Re: gEDA-user: gEDA, where are the loadable examples?

[Charles Lepple <clepple@xxxxxxxxx>]

On Sun, 13 Mar 2005 15:42:22 -0500, Gene Heskett
<gene.heskett@xxxxxxxxxxx> wrote:

> I don't have to have the 82c55, but if I did, I could maybe do two
> boards and let ngspice do some optimizing.

There is an 8255A symbol in the micro subdirectory of the geda-symbols
package, but it's just a graphical symbol. That is, you can draw a
schematic with it, and if you have a generic 40-pin DIP footprint, you
can put it on a PCB. (This particular symbol file has pin numbers
associated with it, which lets you use it with a generic footprint.)

If you try to make a spice netlist, I don't know what would happen,
but I would bet that it's not what you intended.

> How is ngspice at simulating analogue circuitry thats supposed to be
> running in pwm mode?

Not sure about ngspice in particular, but in general, spice-like
modelling systems can easily handle simulating transistors operating
in saturation (as most PWM systems are designed to run). If you have
an integrated PWM driver chip, you probably won't be able to easily
simulate overcurrent limiting, but if you pick a transistor model with
similar output characteristics, you can model the non-limited
operating region.

-- 
- Charles Lepple