Asti's Notes
FP, Rx, EDA
Daisy chains in Altium
Easily daisy chain any number of sub-circuits

Why a way to daisy-chain?

If you wanted to daisy chain any component the conventional way, say a bunch of WS2812s on your board, you'd be making multiple instances and manually wiring them to each other.

Steps

  1. Make a sub-sheet out of the components you want to daisy chain (unless it's not in one already).
  2. Change the designator of the sheet to Repeat(name, 1, N) where N is the number of items you want. E.g., Repeat(SW, 1, 8)
  3. Change the daisy chain input port to Repeat(DIN)and output to Repeat(DOUT) - the usual
  4. Connect DIN to a bus with net label DIN[2..N]. E.g., DOUT[2..8]
  5. Connect DOUT to a bus with net label DOUT[1..N-1]. E.g., DOUT[1..7]
  6. That's it. Just connect the two buses together and you're done.

Your daisy chain's input will be DIN1 and the output should be DOUT<N>. (i.e., DIN1 and DOUT8)

Example

The final schematic should look something like this:

  • It's not too much effort to set this up.
  • You can simply change the values for N=16 or N=100 and the daisy chaining will be set up correctly
  • Since the sheet is repeated, you can use room commands for laying out and ordering all of them - and you only need to route one of them
  • Automation caveats apply.

Note

You might need to place a NOERC on the output with “nets containing multiple names”, because technically DIN(N) is connected to DOUT(N+1)


Last modified on 2018-12-21

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