Assertion for signal stability inside a window

In reply to alexkidd84:

Your requirements are not clear; I believe that this is what you are trying to express:
At (fell(a) && !b) then starting from the next clock “c” holds the value it had at the fell(a)
until a rose(a). At the rose(a), “c” can change value.


//my purpose is to check that 'c' is stable since a fell down (and b is low) 
    //and until a goes high again. 
    property p_cstable;
        bit v; 
        @(posedge clk) disable iff (!reset_n)
        ($fell(a) && !b, v=c )|=>  c==v s_until  $rose(a);
    endproperty 
    ap_c_stable: assert property(p_cstable);  

If this is not your requirements, then please re-express them again.
Ben Cohen
http://www.systemverilog.us/ ben@systemverilog.us
For training, consulting, services: contact Home - My cvcblr


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