[sdiy] 4-bit encoder?

[David G Dixon]

Roman said... 

AFAIK there's no 16-bit encodr in a chip.
Knowing you this bit I'm aware that using CPLD, or microcontroller, or SMD
is out of the question so you have to cascade two 8-bitters.
That's almost the same as one chip, imagine it as one narrow 32-pin DIP long
package. No additional logic needed just 2 chips and wires.

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Yes, that's what I figured.  I have no problem making one from
(4532/4532/4071).  There are already over a dozen logic chips in this design
(but they're all really cheap), because I refuse to learn how to use
microcontrollers.  Most of the issue is bus isolation, and I need 29
tri-state buffers, so there are 8 '126s on the board.  The main issue with
all of this is the routing of the logic lines through the 29 buffers.  They
are connecting 12 decoder outputs to 12 encoder inputs, and being controlled
by a bus of 7 control lines, many of which are also going through both
2-input and 3-input OR gates, so it's all a big tangle.  What I ended up
doing was putting sockets right next to the '126s, and doing all the ugly
routing on a separate board which will plug into all the sockets.  In this
way, the logic board is very small and very clean.