Teensy 4.0 5V to 3.3V Encoder RS422 Differential Line Receiver?

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JMW

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Hello,

I have a 5V encoder that I would like to connect to the 3.3V Teensy 4. I peeked in side the encoder housing and found that it has a chip number AM26LS31C(RS422 Differential Line Driver). I googled what chip should be used for the receiver and found number AM26LS32AC(RS422 Differential Line Receiver).

I looked at the data sheet but unfortunately I don't know how to interpret the info on it very well :( Does anyone have experience with these part numbers on a 3.3V Teensy 4? If the line receiver above won't work does anyone know of the correct one for the Teensy voltage range?

Also what would be the recommend way to connect a 5V encoder to the 3.3V Teensy when just using the A and B without the /A /B and not involving a RS422 differential signal? I googled and made a voltage divider but wants sure if there was something better or not.

Here is the link to the data sheets:
https://www.ti.com/lit/ds/symlink/am26ls32a.pdf?ts=1614573530569&ref_url=https%253A%252F%252Fwww.google.com%252F

https://www.ti.com/lit/ds/symlink/am26ls31.pdf?ts=1614529671742&ref_url=https%253A%252F%252Fwww.google.com%252F

Here is a picture of the encoder:
IMG_6877_.jpg IMG_6876_.jpg


Thank you,
 
A and #A form a pair, B and #B form a pair - those can be routed as twisted pairs, but twisting A with B will risk
crosstalk between the quadrature channels.

Each RS422 pair needs termination at the receiving end, a 120 ohm resistor is a reasonable match to CAT5 or similar cable.

Its best to use a differential receiver (the AM26L32 available: https://uk.farnell.com/texas-instruments/am26ls32acdr/rs-422-rs-423-line-receiver-5/dp/9851097?st=am26ls32)

For single ended output you can probably get away with a simple resistor divider as you think, using A/GND and B/GND
as twisted pairs, again terminated with about 120 ohms and check the voltages you actually get with a meter are suitable
for 3.3V logic - if not you'll need that receiver chip or at least a dual comparator - differential is the preferred approach.
 
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