Need help interfacing TFT display with a controller

[deenadayalan]

Hi,

I am using a AT056TN52 v3, bought it from a chinese firm (Innolux).
it has a driver board with actel proASIC3 FPGA. i don't know if the FPGA is already programmed or not ( asked the manufacturer, they said "IT WORKING" and sent me some timing diags. i tried interfacing based on that, nothing happened, and sent a lot of data via rs232 the tft won't even budge.

FYI, the tft is 640x480. the controller i use is pic16f877a(pretty obsolete and incapable of handling this tft but the driver board has 8bit data pins.
B0,B1,G0,G1,G2,R0,R1,R2)

IF u guys have already worked on something like this, your suggestion is welcome.

the pins i was told by the manufacturer to handle are the pins on the driver board. ie. (1-GND,2-GND,3-VCC,4-RD,5-WR,6-CS,7-RS,8 to 15 data pins (the pins i mentioned above), 16 - busy pin)
All pins are triggered at low level)

[Ttelmah]

Seriously, you haven't got a hope....

There must have been something more 'said' about the display when you ordered it. Without data, chances, minus one out of ten.

The FPGA, can be programmed to provide a variety of processor cores, and every bit of the I/O, and what is sent here is going to be totally dependant on what is in the ASIC, and even what ASIC it is (there are at least 9 versions of the proASIC3....). However none has enough RAM to directly drive a display of this size. If there is a RAM on the controller as well, things get a little more hopeful....

With data, you might be able to generate something.

Data should always be the first 'port of call'.

[temtronic]

Not quite as pessimistic as Mr. T. but really you could spend YEARS trying to decode the mystery of how to make it work! BTDT. I HAD to do a similar 'reverse engineering ' task 20 years ago BEFORE the WWW,that's how I got into using PICs. Needed fast, cheap, plentiful micros to design interface to decode what the 'board' needed to interface to it.
Frankly today,the board you have is 'landfill'. Though I did find a PDF for the actual display, YOU need the FPGA info. Maybe, just maybe the Net will find something about it BUT the module you bought could easily be a special production unit for a custom piece 'black box' (say a BP monitor,oil rig location,well gas unit,??)
Those 8 pins look like 3 for Red, 3 for Green, 2 for Blue...if so, then WHERE'S the 3rd Blue pin as well as 'pixel pointers or say HSync, Vsync?
Without knowing the application for the display it's hard to advise you which route to go. I know I can buy a 7" LCD screened 'tablet' for $50.Add some 'front end' code and it becomes a wireless LCD screen. Have you PIC (not an 877 BTW) interface to a WIFI module that talks to the tablet. A fairly simple task FAR EASIER to actually accomplish than wasting years of your life on the original LCD module. Other options include surfing the Web to find 'RS232-LCD' interfaces or complete 'RS232-LCD' unit. Must be TONS of that kit around these days.
So I'd spend time on the web and not on the one you have.

hth
jay

[Ttelmah]

It might well be that the diagrams he has been given do provide the 'core clue'.
Perhaps he can post a link?.

However with your 'reverse engineering', I'm guessing you actually had a working device driving it?. Problem is that with no data at all, (and especially with no details of the code in the gate array), the permutations are approaching infinity. Even the smallest of those arrays is something like 5000 gates, and with no details at all of what signal drives are expected, there is no starting point at all...

Thing is that the letters in the data lines, suggest that possibly this is just colour data, but if so, as you say, what says 'where' it is to go (RS, could be 'register select', so address, versus data), but then you have what is needed as a command?. Back to near infinite permutations. Other useful data would be what it was used for.

It could be 8bit, with only two bits for blue (some systems do use reduced colour depth to save bits). However where is this going to be stored?. One thought would be that there is a RAM, and it is as simple as dropping RS, CS, and WR, then sending the address you want to write, as three bytes, perhaps pulsing WR for each, then switching RS, and sending the data for this address, and sequential addresses if required, again pulsing WR for each. If so, I'd expect the diagrams to make this clear.

Without data, I'm back to your 'landfill'...

[Jerson]

I found this datasheet relevant to the display in question.

http://www.bdtic.com/DataSheet/Innolux/AT056TN52-V3.pdf

Looks a pretty tough job making a tiny PIC to handle this timing requirement and 24 bits.

[Ttelmah]

The 'display' is not the problem.....
Every replier has found the data sheet to this.

Problem is that it comes with a driver board, designed to generate the timings using a gate array, but he has no details on this at all, except (possibly) for some diagrams sent by the manufacturer (which he hasn't posted).

[temtronic]

OK I got bored, no pun intended, and found a few google hits for the 'board', here's one.
http://www.aliexpress.com/item/At056tn52-v3-driver-board/1275252784.html

Too bad it's a poor image but might be what he has. Appears to be the 'interface' board to a 5.6" LCD module.
sad thing is there is NO documentation and when you add in an LCD($50) you've got almost $100 into something that can never (easily) work making my original idea of using a $50 tablet (with BIGGER screen) a viable alternative.
I'm sure there must be several 'off the shelf' display/touch screens on the market but this unit is NOT one of them. Way too much time would be lost forever trying to get it 'up and running'.

jay

[Ttelmah]

If you go to the store linked from that listing, it makes your suggestion that this was a custom board for a specific piece of kit even more likely. Several of the other displays there are replacements for equipment.

What is perhaps interesting, is that the poster has asked exactly the same question on an Arduino board as well.