Tool/software:
Hi Team,
I have a question about TCAL6416RTWR expander.
We would like to use two these ICs in one system, each one with a different I2C address (set by the ADDR pin). The VCCI will be powered from 3.3V and VCCP from 1.8V. In one expander the ADDR will be tight to GND and in the other directly to VCCP (as recommended in the DS). SDA, SCK and RESETs will be pulled up to VCCI. The I2C bus will be also shared with an EEPROM powered from 3.3V. The intended power sequence is as follows: we turn on 3.3V, read EEPROM and then we turn on 1.8V.
The question is how would the expanders behave in the case when there is VCCI supply and VCCP supply is not turned on yet – i.e. with two expanders having ADDR pin low (or in fact one of them having the ADDR input floating). Is there a risk of the I2C bus getting stuck by the expanders, for instance if we accidentally try to communicate with them before turning on of VCCP or during the reading of the EEPROM (with VCCP turned off)? Are there any other issues we should take into account in this use case?
Best regards,
Bartosz
