Need Shift / Plexing Help please

Discussion in 'The Projects Forum' started by quant, Nov 24, 2009.

  1. quant

    Thread Starter Active Member

    May 21, 2009
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    I'm a bit confused in choosing the right approach for an automation system whereby:

    A thousand inductors need to be activated following a Serial pattern which for most parts move upwards. Like it would activate say inductors that push buttons numbers, 66,67,68, 192,193,859 etc. and then return to the beginning and start the second pass where all the above mentioned buttons will not be repeated and continue like this with followup passes until all 1000 buttons have each been pushed once and only once based on the desired pattern at hand. Therefore all in all there has been 1000 buttons that all have been pushed once each but through several passes when each pass pattern has been exclusive to itself.

    I have studied a lot and am wondering if a 4510 counter is the best solution or the 4017 or maybe shift registers etc.?
    Any guru advice will be appreciated.

    thanks
     
  2. quant

    Thread Starter Active Member

    May 21, 2009
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    My own thoughts are, I need to use a Micro Controller like the Arduino Mega with 54 pins that will do all I need to do except not enough pins!
    So, the question is what is the best way to add pins to it?
    Shift registers like, 74H....595? It seems to be a very good choice but I need to find answers to a couple of questions I have, like:
    1- How many Max. SR's can be cascaded? For 1000 Say LED,s, 125 will be needed and does that mean every time you need to push a button(turn on an LED) all the 1000 pins on all of the 125 SR,s need to be set?!
    2- Is it possible to reset all of them simultaneously and then just set the pins that are needed to high?

    thanks
     
    Last edited: Nov 24, 2009
  3. beenthere

    Retired Moderator

    Apr 20, 2004
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    You might find that crosspoint switching is a tad more efficient. Four 16 X16 blocks will make 1024 unique selections. Or one 32 X 32 matrix.
     
  4. quant

    Thread Starter Active Member

    May 21, 2009
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    Thank you for your advice but I have no idea what "crosspoint switching" is? Please recommend some good readz or explanation on the issue.

    thanks
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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  6. quant

    Thread Starter Active Member

    May 21, 2009
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    Multiplexers

    In addition to switches, Maxim makes a number of multiplexers (muxes). A mux is a special version of a switch in which two or more inputs are selectively connected to a single output. A mux can be as simple as an SPDT switch or come in 4:1, 8:1, 16:1, or even dual 4:1 and 8:1 combinations. The digital control for these higher order muxes is similar to a binary decoder with three digital inputs required to select the appropriate channel.

    A demultiplexer is basically a mux used backwards. That is, one input connects to two or more outputs based on the decoded address data.

    There are, finally, cross-point switches. A cross-point switch is usually an M x N device, whereby any or all of M inputs may be connected to any or all of N outputs (and vice versa).
    http://www.maxim-ic.com/appnotes.cfm/an_pk/638
     
  7. quant

    Thread Starter Active Member

    May 21, 2009
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