P82B96: Use as GPIO Extender

Hi Clemens, thanks for the quick response.

My intention is to have microcontrollers at the master and slave sides operating as I2C, then under certain conditions the I2C lines will switch to GPIO functionality with the slave side controlling the state of the lines. The microcontroller GPIOs will be configured to operate in open drain mode in all situations.

Hi Matt,

The VIT thresholds are consistent across the VCC range of the device. 

P82B96 is an open-drain I2C buffer. Following these VIT thresholds, the buffer will either release HIGH, or drive strong LOW. 

Is there any point where the MCU would toggle LOW while the target pushes HIGH? What I am asking is if there is any instance in time where the MCU and the target communicate at the same time? 

Regards,

Tyler

Hi Tyler, 

Not on the same line. In the case of switching from I2C mode to GPIO mode, the master will send a specific code the the slave. At this point the slave will control the state of one of the I2C lines as a GPIO in order to signal an event to the master side. When the master side needs to signal the slave to re-enter I2C mode it can pulse the other I2C line, so there will never be any time that one line could be driven from both sides at the same time.

Hi Tyler, 

Thanks very much for your help!

Hi Matt,

Thank you for posting your question. If you have any additional questions, feel free to submit another e2e question. 

Regards,

Tyler