TFT clocking behaviour?

[[email protected]]

Looking at many lcd panels it seems their interfaces boils down to:

Vertical sync
Horisontal sync
Pixel clock
R-G-B data in N number of bits.

Some use UL/DL on their "RGB" pins. I have no info on what this means.

If such screen looses data connection, but not power. Will the image remain?

And is this true for LCD, STN, DSTN, OLED aswell?

 

[Didi]

If such screen looses data connection, but not power. Will the image remain?

To my experience, no. The image fades away within a second or two.
The TFT-s seem to store the data on their gate capacitance (the latter
being just a guess based on the preceeding observation).

Looking at many lcd panels it seems their interfaces boils down to:
...

Many of the newer SVGA and up (and some smaller) use LVDS to serially
transport the signals you already saw, designing in a buffer may be a
good idea (many TFT modules have very short market life).

Some use UL/DL on their "RGB" pins. I have no info on what this means.

Neither do I. Those I used have had normal TTL voltage levels (upper
limit
being 3.3 V determined rather than 5, though). Perhaps this refers to
some upper/lower display half or something.

Dimiter

 

[Jamie]

Looking at many lcd panels it seems their interfaces boils down to:

Vertical sync
Horisontal sync
Pixel clock
R-G-B data in N number of bits.

Some use UL/DL on their "RGB" pins. I have no info on what this means.

If such screen looses data connection, but not power. Will the image remain?

And is this true for LCD, STN, DSTN, OLED aswell?

some monitors support a simple serial protocol to allow the OS to
read its firmware info so that it can identify it.

 

[Klaus Kragelund]

Hi

DL means Data Lower Display, DU means Data Upper Display

The module clock data in with the principle of interlacing like a
television. So data for line 1 is clocked in the same time as data for
line 241 (for a 640 line display)

When you stop datatransfer the display is gone immedeately (glow time
of 10-20ms)

See this datasheet for info on a common old-style display
(www.microdesign.dk/tmp/1.pdf)

Regards

Klaus

 

[Mike Harrison]

Looking at many lcd panels it seems their interfaces boils down to:

Vertical sync
Horisontal sync
Pixel clock
R-G-B data in N number of bits.

Usually Data enable as well, indicating the active region of the display. a few panels use this as a
combined h/vsync and ignore the other sync signals.

Some use UL/DL on their "RGB" pins. I have no info on what this means.

If such screen looses data connection, but not power. Will the image remain?

No, and the screen may be damaged by DC bias if left with power on and no clocks

And is this true for LCD, STN, DSTN, OLED aswell?

Mostly, yes.


There are a lot of TFT datasheets (some only connection info) linked from here :
http://support.advantech.com.tw/Cse...ea?OpenView&Start=1&Count=30&Expand=17.1#17.1