm controller on board.
 

Offline Rasz

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Re: TFT LCD controller with built in drawing functions or rasterizer
« Reply #5 on: June 25, 2013, 11:09:40 am »
if $45 price point is ok stop looking for chips and just buy cheapest Android tablet, they all have USB host for fast connectivity.
Who logs in to gdm? Not I, said the duck.
My fireplace is on fire, but in all the wrong places.
 

Offline thetooth

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Re: TFT LCD controller with built in drawing functions or rasterizer
« Reply #6 on: June 26, 2013, 01:20:52 am »
Thanks for the suggestions, i don't think its worth wasting any time integrating an FPGA and learning how to use it so i'm going with the tried and true SSD1963, from what i've seen online with the plethora of demos people have created using the same chipset i intend to use and the performance isn't terrible.

One of the applications its going to be running is OSM based street navigation, which means drawing complex vector graphics over the entire screen and i thought to myself, why does the user need to drag the map around and pinch zoom? and the fact that the primary client is going to be couriers(which from my experience hate touch screens anyway) i don't actually need that stuff, so can get away with blanking the screen for 50ms in order to render an overview map with list of directions.

Also for those interested the code im using to nicely render objects is from: http://en.literateprograms.org/Polygon_Rasterization_(C) Its fairly quick, but i need to make some changes to the structure since its written as if it needs reflection(i.e. a copy of the framebuffer it can read from, not something that can be done in 512k SRAM :P) so that'll need to change to allow me to do one pixel per packet, instead of `send read cmd, store pixel data, modify, write back to lcd` ::)
if $45 price point is ok stop looking for chips and just buy cheapest Android tablet, they all have USB host for fast connectivity.
u wot m8?
 

Offline Rasz

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Re: TFT LCD controller with built in drawing functions or rasterizer
« Reply #7 on: June 26, 2013, 07:20:22 am »

if $45 price point is ok stop looking for chips and just buy cheapest Android tablet, they all have USB host for fast connectivity.
u wot m8?

You are building specialized hardware that can be easily replaced by cheap Chinese tablet + app + maybe an USB dongle to feed data.

http://dx.com/p/jxd-s18-4-3-resistive-screen-android-4-0-mini-pad-tablet-pc-w-tf-wi-fi-g-sensor-black-161536
Who logs in to gdm? Not I, said the duck.
My fireplace is on fire, but in all the wrong places.
 

Offline Synergy Hub

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4D Systems ( uLCD-43PT )
« Reply #8 on: October 10, 2013, 08:58:13 am »
I brought into the Lab a while back one of the 4D Systems controllers.   I have been having good success with it so far with it being an intelligent display / Process controller.   Has anyone else been using it ?
 


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