In an integrated circuit device that outputs data values during respective transmit intervals defined by transitions of a transmit clock, the phase of the transmit clock is shifted by half a transmit interval to enable a timing calibration operation. Thereafter, a sequence of data values is transmitted to another integrated circuit device in response to the phase-shifted transmit clock and a samples of the sequence of data values are received from the other integrated circuit device. The received samples are compared with the sequence of data values to determine a phase update value, including comparing at least one received sample with two adjacent data values within the sequence of data values, and the phase of the transmit clock is incrementally advanced or retarded according to the phase update value.