[eispice] Re: behavior test case problems
- From: Charles Eidsness <charles@xxxxxxxxxxxxxxxxxxxxx>
- To: eispice@xxxxxxxxxxxxx
- Date: Mon, 18 Dec 2006 18:47:03 -0500
Hi Jon,
You're not abusing, you're stretching. :) It was intended to be used in
that way, but you're the first to try it.
It looks like I have some work to do on error messages. They're way to
cryptic, especially for the new PyB device. I'll see what I can do.
Your B-Element based model uncovered a bug in the calculon library's
parser. It requires a space between the '-' sign and constants. I've
fixed it in my stream and it will be fixed for the next release but for
now you can just add a space. Also, the B element doesn't recognize the
'GND' identifier, it only recognizes 0 as a ground indicator. I can add
GND as well but I'm hoping that as soon as we get this PyB element
working the only use for the old B element will be for porting in Spice3
decks which only use 0.
If you change:
d.pmosx = dev.B('4', GND, 'i',"0.5*2e-6*(v(1,4)-0.7)^2")
to:
d.pmosx = dev.B('4', GND, 'i',"0.5*2e-6*(v(1,4) - 0.7)^2")
and:
d.nmosx = dev.B(4, GND, 'i',"0.5*5e-6*(v(4,GND)-0.7)^2")
to:
d.nmosx = dev.B(4, GND, 'i',"0.5*5e-6*(v(4,0) - 0.7)^2")
The simulation runs, until it fails to linearize. I'll have to fiddle
with the simulator to get it working further than that, which will take
a little bit longer. I'll post again once I get it working.
The two PyB based models had a couple of typos. The lines:
def model(self, Vg, Vs)
should have a 4th argument (because you defined 3 input arguments), you
can change them to something like:
def model(self, Vg, Vs, Vp)
Also, for the second model the if statement references vtp but it should
reference vtn, i.e.:
if ((Vg - Vs)> self.vtp):
should be:
if ((Vg - Vs)> self.vtn):
Once you make those two changes it should run as far as the 'failed to
linearize' as well.
I'm sure with some useful messages those two typos would have popped
right out. It's tough to debug when every error message is "TypeError:
bad argument type for built-in operation". I'm guessing it's really
referring to some bug in the way I'm passing error messages between C
and Python, I'll look into it.
Thanks for having patience as we work through the bugs, and I'll get
back to you on those 'failed to linerise's'
Cheers,
Charles
Jon Choy wrote:
> I've tried a couple of behavior cases that don't seem to run. I hope I
> haven't abused the capability. I'm simply seeing if a mos divider circuit
> will work. I have two devices and behavioral nmos and pmos with the gate,
> drain of both the pmos and nmos tied together. I have tried three different
> cases. Let me know what you think.
>
> #!/usr/bin/python
>
> from eispice import *
>
> # -- PyB Defined Model --
> class pmos_sat(dev.PyB):
>
> def __init__(self, p, n, g, s, b, kp=2e-6,wp=2,lp=1,power=2.0):
> dev.PyB.__init__(self, p, n, Current, v(g), v(s), v(b))
> self.kp = kp
> self.wp = wp
> self.lp = lp
> self.vtp= 0.7
> self.betap = kp*wp/lp
> self.power=power
> def model(self, Vg, Vs):
> if ((Vs - Vg)> self.vtp):
> return 0.5*self.betap*(Vs - Vg - self.vtp)**self.power
> else :
> return 0
> class nmos_sat(dev.PyB):
>
> def __init__(self, p, n, g, s, b, kn=5e-6,wn=2,ln=1,power=2.0):
> dev.PyB.__init__(self, p, n, Current, v(g), v(s), v(b))
> self.kn = kn
> self.wn = wn
> self.ln = ln
> self.vtn= 0.7
> self.betan = kn*wn/ln
> self.power=power
> def model(self, Vg, Vs):
> if ((Vg - Vs)> self.vtp):
> return 0.5*self.betan*(Vg - Vs - self.vtn)**self.power
> else :
> return 0
>
> # Now to use the model
> kp = 2e-6
> wp = 2
> lp = 1
> vtp= 0.7
> betap = kp*wp/lp
> power=2
> kn = 5e-6
> wn = 2
> ln = 1
> vtn= 0.7
> betan = kn*wn/ln
>
> d = Deck('PyB Defined Behavioral MOS divider')
>
> d.V0 = dev.V(1, GND, 3.3)
> #d.pmosx = pmos_sat(4, GND, 4, 1, 1)
> #d.pmosx = dev.B('4', GND, 'i',"0.5*betap*(v(1,4)-vtp)^2")
> d.pmosx = dev.B('4', GND, 'i',"0.5*2e-6*(v(1,4)-0.7)^2")
> #d.nmosx = nmos_sat(4, GND, 4, GND, GND)
> #d.nmosx = dev.B(4, GND, 'i',"0.5*betan*(v(4,GND)-vtn)^2")
> d.nmosx = dev.B(4, GND, 'i',"0.5*5e-6*(v(4,GND)-0.7)^2")
> d.rout = dev.R(4,GND, 100000)
>
> d.op()
>
> d.plot()
>
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