TFP401A: TFP401A

Giovanni

Can you share your schematic and layout? Is the source output both audio and video? If the source is outputting both audio and video, can you turn off the audio?

Thanks

David 

yes ... I try to attach layout photos and wiring diagram ...

I'm sorry but I'm not familiar with this forum....

Hi,

You can choose to 'Insert', 'Image/Video/File', and then 'Upload' to upload the schematic/layout to this forum.

Thanks

David

Hi David, 

I apologize but I could not be able to upload the schematic other than a bunch of pictures.

The first picture displays the size of the differential pairs - to make it easier to read, they are 0.254mm and 0.768mm.

The second picture displays the distance of differential pairs from the HDMI connector to TFP401.

The last picture is the actual schematic where the TFP401 is used.

 Thanks.

Giovanni

Hi,

Do you have a EEPROM connected to the HDMI_SCL and HDMI_SDA? What video resolution are you using and does it contain audio? 

If you probe the HDMI_SCL and HDMI_SDA, are you seeing the EDID being communicated from the EERPOM to the HDMI source?

Thanks

David 

NO eeprom ..net 15-16 hdmi connector connected to 2 resistors 4K7 pull-up 5V
with oscilloscope I do not see clock on net SCL and even data on net SDA
I do not use audio ..only video resolution 640x480 60HZ

grazie

According to your experience is it possible that a wrong layout of the differential pairs RXC RX0 RX1 RX2 completely blocks the Vsync Hsync DE signals?

grazie

Hi,

Channel-0 is the channel receives blue pixel data in active display and HSYNC, VSYNC control signals in blank. But when I looked at the schematic, I don't see an issue with the connection.

If you probe the RXC, are you actually seeing the clock coming into the DFP401A? My concern is without the EEPROM, the source may not see a valid EDID and output the video. 

Thanks

David

hello david sorry for the delay in writing ... but two days ago at the end of the working day measured the current absorptions
I suspected that the card had a problem ... I had another one installed and now everything works OK.
...the TFP401 of the (first) card is faulty ...in fact the current draw is more than 100 mA lower
I asked the assembler for information and he confirmed that in the first sample they had to desolder and reposition the TFP401 because of an incorrect positioning.
Before closing the topic I have one last question to ask you:

does the datasheet recommend that the differential pair lengths must be equal to each other  ??? ....( the PCB  track length of the pair RX0 = RX1 = RX2 = RXC )

many Thanks

Giovanni