TUSB1064: Change EQ setting by I2C

Hi,

Devyn Lee said:

We are trying to change DP EQ setting by I2C,  it works, but I found it seems that we have to plug out then plug in the USB-C to make it work.

How are you evaluating if the chnage in EQ works or not?

The TUSB1064 should be able to alter EQ without requiring a hotplug. 

Hi,

In our certain test environments, high EQ triggers bit errors that result in no image output, requiring the EQ to be lowered. For this scenario, if the TUSB1064 is initially set to high EQ, such as 9, then connecting it to a source (laptop) and then adjusting the EQ to 2 via I2C still yields no image. However, if the EQ is first reduced to 2 via I2C prior to connecting the laptop, or change to 2 then hotplug, the image displays normally.

Hmm, odd.

I will test this in lab and get back to you. Please provide me 1-2 days to get this setup running for testing. 

sure, thanks for your support.

No problem. I'm still working on the setup, resources in our lab are shared, so I will send an update as soon as I have information available. 

Hi, 

A kind reminder 

Hi Devyn,

We had a national holiday in the US and I was out of office. Apologies for the delay. I will have an update soon.

Hi,

I was not able to test the TUSB1064 in lab as our board is only operation over I2C (It's an older version of the TUSB1064 EVM available for purchase)

I was able to do testing on the TUSB1046, TUSb1146, and the TUSB5461-Q1 all of which do update the EQ "live" as the signal is passing through.

Can you confirm that register 0x0A is configured correctly?

Hi:

Yes, I have double checked with register 0x0A, it did be configured to be 0x13 or 0x17, I think it should be ok, right?

I tried the FLIPSEL bit, when I switch 0x0A from 0x13 to 0x17, it can take effect immediately. But for DPEQ register 0x10 and 0x11. when I configured it to be 0x2222, I can read via I2C, it is correct, but the signals seems to be not change. Only take effect after I re-plug as what I said above.

Do you have snooping enabled or disabled?

I ordered a fresh set of TUAB1064 EVMs for testing. I will test on those once they arrive. 

Hi

We didn't configurated snooping, and I have double checked with register 0x13, it is the default - 0x00, so the snooping is enable.

And I have try to configurate snooping today, after I disable it, I found the EQ setting work immediately.

So I want to check with you, will it be any problem if I disable AUX snoop?

Sorry, I should made a mistake. After I repeat testing, I found the aux snoop seems not affect EQ setting, I am not sure what happen, now even I configured 0x13 back to 0x00, after I change the EQ setting, new EQ works. I will found other unit to double check.

Besides, re aux snoop, I found it ialso affects display, so I still would like to check with you, if I disable it, is there any problem? I found when GPIO mode, the function is disable, what's the benefit if I enable it.

Hi,

Devyn Lee said:

Sorry, I should made a mistake. After I repeat testing, I found the aux snoop seems not affect EQ setting, I am not sure what happen, now even I configured 0x13 back to 0x00, after I change the EQ setting, new EQ works. I will found other unit to double check.

Let me know if this is reproducible.

Devyn Lee said:

Besides, re aux snoop, I found it ialso affects display, so I still would like to check with you, if I disable it, is there any problem? I found when GPIO mode, the function is disable, what's the benefit if I enable it.

AUX snooping allows for the TUSB1064 to allow some of its registers to be changed based off of the AUX. The AUX channel is how the DP source and DP sink communicate, so using AUX snooping should allow for a more robust and adaptive system. Especially in terms of power savings as AUX snooping allows for unused lanes to be turned off.