TMDS1204: TMDS HPD_IN and HPD_OUT in sink application

Adding point .. I am using TMDS1204 in SINK path

Hey Venkatesh,

Would this be a correct block diagram for your system?

venkatesh ponduri said:

1. Is there any relation between HPD_IN and I2C bus to be active?

For DDC communication to take place between a source and sink HPD must be set high at the source. 

venkatesh ponduri said:

2. In sink application, HPD_signa is output from SoC. So What is exact HPD_IN and HPD_OUT connection if I use TMDS1204 as sink application? I believe HPD_IN should drive by SoC and HPD_OUT should connect to HDMI RX connector.

In a sink application HPD_IN should be the 5V HPD coming from the panel, and HPD out should be going to receptacle.

Let me know if you need more clarification.

Best,

Vishesh Pithadiya

Here is a reference schematic. I will have a look at the one you sent and get back to you shortly.

Hi Vishesh,

Thanks for response.

1. I am not talking about DDC I2C. We have other I2C to program internal registers that one. That pin-21 and 22. Is there any relation between HPD_IN and normal I2C?

2. You mentioned Panel in your block diagram. Panel means SOC/processor?

3.In Sink application usually HPD should be output from SoC right. means SoC should drive this signal to outside world right. FYI Below is my block diagram

Thanks,

Venkatesh

Also there is not difference between HPD_IN and HPD_OUT connections in both source and sink application circuit given in Datasheet. Can you pls check once. Below is image captured side by side.

From application circuit, both case HPD_OUT connected to SoC/FPGA means HPD signal is always input in both Tx and Rx application.  But this is not the case i believe. 

In Tx application, HPD signal is input 

In Rx application, HPD signal is output.

pls check the HPD_IN and HPD_OUT connections in SINK application once