gnupic: Re: [gnupic] adding led to gpsim mod_test
Subject:
Re: [gnupic] adding led to gpsim mod_test
From:
"Scott Dattalo" ####@####.####
Date:
14 Nov 2006 15:32:58 +0000
Message-Id: <62059.71.139.16.236.1163509543.squirrel@ruckus.brouhaha.com>
On Mon, 2006-11-13 at 14:57 -0700, Maxim Wexler wrote:
> Hi group,
>
> I can add a node and led to the breadboard in mod_test but not to the other
> side of the resistor. The new node has a voltage and the led appears to
> light but clicking 'trace all' just shows the four leads from the chip to
> the resistors. How do I put the node(s) on the other side of the
resistor(s)
> so I can add led(s)?
Hi Maxim,
The gpsim LED is modeled as though if it is buffered. So no resistor is
needed. However, if you do need a 2-terminal resistor for some other
reason then it's possible to emulate one with the switch module. The
switch is a true two terminal device. You can set the state of the switch
to be always closed and set the switch on resistance to the value you
like. Check out the switch regression test for examples on how the
switch's on-resistance can be changed.
Also, it should be pointed out that the resistor models in gpsim are
really pullup and pulldown resistors only; i.e. they're only 1-terminal
devices. The reason for this is mostly historical. It's only been since
the last release (0.22.0) that gpsim was capable of simulating a
2-terminal analog device, yet the pullup/down resistors have been around
for a long time. Finally to add more to the confusion, the pullup and
pulldown resistors can also act like DC power supplies; you can set both
the pullup resistance and pullup voltage.
Scott
