TMDS181RGZEVM: device stops operating at power cycle

Lenio Cacula

Genius 16770 points

Part Number: TMDS181RGZEVM
Other Parts Discussed in Thread: TMDS181

The setup runs 4K video:

DP source -> DP-HDMI Adaptor -> 181 Eval -> HDMI Sink MNA

The system runs correctly from power up.

Here are the details of the failure

When we cycle power to the 181 Eval the video blanks and will not recover
We get an IIC error of TMDS_Scrambler_Status = N
When we disconnect and reconnect the HDMI source cable to the 181 Eval, it starts working
Same failure mode with DP-HDMI Adaptors from other vendors
Failure also happens when we cycle power to the 181 Eval and the HDMI Sink MNA
Failure does not happen when we remove the 181 Eval from the system and just cycle power to HDMI Sink MNA
Failure does not happen when we replace the HDMI Sink MNA with a 4K monitor
Failure does not happen when we remove the DP-HDMI Adaptor and have a HDMI source

Here are the jumper setting on the Eval board:

J1 2-3

J6 1-2

J4 1-2

J3 open

J12 open

J11 open

J17 open

J15 open

J7 open

J8 1-2

J14 open

Any suggestions to debug the issue?

Thank you!

over 5 years ago

0 David (ASIC) Liu over 5 years ago

TI__Guru**** 179526 points

Hi,

Can you populate R131, de-populate R129 and R130 and see if the issue can be resolved?

Is this HDMI1.4 or 2.0?

Thanks

David

0 Lenio Cacula over 5 years ago in reply to David (ASIC) Liu

TI__Genius 16770 points

Hi David,

I will find out about the specific standard.

Can you please elaborate on what is accomplished by making the suggested mods?

Thank you!

0 Lenio Cacula over 5 years ago in reply to Lenio Cacula

TI__Genius 16770 points

David,

I confirmed that the tests were run with HDMI 2.0 4K 60 4:4:4

Thank you!

0 David (ASIC) Liu over 5 years ago in reply to Lenio Cacula

TI__Guru**** 179526 points

HI,

Are they able to get the monitor to work with the EVM modification?

The 5V provided by the source goes straight to the monitor and will not turn off when the TMDS181 EVM is being powered cycled.

If R131 is not populated and R129 and R130 are populated, then HPD goes straight from the sink to the source and will not go low when the TMDS181 EVM is being power cycled.

So both the source and the sink do not know the TMDS181 EVM is being powered cycled and retain their initial HDMI2.0 state while TMDS181 drops down to HDMI1.4 state after being powered cycled.

With the board modification, the HPD will go low and and then high, and this will force the source to read the monitor SCDC registers again and in turn configure the TMDS181 back to HDMI2.0 state base on the DDC snoop

Thanks

David

0 Lenio Cacula over 5 years ago in reply to David (ASIC) Liu

TI__Genius 16770 points

David,

the EVM was originally configured with R131, and without R129 & R130.

The snoop configuration prevents the board from working altogether. Does that provide any useful information for us to come up with more options to solve the issue?

Thank you!

0 David (ASIC) Liu over 5 years ago in reply to Lenio Cacula

TI__Guru**** 179526 points

Lenio

Did they change the J1 jumper from 1 and 2 to 2 and 3?

Thanks

David

0 Lenio Cacula over 5 years ago in reply to David (ASIC) Liu

TI__Genius 16770 points

The discussion has continued in private.

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TMDS181RGZEVM: device stops operating at power cycle