TCA9803: B-side for master and A-side for slave could be OK?

Kazuhiko Hirano

Part Number: TCA9803

Hello,

My customer would like to connect SDAB/SCLB/EN to an I2C master device and connect SDAA/SCLA to an I2C slave device. Is this OK or any problems could occur?

Best regards,

K.Hirano

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 317350 points

This is OK. I²C is bidirectional; on the electrical level, master and slave devices behave the same.

0 Tyler Townsend over 2 years ago

TI__Mastermind 48248 points

Hi Kazuhiko,

I agree with Clemens. I2C is a bidirectional communication protocol, able to transmit and receive in both directions. It does not matter which side the controller (master) and target (slave) device is connected to.

Only recommendation when using TCA9803 is not to connect two or more B-sides together, otherwise oscillations could occur.

Regards,

Tyler

0 Kazuhiko Hirano over 2 years ago in reply to Tyler Townsend

TI__Genius 15118 points

Clemens, Tyler,

Thank for you guy's responses.
I have one more question.
What if a master device I2C pins are open drain?
Pull up resisters on B-side could be OK?

Best regards,

K.Hirano

0 Clemens Ladisch over 2 years ago in reply to Kazuhiko Hirano

Guru 317350 points

All I²C pins are open drain.

But the TCA980x has an integrated current sources; you must not add pull-up resistors on the B side.

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TCA9803: B-side for master and A-side for slave could be OK?