TMDS1204EVM: connector lanes swapped

Kevin Zheng

Part Number: TMDS1204EVM
Other Parts Discussed in Thread: TMDS1204, TDP1204

I recently purchased an TMDS1204EVM, and looking at the schematics in the User Guide, it seems the lanes are both swapped on the RX and TX connectors.

This resulted in the fan-out buffer path outputting the lane2 data instead of the TMDS clock in 1.4/2.0 mode. Can you confirm that this is an known issue and is there any work arounds? Our current development depends on the correct functionality on the fan-out buffer path. Thank you!

over 1 year ago

0 David (ASIC) Liu over 1 year ago

TI__Guru**** 161366 points

Hi,

TMDS1204 supports lane swap function as shown below when CFG1 pin is high, so this is not an issue with the EVM design.

But if you are using fan out buffer, the fan-out buffer feature will be disabled if SWAP is enabled. So you can't use the SWAP feature in your current design.

Thanks

David

0 Kevin Zheng over 1 year ago in reply to David (ASIC) Liu

Prodigy 10 points

Hi David,

the datasheet suggests that when lane swap is enabled, the fanout buffer will be disabled. So I can’t realize the scenario shown below

Kevin

0 David (ASIC) Liu over 1 year ago in reply to Kevin Zheng

TI__Guru**** 161366 points

Hi,

Your understanding is correct. The EVM was designed without using the fan-out buffer feature.

Thanks

David

0 Kevin Zheng over 1 year ago in reply to David (ASIC) Liu

Prodigy 10 points

Since SMA connectors are available on board for the fan-out buffer outputs, and AC-coupled, what was the initial intention for those? Does this mean I would need to build a custom lane swapped HDMI connector breakout boards to correctly evaluate TMDS1204's fan-out buffer feature?

+1 David (ASIC) Liu over 1 year ago in reply to Kevin Zheng

TI__Guru**** 161366 points

Hi,

I was designing one EVM that can accommodate both TDP1204 and TMDS1204. The TDP1204 and the TMDS1204 pinout are flipped from each other. With majority of HDMI2.1 application do not need the fan-out buffer, I designed the EVM to follow the TDP1204 pinout and then use the SWAP function when comes to TMDS1204.

You are correct that you will need a breakout board (https://www.wilder-tech.com/en/products/hdmi) to swap the lane back if you want to evaluate the fan-out buffer feature.

Thanks

David

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TMDS1204EVM: connector lanes swapped