[sdiy] SPICE (was Re: Synthex Oscillator)

[rsdio at audiobanshee.com]

On Jul 12, 2017, at 2:10 PM, Neil Johnson <neil.johnson71 at gmail.com> wrote:
> Bob wrote:
>> Would you be willing to share the LTspice file? I'd like to make my own signal graphs by varying certain parameters of the analysis, particularly the time scale.
> 
> Do this list now accept small attachments?  Let me try.  You'll need
> to install the 74hc library from the yahoo group.
> 
> Note that it is not a complete simulation, just the 8-bit down
> counter, discrete DAC, resistors, and output capacitor, with the
> transistor saw reset.

Thanks, Neil.

Couple of things:

First, would it be possible to share the 74hc library? My Yahoo account has expired, or at least it isn't accepting my password for some reason.


I did find another 74hc.lib file, but when I use it I do not see any SPICE symbols when loading your file. I don't know whether the problem is that this library is missing some parts that the Yahoo library contains, or if it's more of a setup issue on my part.

https://www.classe.cornell.edu/~ib38/teaching/p360/lectures/wk12/l35/11.1/74hc.lib


Second, can anyone help get this loading on Mac OS X? I've used SPICE for decades, but it's always such a hassle to deal with libraries, symbols, and all of the manual configurations. I found a YouTube video online, but it's 20 minutes long and involves a great deal of manual editing of the SPICE files just to get different libraries working in LTspice.

If anyone knows a "standard" way of adding a third-party library to LTspice such that I can load Neil's unaltered file, that would really help. I assume that generic instructions might be useful for other members of the Synth DIY list.


Finally, I did seem to get the simulation to run in LTspice after I manually edited the SPICE directive to point to the full path of the 74hc.lib file that I installed, but the output waveform on the sawtooth capacitor was a steady +5V. The pulse input to the counter was so dense that it slows down the whole user interface as it draw 5 seconds of clock waveform. Maybe my 2.3 GHz laptop isn't fast enough?

Brian