TDP158: Control of HPD output

Denis

When HPDSNK_GATE_EN set to '0', HPD_SRC depends on the state of the HPD_SNK. I would recommend having a weak pulldown resistor to hold the HPD in a known state.

Thanks

David

Hi David,

I'm sorry, I made a mistake: I would like to know what happens when HPDSNK_GATE_EN set to '1'. Inside the datasheet, we can read (page 31):

HPDSNK_GATE_EN = '1' – HPD_SNK will not pass through to the HPD_SRC.

We can also read inside the datasheet:

The field set the HPD_SNK signal pass through to HPD_SRC or not and HPD_SRC whether held in the de-asserted state. 

What is "de-asserted state" for TI? Is-it open-drain like many HDMI chips?

My goal is to know if I can drive the HPD_SRC pin LOW by toggling this bit or with any other way through the I2C interface of the chip and force the HDMI transmitter to read back the EDID.

Thanks,

Denis.

Thanks David. I will do that.

Best Regards,

Denis

Denis

Also per the HDMI spec section 8.5, it is the sink that should drive a high voltage level on HPD when its EDID is ready after seeing the 5V power from the source.

Thanks

David 

Hi David,

Thanks for the clarification.

Best Regards,

Denis.