LVDS screens [Official Discussion]

The light source of the official 7" screen is very bright and gets very hot. Is there any way to dim it?

 

Typically on one of these diode string backlights dimming isn't simple as it involves putting a PWM signal to the driver IC's enable to adjust the duty cycle. But if heat is the only concern there are probably other things to try first because it looks like the backlight driver IC is heating up more than anything (not the backlight LEDs themselves.)

On my display at the touch overlay glass is getting hotter than 40C and about 60C at what appears to be the backlight driver IC (U2) on the adapter board, CSA02REVB. I think 40C is a bit too hot on a surface people are going to be touching. I don't know what the expected running temperature should be; but if it's running correctly I suspect just improving the cooling for the IC would be the way to go. If it's running a lot hotter than expected fixing whatever is causing that would be the ticket.

To that end is everyone seeing the high temps on the 7" display? And does anyone know what IC U2 is? I can't tell be the markings on the package.

 

It looks like some kind of Buck step down regulator and it appears to output at a little bit below 9 volts.
No idea who manufactured the IC, let alone what model it is.

Hmm... It looks like the same IC as on the UDOO board at U25 and the schematic indicates that U25 is a RT8287AZQW which is a "4A, 21V 500kHz Synchronous Step-Down Converter"

 

Nice spot atcurtis, that's a Richtek part: RT8287A and without knowing what the part/circuit is it at least fits the evidence. If you look at page 6 of the datasheet from their website, specifically the upper left diagram of "Efficiency vs. Output Current" it looks to be designed to really be putting out at least 0.5 amps to have 80% efficiency. If you look at the datasheet for the UMSH-8596MD (7" display) the typical backlight is rated to pull 0.210 amps. So that's approximately 60% efficient in the diagram for the converter. That comes out to be dissipating a watt or so and the temperature of 60C sounds about right for that.
Unfortunately not a particularly simple matter to increase the efficiency though.

 

Hi,
I Have a few questions about the LCD 15,6" Touch.
Indeed, I wonder what is the purpose of the Vin signal, which is 12 Volts , and what the 3P3V means?
Can I plug the MicroTouch directly in a USB slot?
Thank in advance.

 

I believe the issue with the 7" display heating up is actually the backlight drive current. I removed the UDOO control board from the back of the display to measure things separately and the display itself seems to get above 60C along the plastic on the back at the bottom of the display. So then I hooked the backlight directly to a SMU, set it to supply .210A per the display datasheet and found the voltage was 8.72. That was less than the approximately 8.9V from the UDOO interface board i was measuring. Then I measured the temp at the front of the display after it warmed up to be just over 30C, reasonable. So then I plugged the backlight back into the UDOO controller board with a meter in series and measured the current supplied to the backlight to be 0.277A. Seems like that extra power is heating things up.

 

Any plans for a 4.3" touchscreen? Would there be any on the market that would be compatible (like the Manga Screen)?

 

Would love to know if this one works

http://www.adafruit.com/datasheets/HSD070PWW1-B00.pdf

It's a single channel LVDS IPS screen at 1280x800. The link includes datasheet with pinouts.

 

Not sure if it will work with UDOO (drivers? connectors?) but is a very nice display.

 

Hello,

I would like to know the power consumption of the 15" touch screen.
Is is powered by the board or does it need a separate power supply ?

Thanks in advance.
MG.

 

Hello, I hope someone can help.

OK, so I have followed the procedure from the website to load the LVDS 15.6 inch touch screen that I purchased.

Downloaded both SD images for Ubuntu & Android.

1) I loaded linux first, and applied the kernel update as suggested in procedure.
2) No issues and touch screen working fine under linux ... Yay!
3) shut down the system
4) I swapped out the linux SD for the android SD
5) I then reset the env variable to support 15 Inch for Android using the following command from the procedure:

setenv bootargs console=ttymxc1,115200 init=/init video=mxcfb0:dev=ldb,1366x768M@60,if=RGB24,bpp=32 video=mxcfb1ff video=mxcfb2ff fbmem=28M vmalloc=400M androidboot.console=ttymxc1 androidboot.hardware=freescale mem=1024M

saveenv

boot

After booting to Android, the OS is fully operational, but the touch screen is not recognizing touch-input.

So, since "touch" WAS working and verified on Linux, I can infer that it's not the monitor itself and that I have the 2 USB and LVDS connections connected to UDOO correctly.

