When I use a IO I2C timing to drive MFRC630, I found it always failed, the timing is very strict with delay time between two bytes or between two data sequence.
Please check the section on the datasheet section 12.1 Timing characteristics there is a table explaining the timings for the I2C bus also in the and in the 7.4.4 I2C-bus interface there is the explanation of all the bus, if this not help please send me more information about what command are you sending also if you have images of the I2C bus on your oscilloscope or something like that, can help !
