LCD To LCD adding a VGA out - Page 1
Forum section: electronics / projects

author: sampler1
author_rank: Regular Contributor
timestamp: October 13, 2020, 07:35:14 pm
content: Hi,I have a device that has a 5.7" MG3224C3-SBF - LCD Screen Display Panel 320*240. The information on the Graphic display is just too crowded, also these displays fail often.My objective is to produce a small PCB that has an input 14 pin Ribbon connector to pass the signal through to the 5.7" LCD display ( easy enough ) then have a circuit that can produce a VGA output so a larger monitor can be connected. It would convert the LCD signal to a VGA output. I hope this is clear.This type of electronics is really out of my field.I would like to know what constructive opinions you might have. OR maybe someone might be knowledgeable enough to work on a design for me at a reasonable $$.Best regards to all,PS: does a LCD to VGA circuit exist?

author: m k
author_rank: Super Contributor
timestamp: October 14, 2020, 12:27:16 pm
content: LCD as a connection standard is a bit hazy.Is it possible that the surrounding machine has a composite video output somewhere?

author: james_s
author_rank: Super Contributor
timestamp: October 14, 2020, 07:16:17 pm
content: There are many different interfaces. If the LCD is the sort with a digital RGB H/V/dotclock interface then what you want to do is fairly easy, although you will probably need a scan doubler depending on refresh rates. This is something that can be done with a small FPGA.*Edit: I found a datasheet for the display, it doesn't have the sort of interface I was thinking of, but it looks like it is quite primitive. It should still be relatively simple to use an FPGA to create a framebuffer that can emulate that display.

author: sampler1
author_rank: Regular Contributor
timestamp: October 14, 2020, 07:17:41 pm
content: The Machine is a digital audio mixer. Tascam DM-3200. It only has the 5.7" MG3224C3-SBF - LCD Screen Display Panel 320*240. The connection to the display is a 14 pin ribbon cable. I have tried to find a data sheet for this display but up to now I cannot.What I did find is a guy in France selling the exact thing I want to build but it is for sure he is not sharing as he is charging an outrageous price. I am quite sure only his two light green PCB are custom made and the dark PCB is store bought.Maybe someone in this forum knows what the dark PCB is?Ill post the photo here.

author: james_s
author_rank: Super Contributor
timestamp: October 14, 2020, 07:21:13 pm
content: This is the datasheet I found. It's sparse but it gives you the basics.That picture you found looks like a microcontroller, just a wild assed guess it's some kind of ARM based chip. It's probably reading in the LCD data and creating a VGA signal to display it. The smaller IC is likely just a buffer or level shifter.

author: sampler1
author_rank: Regular Contributor
timestamp: October 14, 2020, 07:31:38 pm
content: James,Thanks for the Data sheet!Would you happen to know anyone who might be interested in designing something for me? or maybe point me in a direction that I might find someone?I am located in Canada.Best regards.

author: james_s
author_rank: Super Contributor
timestamp: October 14, 2020, 09:18:57 pm
content: I don't, but how much does the already available option cost? Hiring someone to develop something for you could easily cost a few thousand dollars, it's at least several dozen hours of work. Unless there is enough market for these things to compete with the person who is already selling something I don't see how it's going to be worth it. If you wanted to develop something yourself it could be a fun project but it sounds like you are a ways away from being able to do that currently.

author: sampler1
author_rank: Regular Contributor
timestamp: October 15, 2020, 03:40:24 am
content: My mama always told me there will be a many people with a thousand reasons why you should not do something but i never listenedyour advise on doing it myself might be exactly the way to go.Tonight I already found out what components its based on might not be as hard as it looks. Parallax Propeller P8X32A MicrocontrollerBest regards!

author: james_s
author_rank: Super Contributor
timestamp: October 15, 2020, 04:18:45 am
content: That makes sense, those are multi-core processors as I recall, I've never worked with one before. I would bet he's using one core to generate the VGA signal and another core to read the signal from the LCD interface but that might not be necessary. I would use a small FPGA if I were going to attempt something like this, but a fast enough microcontroller ought to do it too.

author: m k
author_rank: Super Contributor
timestamp: October 15, 2020, 08:38:32 am
content: CXD1178Q and the likes seems to be get it before it's gone.

author: Zero999
author_rank: Super Contributor
timestamp: October 15, 2020, 12:15:30 pm
content: Quote from: sampler1 on October 13, 2020, 07:35:14 pmJust one question: why? The device has a crappy resolution of only 320*240, so how will scaling it up so a larger screen help? You'll still get the same level detail, just spread over a larger area. The only reasons I can think of is if the user has poor eyesight, or they want to view the screen from a long distance.

