This checkbox enables tracing of the external I2C bus drivers. When enabled, any external changes that occure on the I2C bus are logged to the trace buffer. External changes are imposed by external devices and occure when the external device updates its I/O lines NOT when the EEPROM simulator polls the I/O lines. The trace has a time stamp (clock cycle count) which can be used to tie the EEPROM simulation to the CPU cycle of the controlling processor.