I checked on the simulation option "allow usim opt on schematics" and then "Q" on properties on the subblock and then "add" the speed string on the query box.
What I found out is that it is slightly faster, not a whole lot.
This test circuit A contains 3 blocks : bandgap and eprom and switching regulator. I have another similar test circuit B but all the 3 blocks (in ctr A) are hier. contained in a big cell. I just do a default option simulation, the sim speed is at least 4X faster (than ctr A) and the schmitt trigger in the oscillator subblock is working. I'm just puzzled by this. For ctr A, if using default sim option, the schmitt trigger would not work but it is fast.
Richardbernd wrote on Sep 27th, 2006, 2:51am:
Is there a way we can increase the accuracy in Ultrasim just for a small sub-block ?
You can use the Hierarchy Editor (HED) with a config view to assign
'sim_mode' or 'speed' for UltraSim for every cell or instance,
no mater how small.
Just enable 'View -> Properties' in the HED,
you will get two additional columns for 'sim_mode' or 'speed' in the HED.
And 'Allow usim_opt on HED' form the 'Simulation ->
Options -> Analog' in the Analog Environment (Artist), to get the stuff netlisted.