author: sampler1
author_rank: Regular Contributor
timestamp: October 16, 2020, 04:32:02 am
content: why???The Tascam DM-3200 features 32 full-featured channels and 16 returns for a total of 48 channels at mixdown. If you have ever mixed 42 channels you want to see things fast and clear..Maybe you never heard this but size matters..5.7" verses a big one makes a huge difference. VGA that is ..Have a great day guys and stay safe <https://www.parallax.com/sites/default/files/downloads/P8X32A-Propeller-Datasheet-v1.4.0_0.pdfSee pg.12

author: BrianHG
author_rank: Super Contributor
timestamp: October 16, 2020, 06:41:59 am
content: I'm sorry, but my entry price to perform such a job would be 15K$ CAD.Though I do guarantee proper functionality.

author: eblc1388
author_rank: Frequent Contributor
timestamp: October 16, 2020, 07:09:13 am
content: Quote from: sampler1 on October 14, 2020, 07:17:41 pmCome on man, 210 euro or US$246 for a such a niche product seems very reasonable to me, hardly an outrageous price.

author: Zero999
author_rank: Super Contributor
timestamp: October 16, 2020, 07:29:08 am
content: Quote from: sampler1 on October 16, 2020, 04:32:02 amIf the device supports a higher resolution than 320*240, then great, otherwise I see little benifit in increasing the display size, unless you do some clever AI upscaling.

author: ebastler
author_rank: Super Contributor
timestamp: October 16, 2020, 10:55:32 am
content: Quote from: sampler1 on October 16, 2020, 04:32:02 amUnless you have problems with your eyesight, I agree with what others have said: I don't see the benefit. A 5.7" display with 240*320 resolution has 70 DPI, or pixels which are 0.36mm wide. What would you gain by blowing them up to, say, twice the pixel size?You do realize that, while you monitor would be capable of showing 640*480 in VGA mode, you will still only be feeding it image information on a coarse 320*240 grid, right?On the other hand, if you really want the VGA output, and want it for a single unit only: Go buy that French adapter! (Unless you are extremely bored and have a few weeks of spare time to burn...)

author: m k
author_rank: Super Contributor
timestamp: October 16, 2020, 08:12:35 pm
content: I think it can be even worse.For example if picture has waves the bigger screen is not going to smooth them in any way.Code:** **** * * ***** * ****Square pixel can be smoothed with antialiasing and so, even non pixel corners will be smoother but line thickness will remain.Same goes with letters.The case is different if machine is outputting something else and screen is extrapolating that information.Interpolation of an unknown shape is still quite a practical impossibility.

author: james_s
author_rank: Super Contributor
timestamp: October 16, 2020, 08:21:50 pm
content: Quote from: eblc1388 on October 16, 2020, 07:09:13 amThat does seem quite reasonable, certainly I couldn't build a competing device and sell it for less. If it was something I needed I might try to build something myself because it's fun but even valuing my time at zero it's probably $100 worth of parts and materials by the time I pay shipping on a couple different orders, and then several tens of hours of development time. If my goal was to earn money I'd be much better off taking a second job working the counter at the local McDonalds for minimum wage.

author: BrianHG
author_rank: Super Contributor
timestamp: October 16, 2020, 08:41:43 pm
content: Quote from: m k on October 16, 2020, 08:12:35 pmEdge and line thickness interpretation can be done. 45 degree angle lines can be extrapolated.320x240 x (2x2) (IE 4x) to 640x480 (VGA), there are still problems with getting a nice interpreted 45 degree angle lines.320x240 x (3x3) (IE 9x) to 960x720, or larger 1280,960, you can get very nice interpreted 45 degree angle lines.

author: BrianHG
author_rank: Super Contributor
timestamp: October 16, 2020, 09:04:04 pm
content: One thing the OP hasn't mentioned is if the image needs to be rotated 90 degrees. The device he may be enlarging may be in portrait mode.This means the 640x480 VGA will have a 240x320 image on it with black borders, unless he it willing to rotate the output VGA monitor.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 17, 2020, 03:40:41 am
content: Quote from: sampler1 on October 16, 2020, 04:32:02 amWhy ? the lcd screen is coded in the chip / cpu whos driving the lcd, even if you put an 48 inch monitor you wont get more displayed channels, it is coded that way, you have to reverse coding to rewrite the displayed stuff on the main processor ....bad reasoningattached is the coloumn driver ic NT7702 of the MG3224C3-SBF - LCD Screenand yes you have already a solutionhttps://www.2seemy.com/you find it too pricey but eh do you want to takes chances on an undevelopped product, having problems, creating problems, damage your tascam ?You surely did a search on the tascam forums ??https://www.tascamforums.com/threads/dm-3200-screen-on-computer-via-usb.3437/https://www.tascamforums.com/threads/2seemy-owers-users.5889/

author: m k
author_rank: Super Contributor
timestamp: October 17, 2020, 10:32:07 am
content: Quote from: BrianHG on October 16, 2020, 08:41:43 pmNot connected shapes are easy of course.It's like a magic wand of image processing sofware, sometimes you just wonder how wrong those waypoints can be.Anyway,I'd make it a wireless Miracast.Problem seems to be that other stuff are too cheap, it gives wrong impressions.Normal thing, finally price goes up if demand remains.