I have an implementation of the I2C peripheral that is working on the F28075 in both digital loopback mode and standard mode (communicating to a slave device). The same code was ported over to the LAUNCHXL-280025C. I was successfully able to use digital loopback mode on the F280025C and see that the received data matched the transmitted data. When I turn off digital loopback mode and attempt to perform an I2C write I see both the SCL and SDA lines pulled low and remain low until the board is reprogrammed.
I confirmed that I have proper control of the correct pins by using them as standard GPIO and driving a square wave on both pins. Any suggestions on why digital loopback mode works, but communicating through the hardware does not? From my understanding, if digital loopback mode works then the only things left in the chain are the output pins, output pads, and the trace to the GPIO pin. Any suggestions on what to try next?
