ESP32 Forum

I want to connect 4 ADCs (ADS1015/1115) to an ESP32-S3 for a total of 16 inputs.

The data sheet for the ADCs suggest up to 4 can be connected on I2C line by addressing them appropriately.

But I've noticed that the ESP32-S3 can support 2 I2C controllers/ports.

If I want to sample these ADCs as fast as possible, would it be advantageous to split them up and put 2 ADS on each port?

Thanks.

It might when using 100kHz I2C. At 400kHz the potential gains would be diminishing though. If you schedule the I2C transactions right that is.

IIRC, for every sample we need
1+9+9+9+9+1 = 38 I2C clocks (one 16-bit register write) to select the channel and start the conversion, plus 1+9+9+1+9+9+9+1 = 48 clocks (one 16-bit register read) to read the result. That's 86 I2C clocks total per sample, 860us @ 100kHz. Incidentally, this is the same amount of (bus) time it takes to run 4 ADCs @ 400kHz.
The a/d conversion takes about 1160us @ 860 SPS, so at 400kHz the I2C is not the limiting factor.