distribution problem?

Discussion in 'General Electronics Chat' started by Gibson486, Jan 6, 2015.

  1. Gibson486

    Thread Starter Member

    Jul 20, 2012
    199
    12
    I am trying to make this board that will enable to to program multiple similar chips with just a push of a button. To do this, I just hook up my MKII programmer and fanout the signals and control which IC gets the clock with a multiplexer. It worked when I did it with 2 Arduinos. However, I made the board and it seems to only program half the time (there are about 18 programmable chips on a board). The error is usually that there is a communication error. I am figuring that maybe when I go past 4, I start getting power consumption issues or maybe it is a signal integrity thing. Any thoughts?
     
  2. #12

    Expert

    Nov 30, 2010
    16,252
    6,751
    Current limitations, speed, length of wiring, parasitic capacitance...
    High frequency stuff can get very picky.
     
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
    5,986
    3,730
    current draw and fan-out are the likely issues. As #12 said, the stray capacitance that makes nice digital signals look like weak sine waves can also be an issue with bigger boards.
     
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