DS90C387A: Problem with columns on a display.

Marek Novak58

Part Number: DS90C387A
Other Parts Discussed in Thread: TFP401A

Hello,

I made HDMI/dual LVDS comnerter with TFP401a and DS90C387A. Also I made EDID in eeprom for fullHD resolution. Converter works but there is wierd problem with display. I have shifted image.

There are some photos of the display:

With other converter is no problem.
What do you thing about this problem?
Thanks for a reply.

over 5 years ago

0 Darryl Jeong over 5 years ago

TI__Expert 4210 points

Sounds like you are sampling on the wrong edge of the input PCLK of the DS90C387A. Change the setting on pin 20 (R_FB) to match your source. If you have R_FB=HIGH change R_FB=LOW or if you have R_FB=LOW change R_FB=HIGH

0 Marek Novak58 over 5 years ago in reply to Darryl Jeong

Prodigy 30 points

Thanks for a reply. I tried to connetc it to HIGH than LOW but nothing changed.

First I had EDID for 1024x600 I tried converter with LCD 1920x540 and everything was ok.
Then I made EDID for fullHD and the problem started.

In datasheet of the display is written that display supports two pixels per clock and the first is odd and second is even.
So I set Receiver to 2 pixel/clock, transmitter to DUAL.

0 Darryl Jeong over 5 years ago in reply to Marek Novak58

TI__Expert 4210 points

Your display and CPU output resolution should be close otherwise you will get artifacts.
The DS90C387A is just a pass thru and cannot adjust resolution/timing.

0 Marek Novak58 over 5 years ago in reply to Darryl Jeong

Prodigy 30 points

The problem was that ODD and EVEN pixels were swapped. I remade cable pinout on LVDS cable and problem disappeared.

0 Darryl Jeong over 5 years ago in reply to Marek Novak58

TI__Expert 4210 points

OK, great!

Like I said, the DS90C387A is just a pass thru.

I am going to close this item.

Interface

Interface forum

DS90C387A: Problem with columns on a display.