I’m going to design a breakout board for a component, the component has a couple of connectors but at the end it will belong to the same footprint (the connectors need to be precisely positioned to each other). I was planning to make a multiple part symbol, until I realize the the numeration of the different connectors is not unique (connector J1 has pins 1-38, connector J2 has pins 1-58, etc.)
My solution was to user a prefix for the pin number (J1_1, J1_2, J1_3, etc) until I realize that there is only 4 digit available for this (J1_10, J1_11, etc, all turn to J1_1), I shorted my scheme but it is less readable.
Does anybody have an idea how this can be implemented ? Am I doing something wrong and there is an easiest way to do this ?
Thanks !
Edit: I forgot to provide the my software version
Application: kicad
Version: 4.0.4-stable release build
wxWidgets: Version 3.0.2 (debug,wchar_t,compiler with C++ ABI 1009,GCC 5.2.0,wx containers,compatible with 2.8)
Platform: Windows 7 (build 7601, Service Pack 1), 64-bit edition, 64 bit, Little endian, wxMSW
Boost version: 1.57.0
USE_WX_GRAPHICS_CONTEXT=OFF
USE_WX_OVERLAY=OFF
KICAD_SCRIPTING=ON
KICAD_SCRIPTING_MODULES=ON
KICAD_SCRIPTING_WXPYTHON=ON
USE_FP_LIB_TABLE=HARD_CODED_ON
BUILD_GITHUB_PLUGIN=ON
It helps you with the prefix part. Template allows you to position the connectors precisely with each of them being one footprint.
This also allows each connector to appear separately in the position file if you want your pcb to be assembled by a machine.
The separation of function needs multi unit symbols as you already wrote. (creating a specialized connector symbol also allows you to define the electrical types for this special function. This means ERC can help you more than otherwise.)
The only real issue I see is how it will look on the silk screen. With snapping the pin alignment will be precise. In building the board you can still use the one part. If you want them to be considered 2 separate blocks then just build them as such and butt them up in PCBnew. As always, maybe I’m missing something?
Thanks a lot for your feedback guys, I tried both approaches, but I went with the original idea as outlined by Andy_P, because I’ll most probably be using this part as component in other projects and having it in a library makes it easier to handle.
How would you use this for instance to describe and include headers for an arduino mega in a schematic and bill of materials.
If I use the symbol from the sparkfun libraries, it exports to the BOM as one entry whereas really what I would need to purchase would be some 8 pin headers, a 2x18 header, a 6 pin header. If I understand correctly, making a multi-part symbol wouldn’t be able to represent this properly in the schematic and the BOM which is important as I don’t want someone to just add the BOM and buy an arduino rather than the required connects/headers.
Maybe I’m missing something but whenever I’ve seen a multi-part symbol, it still registers as one entry in the BOM as they are typically used for IC’s with multiple internal circuits rather than being made of several individual components.
Edit
I want to mention I’ve looked at the template for how an Arduino_Mega_R3 shield can be started. I suppose If I was careful enough, I could include that schematic and load the board layout but I think it’d be a useful feature to incorporate this template into a sort of parts/footprints library structure.
In your case i would use a template. The template then has one specialized symbol per connector (with pin names that help identify which pin has what function. Also set the pin types correctly such that ERC can help you.) plus a zero pin symbol connected to a zero pin footprint for tracking the arduino board itself (this symbol could include the 3d model and arduino outline)