TMDS1204: GBL_SLEW_CTRL time step

Hayashi-san

Can you please share the compliance test report? 

You should see the slew rate change as soon as you write to the I2C register. But slew rate will only take effect if you configure the TMDS1204 in limited mode.

For DC-coupled output, the TX_AC_EN needs to be set to 'low'.

Thanks

David

Hi David

I attach on it.2514.HDMI.pdf

Please answer to my question?

Hideki Hayashi1 said:

The questions is that, how long does the GBL_SLEW_CTRL register expect to change by 1 step? 

Customer and I knew this and set to limited mode.

David (ASIC) Liu said:

But slew rate will only take effect if you configure the TMDS1204 in limited mode.

Customer and I know this. Customer today tries to change the setting to measure again. But please teach us about GBL_SLEW_CTRL register's theoretical (or practical) value by 1 step increment? 

David (ASIC) Liu said:

For DC-coupled output, the TX_AC_EN needs to be set to 'low'.

Best regards,

Hayashi

Hayashi-san

Are you asking how much the edge rate will change with each step? If this is the case, please give me one day and let me collect this data on the EVM. 

Meanwhile, can you please share the customer schematic for review?

Thanks

David

Hayashi-san

Below is the rise and fall time I took on the EVM. Trial 1 is the slowest edge (0) and Trial 8 is the fastest edge (7).

From their report, their rise time is too fast. Have they tried to change the setting to slow down the edge rate?

Thanks

David