Need for clock on XIN for I2C to work for CY22150, CY22801, CY22393, CY22394 and CY22395

Question: Can the I2C (serial) interface on the CY22150, CY22801, CY22393, CY22394 or CY22395 be used if the XIN (XTALIN) reference clock is stopped?

 

Answer:
 After power on, the XIN (XTALIN) input must toggle a minimum of 4 times in order to enable the I2C interface.  Afterwards, I2C requires only the I2C clock (SCLK) for operation, and it does not matter if the XIN (XTALIN) input is toggling or not.