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Original question:

SN65DP159: No MAIN LINK TMDS Outputs

SN65DP159: mostly no TMDS Output

Roland Hanslick
Prodigy 20 points
Part Number: SN65DP159

Hi, we use a board from inrevium with the SN65DP159RSB on it. We have heavy problems to get out a HDMI Signal. The strange Situation is, that we have output to a monitor only with ONE Type of a 5 m, not high quality cable. We tested a lot of cables, different sizes, high quality, short down to 75cm and Different monitors. Also a HDMI Splitter in between. Sometimes we get a output to a monitor with other cables than the "good working one" through the splitter, but than we see failure pixels on the monitor. We tried some changes on the registers. Somtime enable 75 to 150 Ohm brings a solution with splitter, but than without splitter no signal. If we use ALL of the cables and the splitters in variations with a notebook HDMI output, all is working well. We want to connect later on a  2880x 1440 VR. We have in summary 5 Systems build. On one of them the VR is running. we search many day till now without success. Now here i hear about a second page of Registers enable with 0xff to 0x01. Are there more possibilities on the second page to try out, or have you a additional idea what we can do.

May thanks.

  • 0
    TI__Guru**** 177926 points

    Roland

    1. For applications where the GPU or Sink does not support clock stretching the DDC lines from the GPU/DP TX should bypass the SCL_SRC and SDA_SRC but still connect to the SCL_SNK and SDA_SNK pins on the DP159. The SCL_SRC and SDA_SRC pins must be pulled to ground. Note that if the GPU/DP TX cannot support the 5V DDC lines from the connector, a level shifter is needed to step down the 5V signals to the voltage level the GPU/DP TX can support.

    2. Please check the input clock waveform, replace C7 and C8 with 0 ohm resistor, and check the input clock waveform again.

    3. Please check the power-up timing between VCC, VDD, and OE, and make sure it meets the timing requirement in Fig 22.

    4. How is the HPD from the HDMI connector being connected to the HPD_SNK of the DP159?

    5. TERM_SEL needs to be set to 00(No termination), or 01(150 to 300-Ω) for HDMI1.4 or 11(75 to 150-Ω) for HDMI2.0.

    6. Please download the EyeScan Tool and use the tool to plot the input eye diagram. The tool is available here: http://www.ti.com/product/SN65DP159/toolssoftware.

    7. Please also use the tool to dump out both Register 0 and Register 1.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    TI__Guru*** 146695 points

    Roland:

       Any update?

  • 0 in reply to Brian Zhou
    Prodigy 20 points

    Hi Brian,

    we had two Systems with the same Problem. We played with Registers without success. At the last we replaced the HDMI Cards with new ones and now it works WITHOUT writing any Register!

    From our side, we have no idear, what is really demaged and WHY. If we have time we try to exchange the D159 on a demaged board to find out, is it only that IC. With the EyeScan Tool we could´n work because this neesds a Special Hardware we don´t have.
    Thanks for your Support and if you have any idea what could be destroy the board except ESD, or if it could be another reasson for theat issue, let us now.