Andrew Wood wrote:
> Im looking to design something which can sample 90 wires
> for the presence or absence of a DC voltage (50v, but can be taken
> down to say 5v with a voltage divider if needed).

Since your signals are slow, this can be done by multiplexing.  Brute force
would be a dozen byte wide tri-state line drivers.  You enable one at a time
to read its 8 lines.


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