I have a LPC11E14 using it over I2C as a slave.
Now when the micro controller is not powered, I can see a leakage current on the I2C pins PDIO0_4/SCL and PDIO_5/SDA into the controller. This leakage current is influencing our I2C host and lowers the I2C voltage level so much that other devices on the bus are influenced.
This effect starts at ~40°C and gets worse at >+60°C.
As soon the controller is powered the bus works fine.
have ever had a similar effect ?