Simulator circuits as schematics

[prlaba]

I thought I would get other's thoughts and comments on this topic.

I'm currently designing a CPU that fully emulates the Z80 (using discrete components, not an FPGA). I'm currently using Logisim-Evolution to simulate its many circuits (the reason I'm not using Digital is another story).

I haven't created a single schematic yet. Instead I've created simulator circuits to serve as my schematics. Once I have everything working correctly in the simulator, I'll use KiCad to create the actual circuits.

(Someone posted a request here asking that Digital be tied more closely with KiCad, allowing Digital circuits to be imported into KiCad and vice-versa--a very big request!)

What this means is that I'm always trying to keep my simulator circuits as close as possible to my schematic circuits. Obviously I can't do that for every analog component (except things like switches, pull-up/pull-down resistors, etc.), but I can do it for most of the ICs I'm using in my design.

One of my annoyances with L-E is not being able to invert the inputs of many of its components, like RAM, ROM, flip-flops, counters, etc.--they're always active high. So I'm forced to include inverters in my circuits, even though those inverters aren't part of my schematics. (Digital does a much better job on that front.) The more I'm able to have my circuits match my schematics one-for-one, the better.

Are others using Digital (or other simulators) the same way? If so, how do you best show "variances" between your circuits and schematics? I place inverters "tight" against the IC's pin, to remind me that it's a "simulator only" part. In other cases I create a custom circuit with pins that have the right polarity.

Comments?