Hspice Tips

Last modified: Wed Mar 3 05:27:18 2004

Hspice 101

Manual on-line?
See your local CAD support.

Graphics

How to run mwaves?
Avant! finally changed its name from mwaves (Meta Waves) to awaves (Avant! Waves). There was an alias in the previous version, but they deleted that alias, too. You should use awaves now.

I don't like awaves. I can't run awaves. Is there any other tool?
Right now (11/2/2000), there are some problems in 98.X with SUN Ultra machines. ECE/ORST people can use awaves on HP machines.
I prefer hsplot to awaves. Unfotunately hsplot runs only on HPs, too.

What is hsplot? How to use hsplot?
Hsplot is the previous tool for viewing the waves. It is older than awaves and even gsi. But it is much faster and simpler and more stable than others. I still use it for a small circuit block and for my most of simulation.
Unfortunately Meta-software was bought by Avant! and Avant! changed the output format for graphics. There is no manual description about how to use hsplot because it is now un-supported software from Avant!. But again it is more stable and simpler, so usually we don't need their support too much. Please try to use this: 

       .option post post_version=9007
Don't worry to put this option. Your new awaves reads this old format, too. You just get more freedom.
To invoke hsplot, type: 

       % hsplot

Do you have a manual of "hsplot"
I tried to make it by myself since Avant! doesn't like it. But I find this site: Hsplot. Enjoy it.

Debug

TRAN: internal timestep too small in transient analysis
Here is how to solve it. Basically, we will have this error when total simulation time is too long compared to the highest frequency, which is steep rising/falling time of digital clock, for example. Try each step individually, first. When you can't remove the error, you may combine below tricks. However I can usually remove the error before I try step 4.

  1. Increase rise-time and/or fall time of the pulse
  2. Increase ITL4 between 25 and 500, (default is 10)
  3. Change TRAP method to GEAR
  4. Change MAXORD to 3, 4, 5, and 6
  5. Change TRTOL to 25 (default is 7)
  6. Change LVLTIM from 2 to 1
  7. Increase TNUM
  8. Change ITL4 to 100
  9. Reset above, and set these
    	      RELTOL = 0.01
	      ABSTOL = 1.0e-9
	      VNTOL  = 1.0e-4
	      LVLTIM = 1
	      METHOD = GEAR
	      MAXORD = 2
	      TNUM   = "pick big number"
	      ITL4   = 100

How to change the default printer
You can edit your own meta.cfg file. The original and default meta.cfg file is located at /usr/local/apps/meta/97/meta.cfg in ECE dept now. You should check its location by yourself. You can copy and modify it. Your modified meta.cfg file should be in your home directory.

My outputs are zeros when they are less than 0.5 uV. Why?
I thought it was a BUG and I asked Avant! but no reply yet. I also asked NTT-AT (Japan's distributor) and finally I got the solution from NTT-AT (Aug. 23, 1999) after I asked them on Aug. 17, 1999. They created new option VFLOOR in 1993 (Version 93A.02) and its default value is 500 nV. We can control the minimum value for printout. WHY? I would say they are ignoring analog circuits designers. For digital guys, they just want to see "L" instead of 100nV. :-(

Anyway, here is what I observed before:

BUGs in 98.2 Star-HSpice
Avant! created the following BUGs into my favorite Meta's HSPICE. Because they don't give us technical support web pages, I will give this information for your convenience.

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