TMDS181:

Jason:

    Did you see 5v on ex_hdmi_hot_detect?

Regards

Brian

Jeevan,

What voltage does the FPGA  require from the HPD_SRC pin?

Thanks,
Zach

Hi Janson,

No, till R267 5V is noted but not after that.

Regards,

Jeevan

Hi Zach,

The HPD travels until ADV7611 and not till FPGA.

Regards,

Jeevan

Reference for ADV7611.

Hello, Jeevan,

What is the TMDS181 HPD_SNK pin connected to and is it getting 5V? Is the HPD_SRC pin connected to pin 19 of J26?

For a sink side application, HPD needs consideration. The TMDS181 drives the HPD signal to 3.3 V, which meets requirements, but if 5 V HPD signaling is required, the two circuits shown in Figure 35 are required. Please refer to Figure 35. TMDS181 in Sink Side Application (Including 5 V HPD Implementation) if the source requires 5V signaling.

Thanks,

Zach

Hi Zach

Yes HPD_SRC is connected to pin 19 of J26(FB 36 is placed now). HPD_SNK is connected to the 19th pin and 5V is noted only at one end of R267(i.e End toward the EXT_5V_Port) and whenever the HDMI port is connected, FB33 gets 5V.

Tried externally providing 3.3V to ADV's HDP pin that did not work.

In the previous design, we connected the connector J26 directly to ADV7611 and that is working fine.

Regards,

Jeevan

Jeevan,

From my understanding of your schematic, the ADV7611 supplies the HDP 5V signal. This signal is to be passed through to the HPD_SRC side and then out to the HDMI source through pin 19. If the source requires 5V signaling, the two circuits shown in Figure 35 are required. Please refer to Figure 35 of the datasheet which are not implemented in the schematic provided.

Thanks,
Zach

Zach,

According to the schematic, The connector J6 is connected to an external HDMI source (eg: PC) to receive signal. This signal is transported to TDS181 in order to be redrived and the same is sent to ADV7611. From ADV7611 the data gets converted to 24BIT Parallel data and is transported to FPGA and further to USB from where the output can be obtained.

The below given image depicts the flow of the HDMI signal.

Could you please explain what change Figure 35 makes and what it does as well? 

Regards,

Jeevan

Hello, Jeevan,

The HPD signal flows from the sink to the source. Is your sink device is sending the HPD signal?

Jeevan Sidharth G said:

Could you please explain what change Figure 35 makes and what it does as well?

The TMDS181 drives the HPD signal to 3.3 V, which meets requirements, but if 5 V HPD signaling is required, the two circuits shown in Figure 35 are required to take the signal from 3.3V to 5V. Does the source require 5V signaling or is 3.3V sufficient?

Thanks,

Zach

Hi Zach,

The Design in the pdf that I had attached in the beginning worked with FB36 being DNP. I am not able to understand how it works without the HDMI being connected to the HPD.

Regards,

Jeevan 

Hello, Jeevan,

Jeevan Sidharth G said:

The Design in the pdf that I had attached in the beginning worked with FB36 being DNP.

Could you clarify what you mean by this? I understood that you were not getting a HPD signal to the source. 

Thanks,

Zach