Isolate uart of two MCu

[A2]

I have to isloate uart of two MCU with the help of optocoupler.
I have made a circuit which I had attached.

is it the correct way to do?
For me its looks ok.

[David_AVD]

I assume that you're not wiring those 4 pin connectors 1-1 ?  (one is "upside down")

[David Hess]

That looks like it will work but it will be slow.

It may be worth studying how the MIDI interface works.  It uses optocouplers for isolation at each receiver.

[mij59]

Hi,


For "high speed" you could use a 6N137 opto coupler, or digital isolators like the AD ADUM series.

[David Hess]

If the optocoupler provides access to the base of the transistor like the CNY17 does, then there are various options to speed it up if additional signal conditioning is added.  Usually this takes the form of resistance between the base and emitter to lower the storage time but since this lowers the gain, additional external amplification is needed.

For slow applications, this is not needed.

[fcb]

It all depends on data rate (baud).  Your 10K pull-up on the photo-transistor looks a bit small in my experience.

[David_AVD]

I use 6N137 optocouplers for up to 250Kb (DMX) speeds.