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Differential pairs

Sparkylabs

Firstly I'd like to point out that the CS video on differential pairs is just one level above non existent.

 

So as per the video I create "a pair" but I have 2 differential pair nets in my schematic, if I just click on one of the diff. pair symbols i see that it has a generic name like diffpair. Do I correctly assume (yes we have to use assumption instead of actual documentation!) that for multiple differential pairs this name needs to be specific to the pair or i will have 4 traces that belong to the same "pair" set?

  • The key is naming the nets correctly, for example MYNET_P and MYNET_N, the names should be the same but with a specific suffix. Once the differential pair marker has been attached to both nets and the PCB updates you will find the differential pairs available for routing. You do not modify the differential pair marker in any way, the net names define which tagged nets are treated as pairs.

  • OK so I got as far as trying to route the PCB. So diff. pairs between multiple points is a waste of time, once a pair between 2 locations has been done it's impossible to run a "pair" to the 3rd location. I ended up doing that by hand while noting that the connections must be point to point so both pins at both ends on the right side. I mean frankly the use of routing diff. pairs is just about usable.

     

    When will altium be "bothered" to both write a comprehensive manual and if they are going to waste their time making videos perhaps they can make complete videos, I am yet to see one that fully describes a function.

  • in reply to Sparkylabs

    Just tested with very simple design and you can have more than two connections. It's not intended to be a sensible design but it worked by routing each pair segment one at a time, i.e. complete one pair and then start routing the next pair segment.

    image

  • Yes I tried that but it wanted to go back to the pins further away instead of the ones closest, I just did the second pair by hand it's only 250Kb CANbus so not too critical although it makes sense to run the traces together.

  • in reply to Sparkylabs

    Worth a try left clicking as your route to set down the path and guide the interactive routing.

  • Yes I tried that, I'd end up with with 1 track routed ad the other just sitting there.

  • in reply to Sparkylabs

    I've had the misfortune to be forced to update a design in CS created by a guy who has left the company and agree that the total absence of a manual is crazy (just a bunch of reference web pages and Vault-based tutorial). I haven't yet tried to touch the diff. pairs.

     

    I now have the sales rep from Altium phoning me regularly wondering if we're going to spend £5k on Designer, which seems equally as crap and hard to use. I thought Mentor Expedition was bad but this...

  • in reply to boxy123

    This is the online help for 'Keyboard Shortcuts':

    An empty webpage! Awesome!

    image

  • in reply to boxy123

    Don't be surprised. Although I am assured long-awaited update is coming behind the main Altium designer update documentation is something they never seem to give a stuff about. I really do not understand Altium and I really do not understand why they don't just have one single programme with different levels of licence access. They have set themselves up for twice amount of work and in the process I just annoying the people they hope will make the jump to Altium designer. Never in my life at this rate.