Hi! I’m new to KiCad, so please forgive my question should it prove misguided.
I’m re-creating a late 1970s vintage circuit board, and one of the “symbols” (components) is the 7406 chip.
Well, when placing that from the library, I see it neatly contains parts A thru F as separate elements, which is good. But it’s missing the usual part “G” which should contain PWR & GND, I think.
I do notice, however, that the 74LS06 does indeed have parts A thru G, where G is the PWR & GND piece.
I just wondered if this was intentional with the 7406 in the library, or just an oversight?
Then, do I need to manually create the “G” part with the PWR & GND when using the 7406 vs the 74LS06?
Sorry, for each inverter, I only see two leads each. Please forgive my ignorance here, I’m having trouble following… Leads 7 and 14 are missing, but all others are there. See my picture at
“Do you have a personal library to place your own symbols?” I’m muddling through figuring out how to build my own now. But I’ll gladly accept any pointers from the community, thanks!
To make visible, choose which of the six inverters you wish to show pins 14 & 7.
Open your Symbol Editor and place the unit from the 7406 you wish to show the power pins in the editor.
You will notice the writing and small circle (top and bottom centres of the outline) in blue.
Right mouse click in or just above/below each blue circle outside the box. This opens the pin properties.
Above the preview box in properties click “visible”… Done.
To create personal libraries follow this and then this. Both are in the FAQ at the top of this page.
When you have your own libraries you can copy the 74LS06 into your personal library and then just re-name it to 7406 and you will have the 7 parts with the triangular inverters.
If you want instructions for this please ask.
You can also just re-name the 74LS06 to 7406 by changing its Value after you have placed the gates on the schematic but this is not great practice as it only shows on this schematic and is tedious as every gate will need to be altered.
At your picture I see small circles at top and bottom of each gate symbol. I suppose this are power pins defined with length 0. I can’t check this myself as I don’t have KiCad libraries at my working PC (I use only my own libraries).
Thank you so much for this very in-depth explanation! I’m so glad I asked! It would have taken me a long time hunting across the internet to figure out that’s how this worked…
Actually, I’m having the same problem with the 7408, too. Maybe to avoid this confusion, these symbols could be updated in the default library? And those circles of “pins with 0 length” are very confusing, and contradictory, since each of the 4 modules has 2 of them, implying that each of them need VCC & GND, when the whole package is only a 14 pin package with only 2 pins for VCC / GND respectively. The way it’s set up, all those zero pin lengths for VCC & GND make it a 20-pin package, which shouldn’t exist.
Place the symbol that works for you and after the sections have been placed, click the bulk edit fields icon (looks like a spreadsheet) and you can tweak the IC number there.
Sometimes it’s faster to use a symbol of a pin-for-pin equivalent part and just rename it after placement.
My preference is for the preceding (74xx) library rather than the (74xx_IEEE) library.
Once you have your own library, you can place the 74LSxx series from the 74xx series in your own library and rename the chips to 74xx or for one offs, rename the 74LSxx 's to 74xx on your schematic.
Well… when I had to fix a product that must have had over a thousand IC’s in it; I was very happy the schematic did not have 2 thousand extra lines drawn to try to follow.
I guess, with KiCad, one can always draw a label at each connection, but that is still going to take up quite a bit of real-estate on a paper schematic; more page flipping to find where the signal goes next.
Ah!
It wasn’t a wish, it was a preference. I don’t like the IEEE symbols.
Having said that, I have to confess, 1980ish was about the last time I used TTL in any volume.
For example, the board I just uploaded made use of hidden power pins feature. Had this feature not been used an additional 42 symbols and connections would have had to be manually made.
It is not my intent to tell anyone that one way is better than the other; but the different ways may use quite different amounts of printer ink.
I suppose it depends on familiarity. I was brought up with the and/or/buffer shapes as shown in the 74LS and 4000 series. I find it difficult to read the 74 IEEE shapes. Too many look-alike squares used for gates.
