how to connect more than 2 chips over I2C ?

I have custom board with 4 chips, communicating over I2C. The problem is that I cannot have 4 chips talking to each other.

I can only communicate between 2 chips. As soon as I enable I2C on third chips the communication stops.

One is setup as master transmit the rest as slave receive. My guess maybe it is something do to with CLK line as soon as the 3rd or 4th is enabled.

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Guru

The Slave drives the transaction and pacing.

Make sure that the pins are Open Collector/Drain.

Make sure the Slaves are NOT responding to the same addresses.

Perhaps use serial output to understand the behaviour/interactions of the slaves.

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ST Employee

Hello @MNapi ,

You may connect an Oscilloscope to see the SDA and SCL behavior.

Foued

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