Any ideas what might be the issue with "no-touch" on Android? I've opened a ticket as well.

Thank All

 

All ... I received a response from Uduu support on the above issue.

This is a "known issue" with the 15.6 inch touch monitor and the current version of Android.

They are working on it, and it will be fixed with the next release of the Android OS for Udoo.

I guess that I'll have to wait, but I think they should update one of a number of locations to warn potential buyers that the 15.6 inch touch screen is currently not fully supported under Android. The tutorial video makes no mention of it while showing Android working on 7 inch and 15 in (Linux).

I have responded and asked when the next release of Android will be. Since my Project is creating a Kiosk for Medical offices, which requires Android due to the software that I'm using to lock down & secure the Kiosk from a HIPAA compliance perspective, I am "on hold" until this issue is resolved.

More to follow ...

 

Hey all,

I'm new to just about everything related to UDOO and this type of 'making'. I have just received my Quad with both sizes of touch screens and am trying out both Ubuntu and Android. I have two SD cards for that purpose. So far I have tried the 7" with Android and it seems to work fine. I am now trying Ubuntu, but it seems that the screen is wonky. I do have bars at the top and bottom (I'm not sure what they are called in Ubuntu land, but the top has the applications menu, etc. while the bottom shows the desktops, your current location, etc.).

However the stuff in between the bars seems cut off at the bottom. For example, on the desktop, the bottom icon, for the trash, was barely visible above the bottom bar and I'm fairly certain the icon itself is taller than the bar - meaning that the icon likely extended back behind the bottom bar and beyond the bottom of the screen. I was able to just snag it and move it to a more visible position, but that wasn't the only sign there is an issue.

From the top menu, I went into Applications and browsed the menu tree to System Settings. Scrolling down to the bottom, I cannot see the items under the 'System' section except the top few pixels. I tried minimizing and maximizing the window to no effect. I thought maybe the screen resolution was wrong, but with the top and bottom bars properly placed, I don't see how that could be.

I'm such a newb that I don't know how to take screenshots using the touchscreen otherwise I'd have pasted a picture to show what I'm talking about.

Any ideas?

Edit - I tried activating the onscreen keyboard in the accessibility settings but it doesn't seem to work.
Edit 2 - Same accessibility keyboard issue on the 15.6" touchscreen. It just doesn't show up.

 

Hello Delba,

Thanks for the datasheet,
But i think my TS 15.6 '' that I have bought on your udoo website is an innolux g156bge. Am I wrong?
Regards.

 

Hello,
I got my board + the 15" touch screen.
I can get the display on the screen but the touch is not working at all.
This is my configuration:
- Udoo quad
- The 15" touch screen
- Linaro Ubuntu 12.04 LTS

I followed the lvds display tutorial but when launching calibration tool, I get the following message:
Error : No calibratable devices found.

When I run a dmesg, I can find the following lines:

[ 2.028945] usbcore: registered new interface driver usbtouchscreen
[ 2.035600] Sitronix touch driver 2.9.1
[ 2.039454] Release date: 20120507
[ 2.043226] sitronix_reset_ic
[ 2.166411] send status reg command error (-5)
[ 2.170878] sitronix: probe of 2-0055 failed with error -5

So, the touch driver seems to net being properly started.

Did someone faced this issue ?
Thanks.
MG

 

Hello, I am using the 15.6 inch touch screen monitor with a quad. I was finally able to boot the new 4.3 Android this morning and the touch screen is recognizing touch input. However, the "orientation" of the touch input is 90 degrees off. For example, if I want to scroll left and right, I have to swipe up and down. If I want to access the menu controls at the "bottom" of the screen, I have to click somewhere along the right edge of the screen. So, the orientation of the touch sensors seem to be off by a full 90 degrees.

Is anyone else experiencing this? IF so, what is the resolution?

Please advise! Thanks.

 

@jwilgus

It doesn't look like anyone who can help us looks at the forums. I haven't seen your problem. Sorry.

 

Hello,

i have bought the UMSH-8596MD-20T. Now i must make the Cable. I have the Interface pin Layout from the UMSH-8596MD-20T and i know that at http://udoo.org/download/files/schemati ... matics.pdf on site 11 i should find what i should know, but i have a Problem.

Where exactly must i add the pins? Please help me a little bit and tell me for example where i must add from UMSH-8596MD-20T ; PIN 13 - 15 (Blue) to the schematics.pdf.

Is it possible that you show me the schematics of your cable ?

Have a nice day