Every datasheet that I have looked at mentions the function of pins A, B and C but no mention of D and E. I'm unsure which one is the push button output and which one is the Ground pin. I'm currently looking at this one: http://uk.rs-online.com/web/p/mechanical-rotary-encoders/6234237/
Electrical – rotary encoder pin identification
encoderrotary
Related Solutions
As per documentation, connections would be following:
A — A line of encoder, use pull-up with controller input pin.
B — B line of encoder, use pull-up with controller input pin.
C — GND of encoder part
5 — VCC for LEDs and pushbutton
3 — pushbutton - one could use 10k pulldown since it seems it is switched to VCC
1, 2, 4 — LEDs
The LEDs have an "always present" VCC on pin 5 - so you would light them up by pulling their respective pin to GND with appropriate series resistor (470R - 1k2).
This simulates nicely in LTspice:
and you'll need the following links to get to the files you'll need to run the sim. Download all of the files into the same folder and then start LTspice by left-clicking on the .asc file.
https://www.dropbox.com/s/bubgfvl8ewj5v9g/Quadrature%20decoder.asc?dl=0 https://www.dropbox.com/s/lonoh1d3bucnf1j/74hc04.asy?dl=0 https://www.dropbox.com/s/i9tsv0cjzoof21j/74HC.lib?dl=0 https://www.dropbox.com/s/9h28abp72zhlynj/74hc00.asy?dl=0 https://www.dropbox.com/s/42dmlx4enjzu1op/74hc74.asy?dl=0
Best Answer
Wild guess: these two contacts are simply connected to the push switch, if present.