Showing signal direction

Hi all, I am relatively new to the schematic editor. Is there some way to indicate (and visually show) the direction of a signal on a wire? It would really help in understanding the signal flow in a circuit. I notice that the library editor designates pins as input or outputs (“electrical type”) but that information does not get visualized in the schematic view. Even to be able to put arrow heads on wire segments would be enough to make the schematic more self-explanatory.

Thanks for any ideas.

Some make the practice of drawing the schematic so that the signal flow is left to right on the page; similar to reading text.

As you look at a variety of schematic symbols in the libraries, you will note that the pin-out typically is such that inputs are on the left of the device, and outputs are on the right. This makes designing for the “left-to-right” method sort of built-in.

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I do tend to layout left-to-right but even a moderately complex logic design will not conform to that. The best I could come up with is to edit the component symbols and add pseudo arrow heads on the edge of the component. Unfortunately you cannot fill a polygon so it is just an outline. Not great, but it does help the readability of the schematic:

You could have helped yourself by using the symbol suggested by the data sheet, inputs on the left, output on the right. If the idea of the schematic is to show the design rather than the physical layout. Using global labels makes the direction clear, and also helps reduce hard to follow spaghetti wiring.

It’s also good practice to have power rails at the top and gnd at the bottom. I think if you followed these practices, you wouldn’t have so much need to create non-standard symbols.

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First thing I noticed was the symbol pin numbering; listed as if a DIP part. This is clearly NOT inputs on the left and outputs on the right.

The DataSheet symbol is actually partly readable/understandable, even though I have not read the DataSheet. Separating the inputs and outputs greatly improves the readability of the schematic.

The datasheet also provides a good model for the input connector

Although the datasheet shows another IC with right to left order, so maybe it was just luck.

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Thanks for all the pointers. I was indeed thinking about the physical chip pinout when I first created the 1402 component. Better organization of the pins would help the schematic layout (and top/bottom power rails too). The TORX173 came from one of the built-in component libs.

Global labels I am not so wild about. They can remove lots of lines from the schematic, but make understanding it a seek-and-find exercise in matching label names. I prefer the explicitness of connecting lines if the net is all on one page.

I am also using a Xilinx programmable CPLD in this design… and so the supplied library component cannot arrange left-in, right-out convention. Still would like a standard way to visualize input/output direction on component pins.

Not from Wavefront, they discontinued it a long time ago. But Coolaudio makes an exact pin-for-pin clone - the V1402 which is what I am using. They can be purchased in single quantities from CabinTech Global.