The Freedom-K64F is an ultra-low-cost development platform for Kinetis K64, K63, and K24 MCUs.

K64F I2C slave device clock stretching and I2C hanging/freezing

20 Nov 2017


I have a BNO055 chip I am trying to use with a FRDM-K64F, however to not much success, it will work for perhaps 3 or 4 I2C messages then both SDA and SCL are held low and do not recover.

I believe this is from the slave clock stretching, is there a bug fix for the K64F I2C library, is this a known issue? How would I go about fixing this?

pull ups for the I2C lines are both 4.9K



21 Nov 2017

I am using a K64F with a TI BQ34Z100. The BQ is an awful SCL stretcher. I haven't had problems with I2C communication.

Have you tried running I2C at 100KHz? Also, 4.7k is a little weak - but should be ok. I recommend 2.2k- 3.9k