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RTL compiler inner clock definition

EvgeniySUAI

 Hi developers! :)

I've faced with problem with defining of timing constraint in RTL Compiler. In my design inner clock is generated based on signals from two input pins (xor on two signals actually).  How can i tell to RTL Compiler, that this inner signal is a clock? I tried create_generated_clock, but it allows to define generated clock only based on some input pin. This is unacceptable for my design. It also seems to me, that create_generated_clock can be used only for creating clock on outputs of deviders or pll.

Thanks in advance, Evgeniy

 

 

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  • grasshopper
    HI Evgeniy,

    Can you please describe the constraint and circuit in full. You can define a clock on an internal node if you wanted to and this is also the case for generated_clock. The question is not so much what constraint you were trying to apply but what behavior you were trying to model since whatever constraints you apply can have different impact on how tools handle it down the flow. You can start by simply defining a clock on the pin in question. A generated clock needs to have a master source whether an I/O or internal node. Sounds like you have an oscillator or some sort of clock inversion circuit. If it is the latter, I do not think you need to redefine the clock if the source propagates there.

    Gh-
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  • grasshopper
    HI Evgeniy,

    Can you please describe the constraint and circuit in full. You can define a clock on an internal node if you wanted to and this is also the case for generated_clock. The question is not so much what constraint you were trying to apply but what behavior you were trying to model since whatever constraints you apply can have different impact on how tools handle it down the flow. You can start by simply defining a clock on the pin in question. A generated clock needs to have a master source whether an I/O or internal node. Sounds like you have an oscillator or some sort of clock inversion circuit. If it is the latter, I do not think you need to redefine the clock if the source propagates there.

    Gh-
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