On Thu, Sep 15, 2016 at 06:54:59PM +0100, Dan Weatherill wrote: > Hi all, > I've been using kicad for about 5 years. Recently (mostly with CERN > changes - especially differential pair support), it's become suitable for > more and more of my more complex projects (I'm switching from Altium > Designer). I also have about 10 years experience working on c++ projects, > but am not what you would call an "expert". > A feature I've been especially missing in Kicad for several projects is > something akin to Altium's "harnesses": that is, basically a "bus-like" > entity which contains named signals, possibly of different types (e.g. > input, output, passive etc). Harnesses are very useful for drawing things > like e.g. SPI, I2C, CAN connections which have well defined named signals. > Harnesses contain better information than numbered busses for this > application, but can help with schematic "overcrowd" when wiring up chips > with many signals such as micros, FPGAs etc. This is often a big problem > especially in hierarchical designs where to do this using wires requires > possibly dozens of hierarchical labels.
I _really_ want this. IIRC I submitted a wishlist item for it ages ago, and nothing ever really became of it (and as usual I ran out of time to implement it myself). These are hugely useful in complicated designs. > I've been thinking about implementing this for a while, but have not started > due to being aware that eeschema is under fairly major re-factoring at > present. > > With guidance from c4758p on #kicad, I think that this feature could be > implemented with the following steps: For anyone who doesn't know yet, I'm c4757p on #kicad, or c4758p when my connection's dodgy ;) > 1) add two new items in NETLIST_ITEM_T enum, likely called NET_HARNESS and > NET_HARNESSLABELMEMBER, which have similar functionality to NET_BUS and > NET_BUSLABELMEMBER but for harnesses > 2) several changes to connection rules in netlist.cpp (most majorly in > pointToPointConnect() and a new function > NETLIST_OBJECT_LIST::connectHarnessLabels() ) > > 3) minor UI additions (harnesses can be just a different colour wire, and > harness-to-wire connections at this time can be just the same as wire-to-Bus > connections) In light of the proposal to add line color support to eeschema, I'd like to see something different than just a color. They look like this in Altium: http://techdocs.altium.com/sites/default/files/wiki_attachments/231555/Harness+Connector+with+entries.png A point wrt. UI is that when eeschema is converted to GAL, a good bit of the UI code will need to be ported or thrown out. I don't think that should necessarily stall development, but I'd warn you to be prepared and write your code to be properly modular and easy to port. :) > > The main question usability wise would be how to label harnesses. I see two > possible options: > 1) new syntax: a harness has a label using new type of brackets, with > harness type in brackets, e.g. an I2C bus called A would be "A{I2C}". The > wires would be then labelled exactly like bus labels, e.g.: "A[SCL], A[SDA]" > > 2) bus-like syntax: using same brackets as bus syntax, but make a harness > when the contained type is a string rather than numbers, i.e. "A[I2C]" for > harness label, "A[SCL], A[SDA]" for harness members. I haven't given this a huge amount of thought yet. Does anybody see a reason for this to me more than just a stylistic detail? We discussed this a bit on IRC and concluded that it would matter if harnesses were a subclass of buses, but if they're a separate object I don't think so. > > > I guess there are implications for the schematic file system which I need to > understand, and need to be discussed. As far as I can see, we just need to add a 'harness' type similar to the 'bus' type. > > All suggestions welcome, and I hope to start working on this soon. > Thanks, > Dan W > > > _______________________________________________ > Mailing list: https://launchpad.net/~kicad-developers > Post to : [email protected] > Unsubscribe : https://launchpad.net/~kicad-developers > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~kicad-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~kicad-developers More help : https://help.launchpad.net/ListHelp
