Bidirectional i2c isolation - arduino

Hey, I recently bought the “ISO1541 I2C Data and 1KV Power Isolator Bus Handler I2C Mini Module” in order to create optically isolated i2c communication between 2 arduinos.

I used your product because it looks like it should isolate i2c bidirectionally as well as providing regulated 5v power to another arduino.

The issue is that I can’t seem to get bidirectional i2c data. I can only send data from the arduino on low voltage and can only read it from the arduino on the high voltage. I cannot send i2c from the high voltage to the low voltage arduino which is the whole purpose of isolating the signal.

The purpose of isolating these two arduinos is that one of the arduinos is “floating” on the HV circuit and is using an ADC to read high voltages on the high voltage circuit cannot be grounded with our low voltage circuit with the other arduino on it.

I have it set up so that the arduino on the low voltage circuit plugs into the “in” side of the isolator, and it provides isolated 5v to the arduino on the high voltage circuit as it should.

This is the product I bought:

For isolation this board has I2C isolator ISO151 and for power isolation it has R1SE.

Attaching the sch for you ref as well.
ISO_sch.pdf (31.7 KB)

Thank you for the reply,

I know what chipsets the board has, but I am wondering why it is not permitting bidirectional communication. The ISO1541 is a bidirectional isolator, but I can only communicate one way.


I will recommend checking with TI tech support. I never used this part in such environment as yours.