NHD-7.0-800480EF-ATXL#-CTP dead?

[vserov]

Just received this LCD from mouser. According to Datasheet it has the same pinout, voltage and timings as NHD-5.0-800480TF-ATXL#-CTP. When I connect this LCD to controller that works with 5" LCD - I see white backlight with vertical lines on it.
Can you suggest something?
Thanks.

[Michael_L]

Are you using our controller board with the SSD1963 controller?  If so, try changing the first parameter after the hex B0 command from hex 0C to hex 08.
If not using our controller, try finding the command in whatever controller you are using that controls whether the pixel data is latched at the rising or falling edge of the pixel clock and changing it.  Let me know if this works for you!

[vserov]

I have my own controller. I tried to change parameter in my module "pixelclk-active <1>" to "pixelclk-active <0>". No change.
Can you confirm that it is the same pinout and timings as 5 inch LCD?

[Michael_L]

Yes, the pinout and timing is the same between the two displays.  I don't know if that setting you changed on the controller is effectively changing the pixel clock to falling edge triggered or not, but that is the only "difference" there is.    They use the same driver ICs.  Even so, the "polarity" of the pixel clock edge triggering should still allow for the display to operate, just may have colors/images that are undesirable if not set correctly.

It seems like the display is not getting initialized.  Either your MCU/controller is not communicating with it correctly, or maybe your initial hardware reset is not properly taking place.
It's also possible there is something wrong with the connection.   Lastly, if you have accidentally shorted certain pins on the display it is possible it may be dead.

If you are certain your controller is configured correctly, and all connections are correct and secure, you may email us at nhtech@newhavendisplay.com to set-up an RMA so you can return the display to us for analysis.

[vserov]

Just tried another LCD - the same result. So it is something with init sequence or some difference that I missing. My controller works perfect with NHD-5.0-800480TF-ATXL#-CTP
My question is - what the role of DEN signal? I grounded it in NHD-5.0-800480TF-ATXL#-CTP and also here.
And in the power sequence diagram you mention signals: AVDD, RSTB, STBYB, VSD. I can't find them at the LCD connector. What is important in power sequence?

[Michael_L]

Ah yes, the default settings between the 5" and 7" displays are in fact different.  This is why your controller is working fine with the 5" and not the 7".  The 5" display does not use the DEN signal, whereas the 7" does.  If you would like to change this, you may create a short (usually with a 0 ohm resistor) across pads R4 on the FPC cable of the 7" display.  This will eliminate the need for the DEN signal, and the display will perform like the 5" TFT. 

[mogtaba]

Hi Michael_L
i have been following your post, i have the same problem.
i tried the above suggestion but didnt work for me
i need to  create a short (usually with a 0 ohm resistor) across pads R4 on the FPC cable of the 7" display, but cat find the R4 its not labelled.
thanks in advance.

[Michael_L]

Please see below image for R4's location.

[attachment deleted by admin]

[vserov]

I confirm that it works with using DEN and inverting pixel clock.
I didn't touch R4. I just provided signal DEN from CPU.
Thank you.

[mogtaba]

HI
I have tried the two options, option one (shorting R4 with zero ohm ) and running my same 5" display code. and option two enabling the DEN as attached in the image ( the yellow Channel is DEN and the blue is one of the data line) (as you can see its as the data-sheet said)
and unfortunate all what i got in the 7" display is just a white screen.
P.S if i connect my 5" it works fine.
plz help   .
Mojtaba

[attachment deleted by admin]

[mogtaba]

Kindly, , ,
any one can help me here. . . ??

[Michael_L]

Have you tried what vserov has tried with inverting the pixel clock too?  It is possible the display has either been damaged or is defective, do you have another to try?.

[mogtaba]

yes i did, i have another lcd with the same result.
iam using am3354 processor
and also i tried changing PLL (133.33MHz to 300 MHz) and PCLK (9.5MHz - 30MHz).
is there way for debugging.

[vserov]

Inverting pixel clock affects only picture quality. You should see the picture anyway. Try to check your DEN signal. It should conform the datasheet.

[mogtaba]

Hi all
is there any update to this issue (compatibility  NHD-7.0-800480 & NHD-5.0-800480).
thanks