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Creating Buses: Any Quick Way to Do it?

gervasi

Is there any way to create buses quickly in Eagle?

 

I attempted to create one wire, copy it, copy the pair, and repeat until I had 64 wires.  Then I named them and added labels, using NAME and LABEL.  Then I simply copied all the nets using COPY.  Everything looks connected, but they are not connected in the layout.  Even if I label these wires something like foo they stay unconnected.  I must delete both wires and name them individually.  Simply deleting one copy and then naming it does not work.

 

It appears I must draw a line, name it, and label it once for every time each net touches each pin.  A 64-pin bus that goes to three parts requires doing this 192 time!?  Is that true?

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    First, you have to define which nets are contained inside the bus. You can do this with NAME command. For example, for a typical 32-bit MCU bus, you have to change its name to something like this:

     

    AB[0..31],DB[0..31],RD,WR,CS1,CS2,CS3

     

    Then pick the NET command and click on the bus. A menu with net name selection will pop up and then you can connect the net wherever you need.

     

    More details are in Eagle help, see BUS.

     

    Unfortunately, I don't know any automatic method to place LABELs. But in the case of buses (and especially MCU buses), it is usually not necessary to label every single net - their function is evident from the schematic. In many cases, it is sufficient to label only first and last net from the bus group (AB0 and AB31 in my exaple above).