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Re: [RFC] Eeschema bus upgrades and new connectivity algorithm

 

“Bus Group” sounds like a group of busses, rather than a bus composed of groups.  People doing a layout might also be thinking in graphical terms when they see “Vector” (ie: the direction the bus goes in or something), rather than in mathematical notation terms.

Can we just call everything a Bus, and simplify the syntax to a single notation (so the existing vector would be “{A[7..0]}”?  Then we can just refer to “group notation” and “vector notation” when speaking about busses.

Cheers,
Jeff.


> On 14 Dec 2017, at 04:15, Jon Evans <jon@xxxxxxxxxxxxx> wrote:
> 
> Hi all,
> 
> As some of you know, I've been working on some new features for Eeschema that expand the capabilities of buses.
> These features are not yet complete, but I wanted to share my progress to get early feedback.
> 
> Since there are a number of things, I have made a ~4 minute demo video, in which I walk through them and discuss:
> 
> https://youtu.be/z6x0xiKgDIc <https://youtu.be/z6x0xiKgDIc>
> 
> In case you don't want to watch the video, here are the new features:
> The existing style of bus is now referred to as a Bus Vector (for example: "A[7..0]")
> New concept: Bus Groups, for adding arbitrary nets to a bus
> Defined in a list, separated by spaces, enclosed in curly braces. For example: "{DP DM}"
> Can contain bus vectors as well as plain nets, for example "{A[7..0] D[7..0] OE WE}"
> Can have an optional name in front, like "MEMORY{A[7..0] D[7..0]}"
> If you add a name, the resulting nets will have the name prefixed on the front, like "MEMORY.A7"
> New concept: Bus Aliases
> You can use aliases to define shortcuts for bus groups.
> For example, you could create an alias called "USB" that refers to the nets "DP" and "DM"
> Then, you can define a bus group as "{USB}" which will contain both of those nets.
> You can also add a label, like "USB1{USB}" which will result in nets "USB1.DP" and "USB1.DM <http://usb1.dm/>"
> Bus Aliases are editable through a new dialog, and saved with the schematic file.
> New tool: Bus Unfolding
> Right click on a bus, and you can easily break out any of its members into a bus entry, label, and wire.
> You place the label (and set the bus entry orientation) with the first click, and then can continue wiring.
> In order to support this work, I am also working on a new connectivity algorithm for Eeschema.
> This algorithm stores the resulting connectivity information with the graphical objects on the schematic, meaning that it's quite easy to look up what net any particular object is part of.  The new algorithm is also significantly (i.e. an order of magnitude) faster at generating connectivity than the current netlisting algorithm in my testing so far.  It will support partial updates of the connectivity when editing the schematic, so the net information will always be in sync when adding/removing/editing items in the schematic.
> 
> The combination of a faster algorithm and caching of the connectivity results in dramatic speedups when working with large designs.
> For example, Chris' motherboard project (which is a great benchmark, by the way!) takes several seconds to highlight nets in the current master branch, and with my changes, you can highlight any net instantaneously.
> 
> Although it is not yet far enough along to demonstrate this, I plan to use this new connectivity algorithm to generate netlists for export, and replace the existing algorithm entirely.
> 
> You can check out the code in my branch here, but be warned that it is not yet complete, so I am not yet proposing that anyone do exhaustive testing of it and report bugs (because I already know about many of the bugs you will find :-)
> 
> https://github.com/craftyjon/kicad/tree/bus_upgrades <https://github.com/craftyjon/kicad/tree/bus_upgrades>
> 
> Thanks,
> Jon
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