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Pack_of_lone_wolves's avatar
Pack_of_lone_wolves
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1 year ago
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Routing constraints in QPP

I'm aware of Logic Lock feature in QPP, through which I can restrict the placement of a design node on the FPGA chip. How do I restrict the routing of a data path as well as a clock path in QPP? like placing two earlier distant modules near using logic lock may reduce the data path delay but may increase the clock path delay at either the source or destination node.

I'd like to restrict the such path length or at least direct the tool to go for best minimum possible.

20 Replies

  • Pack_of_lone_wolves's avatar
    Pack_of_lone_wolves
    Icon for Occasional Contributor rankOccasional Contributor

    Using Arria 10 device and QPP v 20.1.

    I'd like to experiment with what you just said, however, I feel that if I try splitting the logic into different areas using logic lock, I might end up worsening the existing delays.

  • Pack_of_lone_wolves's avatar
    Pack_of_lone_wolves
    Icon for Occasional Contributor rankOccasional Contributor

    What I also suspect and have a question is that what role can pin planning in assignment editor can play in making timing closure more difficult? The project has multiple clocks and I feel that position of the clock pins is responsible for introducing large clock skews.

  • KennyT_altera's avatar
    KennyT_altera
    Icon for Super Contributor rankSuper Contributor

    That is correct, synchronization of the reset is usually a common practice that we do in FPGA. Especially we want to check the recovery and removal time.

    Unless you send us your design, it will be hard for me to analyze on this., For your situation, leverate the DRC to look for high tension register, and start duplicating it. I will send you more steps that can be automate after you pipeline the register.


  • KennyT_altera's avatar
    KennyT_altera
    Icon for Super Contributor rankSuper Contributor

    Noted, if you have a follow up question, Please login to ‘https://supporttickets.intel.com’, view details of the desire request, and post a feed/response within the next 15 days to allow me to continue to support you. After 15 days, this thread will be transitioned to community support. The community users will be able to help you on your follow-up questions.