Problem with 4xxx logic gates - can you reproduce this?

One of the set of parts I am currently working on is a full set of four x two input logic gates from the 4xxx family for submission via git. Each part has sub-parts so that you can move the individual gates to wherever you like on the schematic. For me the part works fine, but el-j encountered an odd problem on his system:

each of the bottom right parts is displaced by 0.05in. I cannot reproduce this problem for the life of me.

Can some of you please try the XOR version of the part: 4070 4 x 2 Input XOR Gate.fzpz (15.5 KB) and tell me if you get the problem or not. If you do, please state exactly how you added the part, click by click, and at what zoom level please.

Many thanks.

When I move the individual gates around they snap to grid fine on mine.

I don’t know much about electronics but is the Q pin supposed to be connected to that black line that becomes a pin, because it’s red.

Thanks for the reply. You’ve lost me on the red issue (it’s late and I’m being thick) could you post a screenshot with scribble to show me exactly what you mean please?
If it’s what I think you mean, the two are connected together internally, so they both stay red until you connect something to one at which they should both change to green.

That centre Q pin on each gate is red, showing it’s not connected to anything even though it’s resting on that black dog-leg line that goes out the side and becomes a IC pin.

Yup, got what you mean. They should be internally connected, but looks like I missed that, thanks. I can fix that (I think) fairly easily.

I don’t know if you can get parts to auto connect in Sch like breadboard.

I’ve corrected the xml, but now I am getting random crashes… probably pushing Fz a bit past its limits…

Send me your latest .fzpz and I will take a look at it…

4070 4 x 2 Input XOR Gate.fzpz (15.4 KB)

This should help you out a little bit… You can’t use subscripts in your schematic; The name and numbers are rotated on center… by having two separate names/subscript they are both rotated on separate centers… They needs to be a single line. You also didn’t need all the sub-parts and buses.
IC-4070.fzpz (11.6 KB)

I’d already tried exactly that svg four versions ago. The point of the sub-parts was to allow the gates to be positioned separately anywhere in the diagram in a ‘straight line’ fashion, whilst still retaining the chip body with its ground and vdd connections and preserving the external pin layout. Here is an example of how this can be used for a simple two bit adder:


The chip ‘carcasses’ look dreadful currently, even without the terminal error on the Vdd; I can’t make them look any better. I might decide redo as two sets of parts; one without sub-parts but the correct pin order, another with sub-parts, but the pins not in order. The removes the need for the dog legs and related buses and should look neater. I was hoping to avoid having to work on twelve parts though.
Does the part crash yours though? It does mine when you try to connect the legs to anything; sometimes before that.

Your part crashed Fz as soon as I dragged it on to the board. I thought you were just trying to create the IC-4070 part. Although I see what you are trying to achieve… I don’t quite understand the principle behind it… I have never tried anything like this in Fz so I don’t know if it will work or not… This is just a tad out of my knowledge base… but it is interesting…

I like challenges. It came from needing 4070 gates on my robot’s quadrature encoder, to mix the signals together to give the full resolution. But then I thought “Why haven’t we got any of 40 series gate chips in Fritzing? They are a basic learning tool…” and I set out to make a general purpose reusable set. Several days of effort later and I am still fighting with them!
The lack of subscripts in Fz is a real shame - I know they are not part of the tiny svg profile, but they look much better. Even Inkscape you have to hand code them though.

Fritzing is open source, and probably because no body has volunteered to make them… Hint! hint!

That’s precisely why I am making them - the one I uploaded here is just the XOR chip - the git upload has all the basic six: AND, OR, XOR, XNOR, NAND, NOR. At some point I may get to some of the other devices (especially NOT gates) but at least there will be a good set for others to build on.

I’m on EE expert but why do the gates have to be movable, aren’t they fixed when you buy the chip.

Sub-parts are purely for schematic view. The discrete ICs tend to have several devices (opamps, gates, flip-flops, whatever) per physical chip. You may need to use each of those devices in completely different areas of your design. The schematic is much easier to read / understand if the parts are placed where they belong logically i.e. near the devices they connect to rather than where they physically are on the pcb or breadboard. Also, the chip’s physical pin layout tends not to work well in schematic view; If you tried to do the adder above with symbols fixed in their chips, the diagram would rapidly become spaghetti.

It seams like everything has to be a separate part.

OK, I have reworked part - taken off subscripts and split the part into two variations:


Left hand is multi-part but with logical pin layout. Right is physical pin layout single part.
4070 4 x 2 Input XOR Gate, multi-part.fzpz (13.0 KB)

4070 4 x 2 Input XOR Gate, single part.fzpz (13.2 KB)
The full set is on github. Please let me know what you think.

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There seams to be something wrong with the first one.

When I move the top and bottom gate thingys, it won’t snap back to the same position.