Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Stratix3 Dev Kit, HSMC Card Issue

Hi,

I'm developing a video processing app on a Stratix3 dev kit. I've been experiencing cross-talking issue of the HSMC Debug Header Breakout Board that come as part of my kit.

The input signal is digitized RGB (10bits for each channel) with VSYNC, HSYNC and CLK. These signals are generated by TI's TVP7002EVM. To be specific, the pins I use are test points of RGB output, DCLK, VS, and HS on the TVP7002 board. Info of TI's board can be found here: http://focus.ti.com/docs/toolsw/folders/print/tvp7002evm.html

and user's handbook: http://focus.ti.com/lit/ug/sleu098/sleu098.pdf

The video signals are fed into the HSMC daughter card I mentioned above.

I use jumper wires connection between the two ends. The wire's DigiKey part number is: H2BBT-10106-B4-ND.

If I connect only the DCLK, VS, and HS, signals traces I extracted from SignalTap II are perfectly clean. However, when any color data pin is connected, the SYNC signals are destroyed by false pulse. I attached the project folder of my connection test. It has the exact pin assignments as my video processing project does.

At this point, I do not have a clear clue of the problem source. Is this due to electrical property of the HSMC daughter card or some thing is wrong with my design?

Best regards,

5 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    TVP7002 has a single ended interface, reliable operation surely depends on a good ground connection. For this reason, the data header on the eval board provides individual ground pins for each data line. How many ground lines did you use and where did you connect them at the breakout board?

    I only have a schematic of the HSMC debug header, I see no ground pin on the data header, just two ground test pins for the complete board. Looks like the debug board isn't intended for single ended interfaces at all.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    --- Quote Start ---

    TVP7002 has a single ended interface, reliable operation surely depends on a good ground connection. For this reason, the data header on the eval board provides individual ground pins for each data line. How many ground lines did you use and where did you connect them at the breakout board?

    I only have a schematic of the HSMC debug header, I see no ground pin on the data header, just two ground test pins for the complete board. Looks like the debug board isn't intended for single ended interfaces at all.

    --- Quote End ---

    Hi, Fvm,

    Thank you very much for your reply.

    I have the same problem in another test configuration. I use a small conversion board between TVP 7002 and the debug board, on which all data ground are connected together via a ground trace and this trace is connected to one of the two test ground pins of debug board.

    So from your suggestion, the best solution is to use another type of HSMC debug header that have ground pin for each input data pin?
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Yes, something of this kind. Please consider, that the HSMC connector has a low impedance ground at the center while the debug header has none. This can work with differential signal pairs but is really bad with single ended signals.

    If the debug header allows to solder a number of additional ground pins with low impedance connection to the HSMC ground node, this may work as well. Otherwise you should think about designing your own interconnect board.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    --- Quote Start ---

    Yes, something of this kind. Please consider, that the HSMC connector has a low impedance ground at the center while the debug header has none. This can work with differential signal pairs but is really bad with single ended signals.

    If the debug header allows to solder a number of additional ground pins with low impedance connection to the HSMC ground node, this may work as well. Otherwise you should think about designing your own interconnect board.

    --- Quote End ---

    Does anyone know if such a daughter card is out there for purchase?