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LCD Data enable pin from G400-D


#1

Hi,
I am trying to activate my LCD with 800X480.
Its ER-TFT070-4 from buydisplay
I connected RGB signals in format 5:6:5 From my mainBoard (FEZRaptor) to the LCD
I tried to activate the LCD with an example from this forum.
With Scope I see all the signals (RGB, HSYNC, VSYNC) correctly

But - I dont see anything.

As mentioned, With scope I see that all signals are OK.
Except LCD_DEN. Its stable on 3.3V (or floating, I dont know).
How can I activate Data enable line on top of the HSYNC and VSYNC (or instead) ?

I have G400-D module (with FEZRaptor)


#2

I have used both a 5" TFT and 4.3" TFT from Newhaven and connected DE or DEN to the LCD_DEN output from the GHI boards.

The LCD_DEN output is programmable to be either fixed or clocked. It all depends on the LCD as some have HSYNC and VSYNC and some do not. They use the DE input to clock in the data. I recently connected a display with no H or V sync and it worked.

I could not find any timing data for your display. This will show if the LCD_DEN should be enabled or not. In FEXConfig this is the entry for Output Enable is Fixed.

One question I have is, how are you driving the backlight on this display? If you don’t do anything then it will appear black.

You may also be using the wrong timing for it although the settings for the CP7 will get you close. You’ll need to find the full datasheet for it with the timing so you can work out all the settings for the LCD controller.


#3

All the timing data seems to be in a pdf for the driver IC


#4

OK,

But How can I program the DEN to be clocked ?
I see that he is not (with a scope)

The LCD is probably waiting for the DEN. the OTA7001A is driving it.
But i have no control on the OTA7001A. Its located on a flex cable with no option to configure.
If I had contro, I could config it to use the HSYNC and the VSYNC.

I am using an example of CP7, but still no picture.
For backlight I use external power supply of 23V.

How to configure the DEN pin to work ?


#5

Use FEZConfig and change Output Enable = false and it should be clocked.


#6

Thanks for your help :slight_smile: