Some customers noticed that Tracii 400 board is unable to pull the SDA and SCL lines low enough for communication. This happened only when using small external termination resistors (about 1k Ohm). This problem is caused by two serial resistors (R5/R6) which are used to protect the SDA and SCL line of Tracii 400. If you experience the same problem, these resistors which have a value of 220 Ohm must be replaced by some lower values (we recommend 22 Ohm).
You can find the resistors R5 and R6 close to the I²C-bus connector. R5 protects SCL and R6 is used for the SDA line.
