TMDS181: Lane swap problem

Toshi

Expert 1780 points

Part Number: TMDS181

Hi, TI,

I detected a problem under LANE swap mode.

Under default setting, Set the SWAP_POL=L ,

Input a 1080P60 signal , sometime the device is unstable as below,

I texted on TMDS181EVM, Do you have any Idea to solve the problem ?

I guess the problem was occured under retimer mode,

The problem was not occured inder signal detect = ON and redriver mode.

over 8 years ago

0 Moises Garcia over 8 years ago

TI__Mastermind 23815 points

Hi Toshi,

Could you elaborate what is the problem when SWAP_POL=LOW?
for debugging set SIG_EN=LOW
lane swap works in redriver and retimer mode.

Regards

0 Toshi over 8 years ago in reply to Moises Garcia

Expert 1780 points

Moises, thanks. I'll send pictures to you via private message.

0 Moises Garcia over 8 years ago in reply to Toshi

TI__Mastermind 23815 points

Hi Toshi,

Do you hvae the same behavior when SWAP/POL is left NC?
Could you try adding a 1uF capacitor on SWAP/POL pin?

Regards

0 JMMN over 8 years ago in reply to Moises Garcia

TI__Guru 60870 points

The capacitor on SWAP/POL should be 0.1 uF to reduce effect of noise on the unconnected pin. Is the input lane and polarity swapped or just lane swapped?

0 JMMN over 8 years ago in reply to JMMN

TI__Guru 60870 points

Clarification, by "unconnected pin" I meant a pin that is being configured at the mid-level.

0 Toshi over 8 years ago in reply to JMMN

Expert 1780 points

I want to swap just lane. So I've set the Pin as SWAP_POL=L .
When WAP/POL is left NC, The device(TMDS181EVM) works fine without swap

0 Moises Garcia over 8 years ago in reply to Toshi

TI__Mastermind 23815 points

Hi Toshi,

Lane swap feature is used when from layout the input lanes are swapped, it will reorder the lanes as depicted in datasheets figure 26 and table 2.
TMDS_CLK will move to IN_D2, now these pins will be used for clock recovery.

Regards

0 Toshi over 8 years ago in reply to Moises Garcia

Expert 1780 points

Moises, thanks.
The problem was cleared.

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TMDS181: Lane swap problem