A memory controller comprising: a delay circuit, configured to use a first delay value and a second delay value to respectively delay a sampling clock signal to generate a first and a second delayed sampling clock signal; a sampling circuit, configured to use a first edge of the first delayed sampling clock signal to sample a data signal to generate a first sampling value, and configured to use a second edge of the second delayed sampling clock signal to sample the data signal to generate a second sampling value; and a calibrating circuit, configured to generate a sampling delay value according to the first delay value based on the first sampling value and the second sampling value. The delay circuit uses the sampling delay value to generate an adjusted sampling clock signal and the sampling circuit sample the data signal by the adjusted sampling clock signal.