In short, I am in the process of connecting the AD5933 Eval Board "EVAL-AD5933EBZ" to the Microchip AVR-IoT WG Development Board. I am not having very much success in communicating with the impedance measuring device. I can successfully communicate with the eval board using the AD5933 Software Evaluation and Arduino Mega 1280 development boards.
After digging a little deeper into the issue I noticed the ATMEGA4808 on the Microchip AVR-IoT WG Development Board seems to be pulling both the I2C SCL and SDA lines low. I am assuming this is when the I2C block is being enabled. In the scope image below there's a 1/2us glitch before the SDA line is pulled low.
Has anyone come across such an issue before?
** EDIT **
After further investigation, it seems the TWI flush function is causing this.
Writing a '1' to this bit generates a strobe for one clock cycle disabling and then enabling the master.
TWI0.MCTRLB |= TWI_FLUSH_bm;
I need to test with everything connected again to see my communication issues have been fixed.