LMS298GF01 - Recycling a Phone Screen when you've no idea of it's heritage?

[jwhitmore]

Subject sort of sums up what I'm trying to do. Recycle a LMS298GF01 mobile phone screen. I can't even find out what manufacturer that is, so not sure who you'd ask a question of. Given that I can't find the company I'm sure that answering questions is not their forte anyhow.

without any information just a fine pitch 34 pin (2 rows on a flex cable) connector is there any way you could guess the interface to the screen?

OK it's a fairly ridiculous question, but it's a screen and it's begging to be used. Will the screen have an associated driver chip which will then communicate via SPI or something?

Thanks for taking the time to read.

[Cliff Matthews]

Always good to post an image.. LCD's are not one of my strength's but someone else may have an idea 


* edit - Nice, another from below, except your has another PCB I suspect..
Touch=obvious, COG=chip on glass, A=anode, K=cathode x4, and I'm guessing FOG=frequency on glass (power save)

[jwhitmore]

Well I can try, but I've not got much of a camera to hand.

[Yansi]

Most likely and LCD using a MIPI DSI interface.  Throw it in the bin where it belongs.

You better find yourself a different one, with a documentation available. LCDs are cheap nowdays. It is not worth the hassle to muck around with this mobile phone garbage nobody knows a bit about.

[jwhitmore]

It's a fair point, but when you know nothing about them you have to wade through so many choices trying to make a decision. When there's one just sitting there in the old crap bin it potentially saves all that effort. OK it's swings and roundabouts, six of one and half a dozen of the other.

I'll go find the complete idiots guide to interfacing a graphical screen to a micro-controller ;-) narrow down the options. A lot of cheap screens seem to be specifically targeted at the Arduino and its clones.

[Yansi]

No it does not. If you do not know much about LCD, the chance you will successfully reverse engineer one like that with a DSI interface is pretty slim. 

If you want to learn, start with something having a documentation available.

[james_s]

Looks like way too many pins to use a DSI interface, and probably too old for that. Most displays of that sort have a SPI interface, often there's also a parallel microprocessor bus interface. Not worth spending *too* much time messing with it when you can get similar displays brand new for a couple dollars each. If you had the original device it came from it would be much easier.

[amyk]

LMS241GF05 is made by Samsung, so I suspect LMS298GF01 is too. What other identification codes are on it?

Probably 16-bit parallel interface. 34 pins is pretty common.

[Old Printer]

I have a box full of old cell phones, no two alike. I agree, very frustration knowing you have a working display in hand but cannot work it. I have been down this rabbit hole a number of times and hit nothing but dead ends and get the same advice, If your time means anything buy one with documentation from a reliable source.

[jwhitmore]

Thank you all! OK OK , you've talked me out of it ;-)  I'm off to learn about screen technologies, with a nice simple SPI Interface.

I do have two of those phones, And I might just have a look to see if I can identify if there was a driver chip associated with the display. But I'll leave it for now.

thanks again

[james_s]

If you have the phone and a logic analyzer, you can sniff the signals to the display and see how it works.

Looking at the photos again I see more than one display. One of them looks like a parallel interface, the other with a tiny connector most likely is MIPI DSI as someone else suggested. That is a high speed differential interface.

[Yansi]

I don't think there is much left to discuss. If one has not enough experience designing with any kind of LCD technology, making a guesswork on a rather high end mobile phone LCD module while expecting it to have SPI interface so you can slap it on your arduino for kids, is complete nonsense. It's not gonna happen, very unlikely.

Even if it would be a display with DPI interface, having no experience designing with such stuff guarantees almost zero success here.

As was already stated, I strongly recommend anyone, if not having enough or any experience with LCDs, start with something having full documentation (and preferably also examples) available.

Start with a simple small LCD with a built in driver over SPI, then when you advance your knowledge enough, start tinkering with high speed digital stuff and the parallel data interfaces (DPI) or maybe the serial ones (LVDS/DSI). And forget arduino. That's for driving LED segment displays at best.

I am not trying to discourage anyone, just stating simple facts, also based on my own experience explaining people this stuff ain't toys for arduinos, multiple times over again and again.