This anomaly applies to Revision 1, build codes QKAA-D00.
Application, Network
The low period of the SCL clock is too short to meet the I2C specification at 400 kHz. The actual low period of the SCL clock is 1.25 µs while the I2C specification requires the SCL clock to have a minimum low period of 1.3 µs.
Using TWIM at 400 kHz.
TWI communication might not work at 400 kHz with I2C compatible devices.
If communication does not work at 400 kHz with an I2C compatible device that requires the SCL clock to have a minimum low period of 1.3 µs, use 390 kHz instead of 400 kHz by writing 0x06200000 to the FREQUENCY register. With this setting, the SCL low period is greater than 1.3 µs.