PTN3460 Flickering

[lcdguru]

First of all: A Happy New Year to all of you !

My issue is: #PTN3460 Flickering.

We are using a Baytrail Qseven module equipped with the PTN3460 for its LVDS output. A second PTN3460 is installed on our Baseboard to convert 2 eDP channels to an additional LVDS output. Everything works fine on standard TFTs (4:3 / 16:9). 

When driving 1920x540 stretched TFTs, the image flickers randomly in horizontal direction. This happens on both LVDS ports and on different 540 TFTs. On a different Qseven module, using an Analogix DPtoLVDS converter, everything works fine.

Is this a known issue / are there already workarounds?

Thanks in advance for any help / hints!

P.S.: I was trying many different timings within the TFTs parameters already.

[TomasVaverka]

Hello Andy,

Happy New Year to you, too!

Could you please let us know which PTN3460 firmware version are you using? I would recommend you to use the firmware version F6 to test to see whether flickering issue can be resolved if you have not done it yet (please use the attached PTN3460_FOA_F6.exe).

Also which Analogix part has been used in your test?

Best regards,

Tomas

[lcdguru]

Hi Tomas,

thanks for your reply, and sorry for late reaction: For any reason the notification message went into my spam directory... :-(

Answering your questions:

 - Firmware already is F6 on both parts.

 - the other Qseven module implements Analogix ANX1122I parts

Thanks & have a nice Weekend!

[TomasVaverka]

Hi Andy,

Is the configuration register (0x99) set to 0x02? If not (if it is less than 0x02), then it may have potential flickering issue.

Best regards,

Tomas

[djrs]

And one more question. Previous firmware versions did not have configuration register (0x99) to adjust PLL. What was the PLL set to for these previous firmware versions?

We are having video issues and we suspect our answer may lie here. Thanks.

[djrs]

Hi Thomas. Would you please explain why the Firmware PLL values would potentially result in flickering issues?

[lcdguru]

Hi Tomas,

thanks for your recommendation!

Currently i do not have the chance to run windows on the destination hardware, so perhaps there are any DOS- or Linux-based DPCD tools available?

Thanks & BR,

Andy

[manuelschuhbaum]

Hi Tomas,

I'm working on the same hardware and can see the issue as well.

Firmware is F6 and we have tried several settings for the Firmware PLL range, 0x02, 0x06 and 0x00. It does not affect the behaviour of the flickering.

Best regards,

Manuel

[TomasVaverka]

Hi Manuel,

Could you please provide “1920x540 stretched TFTs” panel specs for us to review?

Best regards,

Tomas

[manuelschuhbaum]

Hi Tomas,

I can see the issue on a Samsung LTI370LN01-0 panel. You can find the datasheet on the web here. Let me know if you need any other information.

Best regards,

Manuel

[TomasVaverka]

Hi Manuel,

Couple of follow-up questions:

1. Are you using one or two LVDS channel in application? Do you connect both of odd and even or only odd of PTN3460 LVDS interface to LTI370LN01-0 panel?

2. Are you using option 1 or option 2 (see below picture from LTI370LN01-0 spec)?

3. Could you please provide us with the EDID data which is used for LTI370LN01-0 LCD panel in application, so that we can check it to see whether there is any potential issue in the EDID contents?

Best regards,

Tomas

[manuelschuhbaum]

Hi Tomas,

it's a two channel LVDS application and we are using option 1, so 540 is configured as Tvd.

What format would you like to have the EDID data? Binary, Hex or a screenshot of our EDID editor with the values readable?

Best regards,

Manuel

[TomasVaverka]

Hi Manuel,

Either hex or binary file works for me.

Best regards,

Tomas

[manuelschuhbaum]

Hi Tomas,

sorry for late reply. Attached you can find a link to download the epi.bin file containing the EDID data to reproduce the flickering.

https://files.congatec.net//data/public/8033dd6147ccb84f002e9316a5628489.php?lang=en 

Best regards,

Manuel