Hi,

I'm trying to generate digital (and analog) output signals for certain input voltage behavior. My code for generating the digital signals looks like this :

parameter real vbathigh_thres = 3.4;
parameter real vbatlow_thres = 3.0;
   always @(above(V(vbat) - vbathigh_thres))
   begin
           vbatlow18  = 1'b0;
           vbathigh18 = 1'b1;
       end    
         
   always @(above(vbatlow_thres - V(vbat)))
   begin
               vbatlow18  = 1'b1;
               vbathigh18 = 1'b0;
     end

When I simulate this model in AMS Spectre by varying vbat from 0-5V, it shows me the expected behavior, however when varying from 5-0V it doesn't work. The code seems to be unable to detect that vbat > vbathigh_thres at the start of simulation and put vbathigh18 = 1, vbatlow18 = 0. See attached waveform (blue - V(vbat)). Is there something wrong with the code or the way I simulate it.
The LRM makes a mention about : "above() function is almost identical to the cross() function, except that it also triggers during initialization or dc analysis. It generates a monitored analog event to detect threshold crossings in analog signals when the expression crosses zero (0) from below."

Is it this crossing from below part causing the problem? Why isn't it triggering properly during initialization?

Thanks
D

incidentally... it seems to be a version issue! works on some, not on others. Reported it to cadence. Thanks boe for mentioning it!.. made me try different versions. Had been trying to code it differently thinking it was my mistake, but to no avail.

IUS 8.10s7