title: I2C slave - clock stretching
body: <p>Do you guys know how to enable the clock stretching for I2C slave?</p>
  
  <p>Is it enough to just put this function <code>I2C_StretchClockCmd(I2C2, ENABLE)</code> in the initialization of I2C?</p>
  
  <p>How does clock stretching work exactly?</p>