I2C - communication mulfunctioning on Stellaris EK-TM4C129E Launchpad in Energia - TivaC/CC3XXX Posted October 20, 2017 Hello it looks like I bumped into an issue which might be of interest, and needs to be investigated. I have a string of I2C devices running on i2C Bus on Arduino Mega (MCP4531 potti, LM-75 Temp sensor, 2x PCF 8575 I/Expanders). All running smooth. The next step I had to exchange the Mega with Tiva Stellaris Launchpad (EK-TM4C129E ), which I did, I havent changed anything on the setup besides the Mega2560 with Launchpad. While running the i2C scanner I saw, full Bus of devives. Furthermore I changed the i2C modules (0,1,2 with setModule()) nothing changed, same issue persists. Pull-ups varied from 1KOhm - 9Kohm, still same issue. Anyone experienced something like that before?