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Topic: divider/counter chip (Read 3 times) previous topic - next topic

mmcp42

very likely
d******d expensive though
:)
there are only 10 types of people
them that understands binary
and them that doesn't

pwillard

#11
Jan 29, 2011, 05:15 pm Last Edit: Jan 29, 2011, 05:18 pm by pwillard Reason: 1
To me... it sounds like you are talking about a 74192 or 193 (presettable up/down counter)

http://www.datasheetcatalog.org/datasheet/motorola/SN74LS193.pdf

In the 80's, I made a COUNTDOWN DARKROOM TIMER with these that you could preset to the number of seconds you wanted the enlarger light to be on.  (Preset using BCD thumwheel switches)

mmcp42

looks a bit more likely!
not overly expensive
need to tie a couple together to get 8 bit but that's doable

thanks for the sterr!
there are only 10 types of people
them that understands binary
and them that doesn't

Metalfan1185

I agree with Pwillard.

You could use one or two 74ls193 4 bit up down counters and use the 74154 as a de-multiplexer.  A few NAND Gates (7400) to toggle which one is counting and thats that.

mmcp42

Yup, that's probably the way I'll go
Busy prototyping in software before I commit to metal
Thanks all for the input :)
there are only 10 types of people
them that understands binary
and them that doesn't

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